Carcinization in the Anomura - fact or fiction? I. Evidence from adult morphology

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1 Contribtions to Zoology, 67 () 79- (997) SPB Academic Pblishing bv, The Hage Carcinization in the Anomra - fact or fiction? I. Evidence from adlt morphology Patsy A. McLaghlin & Rafael Lemaitre Shannon Point Marine Center, Western Washington University, Anacortes, Washington, U.S.A.; Department of Invertebrate Zoology, National Msem of Natral History, Smithsonian Instittion, Washington, D.C., U.S.A. Keywords: Carcinization, Anomra, Pagroidea, Galatheoidea, Hippoidea, Lomoidea, Pagridae, Lithodidae, adlt morphology, phylogeny Abstract Carcinization, or the process of becoming a crab, has been, and contines to be, a focal point of anomran evoltionary hypotheses. Traditional examples of carcinization in the Anomra are most celebrated among hermit crabs bt certainly are not limited to this grop. Carcinization, if it has occrred, has done so independently in all major anomran taxa. In this critiqe, the traditional examples of carcinization in the Anomra are reviewed and more modem variations on the theme assessed. Potential pathways of carcinization are examined from perspectives of adlt morphology in the Pagroidea, Galatheoidea, Hippoidea and Lomoidea, with emphasis on the Pagroidea. Specific attention is given to the theoretical transformation of a hermit crab-like body form into a "king crab"- like Iithodid crab. Reslting coercive evidence indicates: () that while the evoltion of a crab-like body form certainly occrs, the traditional applications, based on inadeqate and often inaccrate data, are flawed; and () that Iithodid crabs did not arise from a hermit crab predecessor throgh the process of carcinization. Resme La carcinisation (processs par leqel on devient n crabe) a ete, et contine d'etre, n point focal des hypotheses sr revoltion des Anomres. Les exemples les pls conns de carcinisation chez les Anomres sont fornis par les Pagres, mais le phenomene n'est certainement pas limite a ce grope. S'il y a e carcinisation, celle-ci s'est independamment prodce dans tos les grands gropes d'anomres. Dans le present aperc critiqe on passe en reve les exemples traditionnels de carcinisation dans ce grope et on evale les variations pls recentes sr ce theme. Dans la perspective de la morphologie des adltes on examine les voies potentielles de la carcinisation chez les Pagroidea, Galatheoidea, Hippoidea et Lomoidea, en insistant sr les Pagroidea. Une attention speciale est accordee a la transformation - en theorie - d'n habits d type Pagre dans celi d'n crabe lithodide. L'&vidence qi s'impose indiqe: () q'ne evoltion vers n habits de crabe existe certainement, mais qe les interpretations traditionnelles de ce phenomene, basees sr des donnees inadeqates et sovent deporves de precision, sont erronees; () qe les crabes lithodides n'ont pas evole par carcinisation a partir d'n ancetre Pagre. Introdction A nmber of decapods look like crabs, bt do not qalify as "tre" crabs (Brachyra) becase of adlt morphological inconsistencies or larval characteristics. Presmably, to become a "tre crab" reqires that a reptant decapod ndergo carcinization (Borradaile, 96) or brachyrization (StevCi, 97). Althogh the two terms appear here to be synonymos, we believe that not all athors who have employed "carcinization" or "brachyrization" have had qite the same phenomenon in mind. For example, Martin & Abele (986) defined carcinization as the redction and folding of the abdomen beneath the thorax, whereas Slys (99) sed carcinization to mean the evoltion of a crab-like appearance as in lithodids. To Blackstone (989) hermit crabs became carcinized throgh broadening of the carapace and redcing the habitation of shells. In this first article, we address anomran carcinization only from the perspective of adlt morphology. We accept that the Anomra, as defined by McLaghlin (98b) and McLaghlin & Holthis (985), inclde for major taxa: Galatheoidea, Hippoidea, Lomoidea, and Pagroidea. We recognize Forest's (987) elevation of the Pagroi-

2 8 PA. McLaghlin & R. Lemaitre - Carcinization in the Anomra dea to Section Pagridea with sperfamilies Pagroidea and Coenobitoidea; however, hierarchical ranking has no bearing pon or discssion. We are aware of the propositions made recently by Williamson (99) and by Spears et al. (99), bt dispted by Scholtz & Richter (995), that the Dromioidea are actally anomrans. Similarly, we note, bt do not concr with, the reintrodction of "Anomala" by the latter athors. Borradaile (96), who first proposed the term carcinization, implied a qite specific meaning, i.e., "... one of the many attempts of Natre to evolve a crab", and sed for his example of carcinization the hermit crab Porcellanopagrs sp.; StevCi (97), on the other hand, proposed the term brachyrization as a "more general term relevant to all crabs as a whole, withot regard to shape and organizational level". Wolff (96b), Ginot (979), and Trkay (986) appear to have sed carcinization, as Williamson (99) and Martin & Abele (988) have sed brachyrization, in the sense of independent, convergent, evoltionary phenomena leading to a crab-like body form. In this review we se carcinization in the sense of Wolff (96b), Ginot (979), and Trkay (986). The only decapods that have demonstrated these apparently evoltionary tendencies of carcinization are members of the Anomra and Brachyra. Presmably, in the Pagroidea carcinization wold ltimately lead to the evoltion of the lithodid body form, and in the Galatheoidea, to the evoltion of the porcellanid body form. The Hippoidea and Lomoidea wold appear to have already reached a certain level of carcinization bt with no distinct pathways evident. Or intent here is not to discss anomran Dhylogenetic relationships in great depth, bt rather to investigate the evoltionary pathways ;hat spposedly have given rise to the crab-like ody forms of anomran taxa, with particlar emphasis on the Pagroidea. As previosly indicated, the term carcinization vas introdced by Borradaile (96) to describe he phenomenon he perceived to be the transfornation of a typical shell-dwelling hermit crab nto a crab-like animal no longer dependent pon i spiraled gastropod shell for protection of its nembranos abdomen. However, the phylogeny of the crab-like lithodids had been explored in detail earlier both by Boas (88a, b) and Bovier (89a-c; 895a, b; 897). Additional examples of presmed pagroid carcinization were reported by Bovier (896) and Borradaile (96) in Ostraconots A. Milne Edwards, 88, and Tylaspis Henderson, 885; in Probeebei Boone, 96b and Labidochirs Benedict, 89 by Wolff (96b) and Blackstone (989); in Solitariopagrs Trkay, 986, by Trkay (986); and in Pagrs hirstiscls (Dana, 85) by Blackstone (989). As envisioned by most carcinologists, the evoltionary processes involved the modification of an anomran having an inflated, elongate cephalothorax into one that was broadened and somewhat flattened. Similarly, the long, freqently articlated, and relatively weakly calcified abdomen was converted into one that was not only redced, bt also bent nder the thorax and ltimately pressed closely against the sternm. Sch transformations reqired modifications not only to the thorax and abdomen themselves, bt also to the entire animal. Morphological diversity within the major anomran taxa precldes any sweeping generalizations. Among these taxa, carcinization wold appear to have been an independent phenomenon that proceeded at varying rates. Historical review of reported instances of carcinization Pagroidea The most well-known of these theories are those of Boas (88a, b, 9), Bovier (89a, c, 895b, 897), Cnningham et al. (99), and Richter & Scholtz (99) who perceived evoltion of Lithodes Latreille, 86 (inclding Paralithodes Brandt, 88) from a species of Pagrs Fabricis, 775 (Fig. ), or another related gens. Althogh earlier athors (e.g., H. Milne Edwards, 87; H. Milne Edwards & Lcas, 8; Brandt, 88, 85, 85) had proposed a relationship between Lithodes and Pagrs, Boas (88a, b) was the first one who attempted to provide morphological data to sbstantiate sch a relationship. These inclded similarities in the strctre

3 Contribtions to Zoology, 67 () Fig.. Hypothetical transformation of Pagrs Fabricis, 775 to Lithodes Latreille, 86. To explain the asymmetry of hermit crabs, Perez (9) sed a fictitios example of a person holding a package while descending on a dextrally coiled stairwell similar to a snail shell (left). The person wold find it more comfortable to carry the package on the left hand becase there is more space on that side. The implication is that se of dextral shells by hermit crabs led to an abdominal asymmetry favoring the left side. Typical shelldwelling hermit crabs sch as Pagrs aletics (Benedict, 89) (bottom, after Benedict, 9), presmably nderwent transformation to crab-like animals no longer dependent on gastropod shells sch as Lithodes mrrayi Henderson, 888 (top, after Henderson, 888). Not to scale.

4 8 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra of the mothparts and gills; fsion of the sternite of the first abdominal somite with the last thoracic somite; and redction in abdominal tergites. Bovier (89c) similarly derived the lithodids from the pagrids, and sbseqently (Bovier, 895b, 897) from an ancestor specifically in which females were provided with a pair of gonopods on the first abdominal somite, sch as seen in Pylopagrs A. Milne Edwards & Bovier, 89. He concrred with Boas (88a, b) on the strctral similarities between pagrids and lithodids, bt went a step frther to propose a series of gradal and progressive stages in transforming the pagrid abdomen into that of a typical lithodid. These changes called for the complete loss of abdominal tergites throgh 5 in the pagrid precrsor (Fig. a), and the secondary origin of lithodid tergal plates throgh the development and fsion of calcareos nodles formed within the initially membranos integment. As may be seen in Figs. b-j, commencing with Hapalogaster Brandt, 85 (Fig. b), a seqence was envisaged where, in varios genera, the tergites of the second somite were replaced by calcified nodles that became fsed in sch a manner as to create paired marginal (m) and lateral plates (). The tergites of somites -5 were markedly redced, leaving an almost totally membranos area. This redction was followed with a more clearly marked delineation of an npaired median plate (M); the entire dorsal srfaces of somites -5 became covered with calcareos nodles. In Paralithodes for example (Fig. e), fsion of the nodles on the dorsal srfaces of somites -5 began to occr laterally to form a series of contigos plates, and externally a series of small marginal pieces began to develop; nodles in the median areas were arranged into transverse sets. Sbseqently, the median nodles of somites -5 fsed to form plates corresponding to, bt separated from, the lateral plates by a free, or partially fsed, nodlar strip. Finally, fsion of all marginal pieces to their respective lateral plates began, along with the formation of intercalary rods (i) between the lateral and median plates by the fsion of the free and partially free nodles. Complete plate fsion, sch as seen in Cryptolithodes Brandt, 88 (Fig. j) reslted in somites -5 being represented by sets of solid, contigos plates, the tergites of somite 6 and the telson remaining as distinct plates. Boas (9) reviewed not only mothparts and gill strctre of Lithodes, bt thoracic appendages as well, and conclded that "Lithodes [inclding Paralithodes] was evolved from a hermit crab, which was probably very closely related to the contemporary genera Nematopagrs A. Milne Edwards & Bovier, 89 and Pylopagrs..." He disconted Bovier's (89c," 895b, 897) hypothesis that Hapalogaster might be intermediate in the transformation of the pagrid abdomen to the typical lithodid abdomen. Boas (9) pointed to sch similarities in Pagrs (as Epagrs Brandt, 85), Nematopagrs and Lithodes as the strctre and msclatre of the right chelipedes, the presence in all three of an accessory tooth on the crista dentata of the third maxillipede, the distance between the endopod and the endites of the first maxillipede, and other aspects of the mothparts. Most noteworthy was Boas' derivation of the abdomen of Lithodes from Nematopagrs (Fig. a, b). In Nematopagrs he fond the sternite (s) of the first abdominal somite compact, ndivided and partially fsed to the last thoracic somite. A similar condition occrred in Paralithodes (as Lithodes), with a pair of pleopods emerging from the sternm of the female in both species. The sternites of somites - 5 were markedly redced in Nematopagrs, being represented laterally by the acetabla (a) of the pleopods. On the second somite these sternal plates were present on both sides of the abdomen, separated by a broad membranos area; on somites -5 they were present on the left side only. Remnants of the tergites (d) of the abdominal somites were connected to the sternal plates either directly by a setose edge (h) or by a membranos space; the tergal plates themselves were also divided into two parts, of which only those of the first and second somites adhered closely. The tergal plates on the third to fifth somites were separated by membranos areas. Boas fond that the second somite in Paralithodes differed in having a large transverse plate composed of five pieces. He interpreted the central portion of this plate as the median membranos part of the Nematopagrs second somite; the adjacent

5 Contribtions to Zoology, 67 () ^e -A;K/ Fig.. Stages in the transformation of the abdomen from a pagrid to a lithodid as proposed by Bovier (895b, 897): a, pagrid precrsor; b, Hapalogaster Brandt, 85, dorsal (top) and ventral (bottom) views; c, Dermatrs Brandt, 85, posterior (top) and dorsal (bottom) views; d, Neolithodes A. Milne Edwards & Bovier, 89b, posterior (top) and dorsal (bottom) views; e, Paralithodes Brandt, 88; f, Lithodes Latreille, 86, posterior (top) and dorsal (bottom) views; g, Lopholithodes Brandt, 88, posterior (top) and dorsal (bottom) views; h, Paralomis White, 856; i, Rhinolitodes Brandt, 88; j, Cryptolithodes Brandt, 88. Abbreviations: i, intercalary rods;, lateral plates; m, paired marginal plates; M, npaired median plates. Nmbers indicate abdominal somites (-6) and telson (7). (Modified from Bovier, 897.) plates were homologos with the tergal plates of the pagrid. In Nematopagrs, and Pagrs, the tergal plates are joined to the sternal plates of the somites by membranos strips, and Boas conclded that it was from these that the small marginal plates seen in Paralithodes had developed. Boas reasoned that the loss of ropods in lithodids was a direct reslt of loss of fnction; and that elongation of the forth pereiopods reflected a retrn to typical decapod strctre. Before conclding his stdy, Boas had the opportnity to examine specimens of Pylopagrs, a gens with gonopod bearing females, bt one in which the males, like male lithodids, were not eqipped with sexal tbes. His conclsion therefore became one in which he evolved Lithodes from an ancestor

6 8 P.A. McLaghlin & R, Lemaitre - Carcinization in the Anomra ^\ Fig.. Transformation of the pagrid abdomen to the lithodid as hypothesized by Boas (9): a, dissected abdomen of Nematopagrs A. Milne Edwards & Bovier, 89, showing different parts; b, abdomen of Paralithodes Brandt, 88. Abbreviations: a, acetabla; d, tergite; f, first pleopod; h, setose edge ("Haargebrame"); s, sternite. Nmbers denote abdominal somites and telson (modified from Boas, 9). closely related to Nematopagrs and Pylopagrs. More recently, Paralithodes was not only derived from Pagrs (Fig. ) bt the proposition was made by Cnningham et al. (99) that P. camtschatica (Tilesis, 85) and Lithodes aeqispina Benedict, 895 were more closely related to Pagrs bernhards (Linnaes, 758) and Pagrs acadians (Benedict, 9) than were the latter two species to Pagrs pollicaris Say, 87 and P. longicarps Say, 87. These athors went so far as to propose that the reslts from their ribosomal RNA stdies jstified the inclsion of these two lithodid species in the gens Pagrs. There is no dobt that a genetic relationship exists between pagrids and lithodids. However, the stdy by Cnningham et al. (99) was based on data derived from only eight species from a gene pool in excess of 9 species. In view of the nmber of morphologically, and seemingly phylogenetically, more closely related intermediate taxa within the Pagroidea, the approach of Cnningham et al. is in need of an expanded data base. The latest proposal for derivation of the Lithodidae from the Pagridae is that of Richter & Scholtz (99). While not sggesting any direct line(s) of descent, these athors similarly con-

7 Contribtions to Zoology, 67 () \ \ 97 C Pagrs polllcarls (New England) Pagrs polllcarls (Gtf of Mexico) Pagrs long Icar ps We* England) Pagrs longlcarps IUU (Dif of nenco) Pagrs berntiards (Erope) Pagrs acad I ans (New inr<a England) LP'^iQy 96 I Ellasochlrs tenlmans [sic] (Bering Seal Labldochlrs splendescens (Bering Sea) LithoGes aeqlsplna (Bering Sea) ParglHhodes camtschallca (Bering Sea) 88 Cllbanarls vlitats (Gll or Mexico) Coenoblta (sp) (Glf or Menco) Artemla sallna. nits fig.. Evoltion of pagrid to lithodid (or "Hermit to King") based on DNA evidence. Letters A-C refer to modes estimating dates of geological divergence. Crabs shown illstrate presmed stages of carcinization: top, Pagrs bernhards (Linnaes, 758), a typical gastropod shell-living hermit crab; middle, Labidochims splendescens (Owen, 89), a partially carcinized hermit crab displaying redced dependence on gastropod shells with only its abdomen protected by the shell; bottom, Paralithodes camtschatica (Tilesis, 85), a flly carcinized King Crab that never occpies a shell. (After Cnningham et al., 99.) elded that the Lithodidae represent a grop of secondarily free living "asymmetrical" hermit crabs. In their stdy, they presented a series of eight characters that separated their "probably" paraphyletic "symmetrical" Pylochelidae from the monophyletic "asymmetrical" hermit crabs, which inclded Diogenidae + Coenobitidae, Parapagridae, and Pagridae-Lithodidae. Their stdy addressed the isse of carcinization only in their conclsion that the lithodid characters they considered reflected a change toward a free living habit. Within the Pagridae, several other instances of carcinization have been reported. Whereas Bovier (89c, 895b, 897) and Boas (88a, b, 9) placed primary emphasis on changes in the abdomen and pleopods, Borradaile (96) emphasized changes in the cephalothorax. He described carcinization in a species of Porcellanopagrs Filhol, 885 (Fig. 5) as a phenomenon "qite independent" of carcinization in other anomrans. Borradaile interpreted the widening of the sternite of the third maxillipedes seen in the Pagridae and Parapagridae as the first step in the carcinization process. Frther advances inclded broadening of the cephalothorax and accompanying calcification, as depicted by Labidochims splendescens (Owen, 89) (Fig. 6a, b), Ostraconots (Fig. 6c), Tylaspis (Fig. 6d), Porcellanopagrs (Fig. 6e), and the semi-terrestrial cocont crab, Birgs latro (Linnaes, 767) (Fig. 6f). To emphasize his argment for independent pathways of carcinization in these taxa, Borradaile (96) noted a nmber of dissimilarities among them, e.g., male gonopod development, chelipede and pereiopod strctre, development of a rostrm, etc.; he gave only passing attention to the differences in redction and/or calcification of

8 6 P.A. McLaghlin & R. Lemaitre ~ Carcinization in the Anomra ig. 5. Porcellanopagrs Filhol, 885, "probably"/', edward- Filhol, 885, as viewed by Borradaile (96): a, ovigeros male, dorsal view; b, same after removal of most eggs (end of fth leg shown enlarged). Abbreviations: c, cervical groove; r, strm. Nmbers are "sidelobes" of cephalothorax. (After srradaile, 96.) e abdomens. He set Porcellanopagrs apart by hat he perceived to be the niqe dorsal posi- )n of the female pleopods, and began his dismrse with a detailed description of a female tribted "probably" to Porcellanopagrs ed- xrdsi Filhol, 885. Forest (95a, b) redescribed edwardsi and discssed its systematic position ithin the Pagridae, bt did not address any pects of carcinization. For the prpose of the crrent discssion, we esent a brief morphological overview of Porllanopagrs, based on or own examination of edwardsi. The cephalothorax (Fig. 7a, c) is Dadened, flattened and drawn ot into a series lobes, the centermost being the prominent rosim (r). Borradaile (96) and Forest (95a) jntified the remaining lobes only by nmber; wever, we believe that the anterolateral lobes >resent extraordinarily well-developed lateral projections (lp) of the typical pagrid shield (Fig. 7b). The first two of the three lateral wing-like expansions appear to be expansions of the lateral margin of the shield itself. The third, and most posterior lobe, which is clearly delineated from the other two by the cervical groove (eg), is probably a calcified and expanded portion of the posterior carapace. The hard strip of cticle present directly behind the midpoint of the posterior margin of the carapace was considered by Borradaile (96:, fig. a) to be a portion of the last thoracic somite. Forest (95a) reported that the last thoracic tergite was represented by a narrow chitinos band, and we concr. As may be seen in Fig. 7d, a transverse calcified band is also apparent behind the posterior carapace margin. In or specimens there is a clear demarcation between the chitinos last thoracic segment (as determined by the positions of the acetabla of the fifth pereiopods) and the tergite containing the calcified strip, which we interpret to be a calcified portion of the tergite of the first abdominal somite. Borradaile (96) reported two tergal sclerites present on the second abdominal somite and single plates on the left third and forth somites, with only faint thickenings on the right. However, both Forest (95a) and we were able to distingish well-formed, entire (albeit not calcified), tergal plates on somites -5 (Fig. 7d) in both males and females. A more significant point is the strctre and placement of the female npaired pleopods. Borradaile (96) and Forest (95a) both stated that the female pleopodal endopods are well developed and the exopods redced. Borradaile (96) also considered the pleopods to be dorsal in position, with pi almost median and the other two positioned sccessively more to the left, indicating a position analogos to that of a spirally twisted abdomen. One might well be drawn to this conclsion if the abdomen were partially contracted, as in many preserved specimens. However, when the abdomen is preserved in a relatively relaxed state, it is clear that the pleopods (pl-pl) as well as the ropods sit in a straight line on a symmetrical, albeit greatly swollen abdomen (Figs. 6e, 7d). In a small female specimen with the pleopods aligned in the normal

9 Contribtions to Zoology, 67 () Fig. 6. Examples of advanced cases of carcinization in hermit crabs according to Borradaile (96). Labidochirs splendescens (Owen, 89): a, whole animal; b, cephalothorax and cephalic appendages (after McLaghlin, 97); c, Ostraconots spatlipes A. Milne Edwards, 88 (after A. Milne Edwards & Bovier, 89); d, Tylaspis anomala Henderson, 888 (after Lemaitre, in press); e, Porcellanopagrs edwardsi Filhol, 885 (after Forest, 95a); f, Birgs latro (Linnaes, 758) (after Alcock, 95). Not to scale.

10 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra optp 7. Morphology of' Porcellanopagrs-edwardsi Filhol, 885, (a, c, d); b: Pagrs Fabricis, 775: a, dorsal view (pereiopods -5 hown); b, left side of'typical pagrid shield, branchiostegite and left half of cephalothorax as seen in Pagrs (after Pilgrim, I; c, right side of cephalothorax, lateral view; d, abdomen, dorsal view. Abbreviations: eg, cervical groove; lp, lateral projection; ea transversalis; optp, oter pterygostomial plate; r, rostrm. Nmbers indicate lateral lobes of carapace (a, c) or abdominal es (d); arrow points to calcified rod of abdominal somite. Not to scale. al position, it is the endopod that is redced. n the pleopods have eggs attached, the pleoare twisted to allow the eggs to be carried illy; therefore the impression is given that it is the exopod that has ndergone redction. Boone (96a, b) described what she believed to be a new and primitive macrran representing a new family of decapods. In his redescription of

11 Contribtions to Zoology, 67 () Alainopagrs Alainopagroides Fig. 8. Classical examples and recently described candidates of carcinized hermit crabs: a, b, Probeebei mirabilis Boone, 96b (after Wolff, 96b); c, Solitariopagrs profnds Trkay, 986 (after Trkay, 986); d, Alainopagrs crosnieri Lemaitre & McLaghlin, 995 (modified from Lemaitre & McLaghlin, 995); e, Alainopagroides lemaitrei McLaghlin, 997 (after McLaghlin, 997). Not to scale. Probeebei mirabilis Boone, 96b, Wolff (96a, b) correctly recognized this nsal, deep-water species as a pagroid (Fig. 8a, b), and he interpreted it as another example of carcinizatton within the grop. Althogh he relied heavily on Borradaile's (96) carcinization hypothesis, Wolff (96b) did address abdominal changes in considerable detail He noted that Labidochirs

12 ? P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra iplendescens (as Pagrs) and Probeebei mirabilis shared the same carapace grooves and general calcification of the cephalothorax. However, :he abdomen of L. splendescens, albeit redced, was membranos. The abdomen of P. mirabilis was more calcified than in any other pagroid; :he development of the second abdominal tergite was seen as more parallel to Lithodes. The recently described genera, Solitariopa- %rs (Fig. 8c), Alainopagrs (Lemaitre & McLaghlin, 995) (Fig. 8d), and Alainopagroides McLaghlin (997) (Fig. 8e) all bear certain marked resemblances to Ostraconots and Porcellanopagrs, and similarly might be considered candidates for the traditional carcinization hypothesis. In fact, Solitariopagrs was considered intermediate between the latter two genera by its athor (Tiirkay, 986), who regarded it as an another example of a hermit crab that had abandoned its gastropod shell and had besome at least partially carcinized. Only in Solitariopagrs and Porcellanopagrs is the very well-calcified shield flattened and drawn ot laterally into three broad projections; however, in all five genera the sternites of the second and third thoracic segments are broadened. While nearly complete calcification of the posterior carapace occrs in the monotypic Ostraconots, only varying degrees of weak calcification are seen in the other for genera. Species of all five genera have redced abdomens; males all lack pleopods and females have pleopods on only somites two throgh for. The abdomens of Porcellanopagrs, Ostraconots, and Alainopagroides are membranos and the second throgh fifth tergites are only faintly indicated. However, in Solitariooagrs and the monotypic Alainopagrs these tergites are chitinized or calcified to some extent. The similarly monotypic Alainopagroides appears to be the only one to inhabit a gastropod shell. An interesting hypothesis of carcinization involving Pagrs was proposed by Blackstone (989). In what he reported to be sothern and northern poplations of the common, eastern Pacific, intertidal hermit crab, Pagrs hirstiscls (Dana, 85) (Fig. 9a, b), Blackstone docmented the progressive broadening of the anterior calcified carapace (shield), and the se of gastropod shells of sccessively smaller size in poplations from soth to north. His findings led him to sggest that: () some hermit crabs possess intrinsic characters that can lead to carcinization; () ecological conditions favoring carcinization may exist at polar, or at least northern, latitdes [northern poplations have broader, often more exposed carapaces]; and () size increase [as seen in the more northern poplations] may be associated with redced shell-living and carcinization. Provocative as his hypothesis is, the fact that his sothern and northern poplations actally represent distinct species [P. hirstiscls (Fig. 9a-c) and P. ventrensis Coffin, 957 (Fig. 9d-i) (cf. Crain & McLaghlin, 99)] raises qestions regarding the validity of his conclsions. Galatheoidea Far less attention has been directed to carcinization in the Galatheoidea, despite the presence in the grop of a nmber of characters that in pagroids have been identified as attribtes of carcinization. The body forms of galatheoids (Fig. loa-f) vary from the elongate lobster-like Chirostyls Ortmann, 89 and Mnida Leach, 8, throgh the more "sqat lobster" forms of Uroptychs Henderson, 888 and Mnidopsis Whiteaves, 87, to the psedo crab-like Aegla Leach, 8 and crab-like Petrolisthes Stimpson, 858. Freqently early carcinologists failed to recognize the relationships among these three body forms (e.g., De Haan, 85; Dana, 85b). Boas (88b) and Henderson (888) solidified the classification of the Galatheoidea. However, it was A. Milne Edwards & Bovier (89a) who provided the first critical review of what might be evoltionary processes within the sperfamily. Despite Bovier's (89a, b, c) concrrent work to derive the crab-like lithodids from the pagrids throgh a series of morphological analogies, A. > Fig. 9. Pagrs hirstiscls (Dana, 85) (a-c): a, animal in shell (after Schmitt, 9); b, animal removed from shell; c, telson (after Hart, 98). Pagrs ventrensis Coffin, 957 (d-i) (after Crain & McLaghlin, 99): d, shield and cephalic appendages; e, right chelipede; f, left chelipede; g, right second pereiopod; h, left third pereiopod; i, telson. Not to scale.

13 Contribtions to Zoology, 67 () - 997

14 9 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra Milne Edwards & Bovier (89a) explained the morphological variations seen in the galatheoids, for the most part, as adaptations to habitat and depth. For example, the well-calcified cephalothorax and abdomen of "primitive" galatheids were seen by Milne Edwards & Bovier to sggest a certain relation to macrran-like stock, as had been proposed by earlier carcinologists (e.g., H. Milne Edwards, 8). Redction of the abdomen, according to these athors presmably was broght abot by loss of the original primitive fnction of swimming. The similarity of these galatheoids to the symmetrical pylochelids of the Pagroidea sggested to A. Milne Edwards & Bovier (89a) a possible ancestral relationship. However, they speclated that the pagrids had soght ot shelters (crevices or shells) in which to hide their abdomens, ths rendering them soft and asymmetric, whereas the Galatheidae (inclding at that time the Porcellanidae) adapted the postre of folding the abdomen against the sternm. Ths, A. Milne Edwards & Bovier conclded that both adaptive patterns led to redction in the size of the abdomen. Additionally, the porcellanids' preference for shallow-water habitats and seclsion nder stones accentated the abdominal regression, bringing their body form in close alignment with the Brachyra. Ginot (979) specifically noted the tendency of porcellanids toward carcinization. The Aeglidae, becase of their Recent exclsively freshwater habitat, were reviewed only briefly by A. Milne Edwards & Bovier (89a), bt have received considerable scrtiny in recent years by Martin & Abele (986, 988). These for athors agreed that the aeglids exhibited remarkable similarities to pagrids, althogh none related them specifically to the lithodids. The discovery of Hamriaegla glaessneri Feldmann, 98 from the Late Cretaceos of New Zealand tiow places ancestral aeglids in the marine environment. Hippoidea We are not aware of any early athors that actally accredit hippoid morphology to possible carcinization; however, in his revision of the Hippidea, Miers (879) expressed the belief that the hippoids (Fig. log-i) exhibited considerable resemblances to the brachyran oxystomes. Snodgrass (95) made the observation that "when an Emerita Scopoli, 777 is stretched ot at fll length it is seen to be a complete crab". Ginot (979) attribted the similarities of hippoid body form and carapace with varios brrowing Brachyra as another example of convergence. Lomoidea Lomis hirta (Fig. ) shares, with several other anomran families, morphological characters attribtable to carcinization. In his original description, Lamarck (88) placed it in the porcellanid gens Porcellana Lamarck, 8. The lack of oclar orbits, the cylindrical antennlar pedncles, hirste antennal flagellm, and pediform third maxillipedes were among the characters that convinced H. Milne Edwards (87) to establish the gens Lomis for this distinctive animal. Lomis was considered to be related to Lithodes by H. Milne Edwards and most sbseqent zoologists. It was only when this relationship was critically examined by Bovier (89a, 895b) that its distinctiveness was recognized. However, Bovier was convinced that Lomis had evolved from an at least partially asymmetrical ancestor of pagrid lineage. Borradaile (96) considered Lomis a prime example of carcinization. Pilgrim (965), McLaghlin (98a), and Martin & Abele (986) Fig.. Examples of body forms of galatheoids (a, Chirostyls Ortmann, 89; b,mnida Leach, 8; c, Uroptychs Henderson, 888; d, Aegla Leach, 8; e, Mnidopsis Whiteaves, 87; f, Petrolisthes Stimpson, 858), and hippoids (g, Albnea Weber, 795; h, Emerita Scopoli, 777; i, Hippa Fabricis, 787). Species shown: Chirostyls affinis Chace, 9 (after Chace, 9); Mnida schroederi Chace, 99 (after Chace, 9); Uroptychs fornicats Chace, 9 (after Chace, 9); Mnidopsis bermdezi Chace, 99 (after Chace, 9); Aegla platensis Schmitt, 9 (top, side view, after Martin & Abele, 988), and A. schmitti Hobbs, 979 (bottom, dorsal view, after Hobbs, 979); Petrolisthes amoens (Gerin-Meneville, 855) (after Gore, 97); Albnea paretii Gerin-Meneville, 85 (after Williams, 965); Emerita benedicti Schmitt, 95 (after Williams, 98); Hippa testdinaris (Herbst, 79), dorsal (left) and ventral (right) views [after Monod, 956, as Hippa cbensis (De Sassre, 857)]. Not to scale.

15 Contribtions to Zoology, 67 () Albnea Emerita

16 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra g.. Morphology of Lomis hirta (Lamarck, 88). a, c, abdomen, ventral view (after Pilgrim, 965): a, male; c, female; b, whole imal (female), dorsal view, details of left appendages only (after McLaghlin, 98a). Not to scale. reviewed the phylogenetic relationship of Lois with other anomrans. Pilgrim (965) considsd Lomis as representative of a distinct family primitive pagroids, most closely allied to ixtopagrs A. Milne Edwards, 88, as "... an Fshoot from the very base of the Pagridea toither with the Pylochelidae, bt has ndergone e process of carcinization - it is ths the earliest omran to do so". McLaghlin (98a) reeved Lomis to a separate sperfamily (Lomoia); whereas Martin & Abele (986) related the >midae to the Lithodidae as a sister grop of the igroidea. In more recent stdies, Richter & holtz (99) also aligned Lomis with pagids, whereas Tdge (997) sggested a basal igin for Lomis with respect to other anomran ca, based on spermatological evidence. ircinization, an evoltionary reality? smptions iroghot the foregoing commentary, the prem- : has been progressive modification of the omran body form to become more brachyran ib-like. We have reviewed the principal hytheses of carcinization in the Anomra, with iphasis on the Pagroidea. As we have stated fore, Bovier's (89a, c, 895a, b, 897) and Boas' (88a, b, 9) hypotheses are based on the initial spposition that carcinization proceeded as a conseqence of hermit crabs leaving their gastropod shell-shelters and adopting free-living existences. Borradaile's (96) hypothesis follows similar lines; however, he concldes that not all species have the genetic constitents regardless of circmstance. For any of these hypotheses to be tenable, first, the assmption mst be made that hermit crabs initially had membranos abdomens that were protected by se of a sinistral gastropod shell. However, what evidence is there to spport this assmption?. Perhaps that Aristotle fond two species in gastropod shells, and remarked on the softness of their exoskeleton and their clear separation from the shells themselves? Bt then Aristotle spposed that these creatres were generated ot of earth and md (Stebbing, 89). Perhaps in Swammerdam's (77) stdy of Pagrs bernhards, althogh nlike Aristotle, Swammerdam sggested that the shell was secreted by the hermit itself. Bosc (8: 6) introdced his discssion on pagroids saying that "La natre a refse ax crstaces de ce genre les moyens de secrite q'elle a prodige a la plpart des atres; mais elle les a porvs d'ne indstrie qi les en dedommage. En effet, si les pagres ont la partie posteriere d corcelet, et tote la qee, a son extremite pres, deporvs de test, et par con-

17 Contribtions to Zoology, 67 () seqent exposes a tot l'effet des armes de lers ennemis, ils savent garantir ces parties en les enfermant dans ne coqille nivalve. Ce fait a ete conn des anciens, et Test encore de tos les habitans d bord de la mer." A point pon which we can all agree is that tilizing a shell, or some other covering protective of the soft abdomen of most pagroids, confers a srvival advantage. How then cold not owning a shell confer a greater advantage? What the traditional hypotheses of carcinization reqire is either: that a gastropod shell-dwelling hermit crab with a totally membranos abdomen for some inexplicit reason chose to forsake mobility with safety, or that an nexplainable disappearance of shells compelled some hermit crabs to adapt to adverse conditions by becoming free living. We sggest that there is no factal evidence to spport the proposition that hermit crabs were first and foremost shell-dwelling crstaceans, bt rather that comments sch as Bosc's, generated from casal observations of common littoral species, became "fact" throgh repetition. If pagrid morphology is reexamined, Pagrs is the most simplistic of all pagroids, lacking most integmental calcification; having a very redced or virtally nonexistent rostrm; having no sexally modified appendages other than the reglar female egg-bearing pleopods, and having no penes (or sexal tbes), bt sharing with most other hermit crabs a specialized adaptation for hosing stability, i.e., highly developed rasps on the ropods and freqently also on the propodi of the redced forth and fifth pereiopods. For Bovier's (89c, 895b, 897) hypothesis to be plasible, a PagrsAikQ ancestor mst have developed an expanded, well-calcified, and sally well-armed cephalothorax, created a series of calcified abdominal plates, generated a well-developed rostrm, materialized a walking leg from a highly specialized forth pereiopod, and developed a pair of pleopods on the female's first abdominal somite. Granted, in Bovier's hypothesis, abdominal plate calcification took place gradally, as did rostral development, bt conversion of the specialized forth pereiopod to a typical walking leg wold be mch like "the retrn from Eqs to Hymcotherim... a practical impossibility whether the mechanisms are neatly genetic or hazily epigenetic" (Larent, 98). Additionally, like the Lithodinae, the Hapalogastrinae generally have well-calcified carapaces, and most, albeit not all, have paired first abdominal pleopods in females. Boas's (88a; 9) derivation of Lithodes from a Nematopagrs- or Pylopagrs-Wks ancestor reqires more catastrophic morphological changes, althogh paired first abdominal female pleopods are common to both. Despite the fact that Boas' (88a) early "rags to riches" explanation for the transformation of the Pagrs abdomen to the Lithodes abdomen was reinforced by direct comparison of sternal and tergal development in Nematopagrs (Boas, 9), he provided no sbstantive evidence that sch a spontaneos transformation cold actally occr. The general morphological similarities he ascribed to Pagrs, Nematopagrs and Lithodes apply to the majority of the Pagridae. Boas attribted development of the forth pereiopod as a "retrn to the ordinary condition of the Decapoda"; the rostrm simply developed more strongly. Again, reversibility in a complex strctre sch as a walking leg, is considered highly improbable (Rensch, 959), althogh Richter & Scholtz (99) sggest that repetition of genetic information for size and spine pattern of the second and third pereiopods might have shifted posteriorly to be similarly expressed in the lithodid forth pereiopods. The considerable nmber of pagroid taxa now known that have morphological strctres intermediate between a Nematopagrs- Pylopagrs ancestor make Boas' gargantan evoltionary transformation dobtfl. Evidence To find spporting evidence for the existing, or for one or more alternative hypotheses of carcinization, we have compared adlt morphological characters in all the major anomran taxa with a series of characters prported to be indices of carcinological trends. Recent stdies (e.g., Morgan & Forest, 99; Lemaitre, 99, 99; Lemaitre & McLaghlin, 995; Popin & McLagh-

18 96 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra lin, 996; McLaghlin, 997) have enabled s to inclde characters from a nmber of pagroid taxa not available to earlier carcinologists. Althogh we have sed examples from galatheoids, hippoids and Lomis, as well as pagroids, this is not meant to imply that a continm is to be expected. It is qite probable that if carcinization does occr, it does so throgh convergent pathways. Characters Morphological attribtes of carcinization (i.e., eading to or prodcing a brachyran-like crab?ody form) have been compiled from Borne 9), Stevcic (97), and Ginot (979) and nclde 9 categories. Five additional attribtes if those proposed by Richter & Scholtz (99) lave been examined. While or major morphoogical categories have been selected specifically ecase of their presmed evoltionary role in arcinization, the pertinence of individal elelents may not always be clearly evident. For xample, paired first and second male, and paired rst female pleopods wold not appear partictrly relevant. However, the total array of charac- :rs tilized is essential in allowing a clearer picire of evoltionary pathways to emerge. Or assessment of attribtes employs cladistic ethods, bt it mst be pointed ot that not only this only a preliminary and partial analysis, bt so we are aware of the rather nsal applica- >n of cladistics to this stdy. By examining the ssible evoltionary pathways of a set of adlt srphological characters, we are attempting to certain whether or not carcinization in the lomra is an athentic phenomenon rather than termine now the precise phylogenetic relationips among taxa. A thorogh assessment of ;se pathways can only be made when larval and f enile characters are similarly addressed, as y will be in the second part of this review. For or present stdy, we have sed the "otip" concept to root or analysis. In stdies of )ltionary relationships within and among imran taxa, McLaghlin (98b) and Richter Scholtz (99) tilized other anomran and general reptant characters to establish polarities, whereas Martin & Abele (986) sed the character states fond in the pelagic shrimp gens Penaes Fabricis, 798. Neither approach is appropriate to the present investigation. In the first instance, McLaghlin's (98b) assessment was essentially intitive, not a disciplined cladistic analysis. Richter & Scholtz (99) based their ot-grop comparison on information gathered from the Galatheoidea, Hippoidea,. Lomoidea, and other, nspecified reptant decapods. Since we are considering these three sperfamilies in or investigation, they represent components of or overall "in-grop", ths they are not appropriate to serve as ot-grops. Martin & Abele (986) sed Penaes as an ot-grop "becase the characters of the Dendrobranchiata are conceded by most workers to be primitive relative to other infraorders...". This ndobtedly is tre, bt in reviewing Martin & Abele's discssion of characters, we were nable to find any synapomorphies shared by Penaes with the taxa nder consideration that wold qalify it as an ot-grop in or search for evoltionary pathways of carcinization. Rather we have chosen Neoglyphea inopinata Forest & De Saint Larent, 975 as or otgrop. Specific information on N. inopinata has been gleaned from Forest & De Saint Larent (98); interpretation and choice of an ot-grop is based on the gidelines of Nixon & Carpenter (99). That many of N. inopinata's morphological attribtes are plesiomorphic was demonstrated by Poore (99). However, N. inopinata is not a sister grop to the Anomra (cf. De Saint Larent, 979), nor is it considered as "The" ancestor to the Anomra. Nevertheless, the synapomorphy, redction in the length of the fifth pereiopods, shared by N. inopinata and all anomrans spports or choice of it as or ot-grop. Table I provides a smmary of characters and states. Table II frnishes, with N. inopinata as the otgrop, a list of anomran taxa examined and their respective character states. In the discssion that follows, references are made to varios genera, bt it mst be pointed ot that in many cases, particlarly among galatheoid and hippoid taxa, data have been obtained

19 Contribtions to Zoology, 67 () throgh personal examinations of a limited nmber of individal species. When possible, these data have been spplemented with pblished acconts of related taxa. Characters of pagroid genera reflect the overall sense of the genera as crrently interpreted, althogh intrageneric variations do exist. For example, the diogenid gens Pagristes Dana, 85 is characterized by the presence of paired first and second pleopods modified as gonopods in males and paired, similarly modified, first pleopods in females; however, we recognize that there are exceptions. Sch incongrities reflect deficiencies in the alpha level taxonomy of the grops bt do not present any major obstacles to the interpretations of carcinizational pathways. Characters and/or character states. Broadening and flattening of carapace, sternal plates, bccal frame and eventally also the branchial chamber. Six characters are considered in this category, most of which are generally self explanatory. The exception is that of carapace shape. The character states of carapace shape given in this accont may differ significantly from other pblished acconts. For example, Martin & Abele (988) referred to the carapace of Aegla as being extremely depressed, giving the animal an overall flattened appearance, whereas we have scored the Aegla carapace as valted. la - Carapace shape. We have recognized for character states. The primitive sbcylindrical carapace is most closely approached in the hippoid family Hippidae and the similarly sanddwelling Ecerams Stimpson, 86 of the galatheoid family Porcellanidae. It is probable that the brrowing habits of these animals may be as mch a contribting factor to their carapace shape as the possible retention of the primitive character state. Virtally all other anomrans exhibit some more extensive degree of dorsoventral compression of the cephalothorax. We have defined three character states to depict the transition away from the primitive sbcylindrical cephalothorax: () "globlar", in which the cephalothorax sally is not considerably longer than broad, is moderately deep, and has generally ronded carapace margins; () "valted", in which the relatively straight lateral faces of the carapace and branchiostegites provide the impression of-an arciform carapace; () "flattened", representing the state where there is relatively little lateral depth to the cephalothorax. Within the remaining examined pagroid genera, Pylocheles A. Milne Edwards, 88 and Cheiroplatea Bate, 888 among the Pylochelidae, Cancells H. Milne Edwards, 86 among the Diogenidae, and Pylopagrs and Xylopagrs A. Milne Edwards, 88 among the Pagridae, still retain a somewhat sbcylindrical carapace shape; however, it is most probable that habitat preferences have strongly inflenced carapace shape in these genera, rather than retention of the plesiomorphic condition. All generally are petricolos, xylicolos, spongicolos or scaphopod shell dwellers. As may be seen in Table II, the evoltion to a more "crab-like" form is reflected in those taxa in which the carapace is globlar or valted, i.e., Birgs Leach, 85 and Coenobita Latreille, 89 in the Coenobitidae, Pagropsis Henderson, 888 and Tisea Morgan & Forest, 99 in the Diogenidae, the presmably "partially carcinized" Pagridae, Solitariopagrs, Porcellanopagrs, Ostraconots, Alainopagrs, Alainopagroides, Icelopagrs McLaghlin, 997, Labidochirs, and Lithopagrs Provenzano, 968, as well as all of the Parapagridae and Lithodidae. Althogh commonly thoght of as having sbcylindrical carapaces, not all hippoids do exhibit this character. Carapaces of two of the for genera sampled had the more "crab-like" globlar to valted carapace strctre. Representatives of the Galatheoidea are even more variable. In the porcellanids, the carapace is sbcylindrical in Ecerams, bt globlar in Polyonyx Stimpson, 858, and flattened in Petrocheles Miers, 876 and Petrolisthes Stimpson, 858. Carapace shape is seen as globlar in the chirostylid Gastroptychs Callery, 896, bt valted in Uroptychs, whereas in the galatheids the distinction was less definitive. Carapace shape in Galathea Fabricis, 79, Mnida and Mnidopsis is neither globlar, nor valted, bt rather intermediate. As previos-

20 98 PA. McLaghlin & R. Lemaitre - Carcinization in the Anomra Table I. Characters for carcinization analysis. Paragraph nmerals correspond to attribtes of carcinization discssed in text (see Characters and/or character states). Character state symbols are in parentheses. Ot-grop = Neoglyphea inopinata Forest & De Saint Larent; data from Forest & De Saint Larent (98). Abbreviations: mxp, maxillipede; P, pereiopod.. Broadening and flattening of the carapace, sternal plates, bccal frame and eventally also the branchial chamber; la. Carapace shape: sbcylindrical (); globlar (); valted (); flattened (). lb. Rostrm: elongate, broad basally and tapering to acte tip (); elongate cylindrical or sbcylindrical (); long to moderately short, trianglar or sbtrianglar (); yery short, blntly trianglar, ronded, obsolete, or absent (). Ic. Lateral projections (postorbital spines): obsolete or absent (); weakly developed (); moderately well developed (); elongate, prominent (). Id, Sternite of the third maxillipedes: narrow, bases of corresponding appendages contigos or nearly so (); broad, bases of corresponding appendages separated (). e. Sternite of chelipedes (forth thoracic stemite): narrow, bases of corresponding appendages contigos or nearly so (); broadened, bt maximm mch less than half total carapace width, corresponding appendages neither approximate nor very widely separated (); very broad, maximm nearly half total carapace or greater, corresponding appendages very widely separated (). f. Sternite of third pereiopods (thoracic sternite 6): narrow, bases of corresponding appendages contigos or nearly so (); broadened, bt mch less than half total carapace width, corresponding appendages neither approximate nor very widely separated (); very broad, nearly half total carapace or greater, corresponding appendages very widely separated (). Increased integmental calcification: a. Anterior carapace (shield): strongly calcified (); moderately well calcified throghot (); with areas of very weak or no calcification (). b. Posterior carapace: entirely calcified (); posterolateral and/or posteromedial calcification (); entirely membranos or with only scattered small areas of calcification (). c. Branchiostegites: calcified (); partially calcified (); membranos (). Abdomen: i. Abdominal orientation: elongate, straight (); elongate, twisted (); redced, straight or twisted (); redced, folded beneath cephalothorax (). i. Abdominal segmentation; 6 clearly defined somites (); 6 distingishable, bt not clearly defined somites (); fewer than 6 distingishable somites (). :. Tergite calcification: completely calcified (); partially calcified (); membranos or nearly so (). Uropods: Uropod strctre: foliaceos, symmetrical (); specialized, symmetrical (); specialized, asymmetrical (); absent (). Female pleopods: First pleopods: paired and modified as simple "gonopods" (); paired, nmodified (); npaired (); absent (). Second pleopods: paired (); npaired, right or left (); npaired left only (); absent (). Third and forth pleopods: paired (); npaired, right or left (); npaired left only (); absent (). Fifth pleopods: paired (); npaired right or left (); npaired left only (); absent (). Posterior abdominal appendages of males: Third and forth pleopods: paired (); npaired, right or left (); npaired left only (); rdimentary or vestigial (); absent ()- Fifth pleopods: paired (); npaired, right or left (); npaired left only (); rdimentary or vestigial (); absent (). Branchia: Arthrobranch formla: rdiment (mxpl), (mxp), (mxp), (P), (P), (P), (P), (P5) ();,,,,,,, ();,,,,,,, ();,,,,,,, ();,,,,,,, (). Plerobranch formla:,,,,(p), (P), (P), (P5) ();,,,,,,,, ();,,,,,,, ();,,,,,,, ();,,,,,,,, ();,,,,,,, (5);,,,,,,, (6);,,,,,,, (7). Gill strctre: trichobranchiate (); intermediate (); phyllobranchiate (). Antennal scale (acicle/exopod): Antennal acicle: elongate, trianglar, marginally armed (); well developed, cylindrical, or blade-shaped, narmed (); redced (); absent (). Expansion ofischia andmeri of third maxillipedes to form a plate-like covering over the other mothparts: Expansion of ischim and mers: no expansion (); some degree of expansion to partially cover other mothparts (); broadly expanded to form plate-like covering over other mothparts (). Accessory tooth (teeth): with accessory tooth (); withot accessory tooth (); absent (). Oclar orbit development with accompanying redction in the size of the antennles and antennae: Oclar orbits: no orbits developed (); partial development of orbits (); well-developed orbits (). Antennlar and antennal redction: well developed, elongate (); one or other redced (); both redced ().

21 Contribtions to Zoology, 67 () ~ Table I. Cont.. Fsion of last thoracic somite: not fsed to either abdomen or cephalothorax (); fsed to first abdominal somite (); fsed to cephalothorax (). 5. Position of dactyls ofchelipedes: simple (); sbchelate (); chelate, fingers opening horizontally (); chelate, fingers opening obliqely (); chelate, fingers opening vertically (). 7. Development of first two pairs ofpleopods in males: 7a. First pleopods: modified as complex coplatory appendages (); present, not modified complex coplatory strctres (); absent (). 7b. Second pleopods: paired, natatory, with appendix masclina (); paired, modified as coplatory strctres (); npaired, redced (); absent (). 8. Development of male penes: Male gonopores: paired, nmodified (); one or both masked by tft of prominent setae (); one or both with vas deferens prodced as sexal tbe (). Spplemental characters (Stevcic, 97; Wolff, 96b; Richter & Scholtz, 99):. Development of the forth pereiopod: a. Size and strctre of third and forth pereiopods: generally similar (); dissimilar (). b. Ventrolateral margin of propods of forth pereiopod: narmed (); row of spines (); row of corneos scales or tbercles (); mltiple rows of corneos scales or tbercles (). c. Forth pereiopod termination: simple (); sbchelate (); semichelate (); chelate ().. Position and strctre of the fifth pereiopod: a. Fifth pereipod termination: simple (); sbchelate (); semichelate (); chelate (). b. Propods of fifth pereiopod: rows of setae or denticles (); rasp of corneos scales (). ly noted, we consider the aeglid carapace to be valted. The carapace of Lomis, like the galatheids, is neither strictly globlar nor strictly valted. lb. - Rostrm. Among anomran taxa there is a great range of development. An elongate, basally broad, and tapering rostrm, sch as seen in Neoglyphea Forest & De Saint Larent, 975 is considered plesiomorphic, with redction indicative of more advanced conditions. Retention of this type of rostrm in pagroids is seen only in Probeebei among the parapagrids and a few of the lithodid genera. It is redced, bt nonetheless prominent in Birgs. Throghot the Pagridae there is a clear tendency toward redction in rostral length and strength. The rostrm in hippoids is never very well developed, varying from moderately short in albneids to very short in hippids. In contrast, the primitive elongate, trianglar rostrm is seen in Aegla, Mnidopsis, Galathea, and Uroptychs, with only moderately redction in the other galatheid and chirostylid genera. However, the rostrm is moderately short to obsolete in all of the porcellanid genera examined. In Lomis the rostrm is moderately short as well. lc. - Lateral projections. The role of the lateral projections, or post-antennal spines, of the carapace has not been flly investigated for any anomran grop. In some pagroid genera, development of the lateral projections appears to be correlated with carapace calcification, whereas in some of the galatheoids sch as the porcellanids it wold appear to correlate more directly with the development of oclar orbits. Since lateral projections and/or post-orbital spines are lacking in Neoglyphea (presmably plesiomorphic), we have scored their development as apomorphic. Among pagroids, lateral projections are best developed in some of the lithodid genera, and obsolete or entirely lacking only in Cancells, Probeebei and Tylaspis. Among hippoids, galatheoids and Lomis, lateral projections vary from total absence to relatively strong development. Id. - Sternite of the third maxillipedes. In the pagroid genera of the families Pylochelidae, Coenobitidae, and Diogenidae we see the assmed primitive condition of a very narrow sternite, with the corresponding appendages basally approximate, seen. In genera of the Pagridae, Parapagridae, Lithodidae, all hippoids, and galatheoids, as well as Lomis, the bases of the third maxillipedes are separated. However, in Gastrop-

22 P. A. McLaghlin & R. Lemaitre - Carcinization in the Anomra tychs and Galathea, it is the articlating condyles that are separated; the basal segments of the maxillipedes themselves are nearly approximate. le. - Sternite of chelipedes (forth thoracic sternite). While it might be expected that if the bases of the third maxillipedes were approximate, the bases of the following appendage pair, the chelipedes, wold be similarly positioned or vice versa, and this is for the most part tre in pagroids; however, there are exceptions. In the diogenid genera Clibanaris Dana, 85a and Tisea, the chelipedes are separated, while the maxillipedes are approximate. In contrast, in the parapagrids Sympagrs Smith, 88 (sens Lemaitre, 989), Parapagrs Smith, 879, Bivalvopagrs Lemaitre, 99, and Tsnogaipagrs Osawa, 995, and the pagrid genera Enneopagrs McLaghlin, 997, Pylopagropsis Alcock, 95, and Xylopagrs, the chelipede bases are approximate even thogh the maxillipedes are broadly separated by the sternal plate. There does not appear to be any clear correlation between carapace shape and the separation of either third maxillipedes or chelipedes. The sternite of the chelipedes is narrow in all of the hippoids examined, and the chelipedes correspondingly approximate basally. Ths, it wold appear that the breadth of this forth sternite in hippids is not a fnction of carapace shape either: the sternite is narrow whether the carapace is either sbcylindrical or globlar-valted. In all galatheoid taxa examined, the forth thoracic sternite is broad, even in porcellanid genera where the carapace varies from sbcylindrical (Ecerams) to flattened {Petrolisthes and Petrocheles). A similar broadening of this sternite is also seen in Lomis. If. - Sternite of third pereiopods (thoracic sternite 6). In pagroids there does seem to be a relationship between carapace shape and the extent of the broadening of the sternite of the third pereiopods among pagrids and lithodids. With few exceptions, those taxa having globlar or trncate carapaces similarly had very broad sixth sternites. Moderate broadening was seen in Coenobita. That was not the case however, for pylochelids, diogenids or parapagrids. Some taxa sch as Ciliopagrs Forest, 995, with species that occpy the very slender whorls of cone shells, exhibit markedly broad sternal plates, which reflect microhabitat inflence; however, that phenomenon simply indicates the plasticity of hermits to adapt to their environment. Only in the hippoid Blepharipoda Randall, 8 is a modest broadening of the fifth and sixth thoracic sternites seen, which might or might not be associated with carapace shape. In contrast, Lomis and all galatheoids exhibit exceptionally broad sternal plates regardless of carapace shape.. Increased integmental calcification. The three characters considered in this category reflect, in part, the division of the cephalothorax seen in pagroids. With the exception of some lithodids, the pagroid cephalothorax is clearly delineated into an anterior carapace (shield) separated from the posterior carapace by the cervical groove and linea transversalis (It) (Fig. 7a, b). In galatheoids, hippoids, and Lomis, the comparable anterior portion of the cephalothorax is termed the "anterior" carapace. The lateral portion of the carapace (Fig. 7c) that covers the gills (branchiostegite) is well defined in galatheoids, in some, bt not all, pagroids, bt is very poorly defined in some hippoids. We have considered only the degree of calcification of the portions of the carapace, not shape or spination. a. - Anterior carapace. Calcification of the shield in pagroids varies among families and genera. In the Pylochelidae, the shield is sally very well calcified, as it is in coenobitids and diogenids sch as Tisea, Pagropsis, and Cancells. In the Parapagridae, Probeebei, Tylaspis, and Bivalvopagrs all have well-calcified shields, whereas species of the other genera are freqently characterized as having areas of redced calcification. Lithodids all have well-calcified anterior carapaces, while only a few genera of the Pagridae exhibit more than moderate calcification. We have fond only two other taxa among the remaining anomrans that show any redction in calcification of the anterior carapace, Petrocheles and Gastroptychs, and in the case of the latter, this may be an artifact of preservation in the spec-

23 Contribtions to Zoology, 67 () imens we examined. Previos athors (e.g., Baba, 988) make no mention of redced calcification in species of this gens. b. - Posterior carapace. In contrast to the calcification of the shield or anterior carapace in most pagroids, very few exhibit complete calcification of the posterior carapace, except for lithodids. In the Pagridae, completion of calcification is seen only in Ostraconots, and nearly complete in Labidochirs; all other genera have only areas of partial calcification, if at all. Among the Diogenidae, only Tisea, and among the Parapagridae, only Probeebei and Tylaspis have completely calcified posterior carapaces. The posterior carapace is well calcified in Birgs; there is only partial calcification in Coenobita. Little, if any redction in calcification is seen in the remaining anomran grops. c. - Branchiostegites. Calcification of the branchiostegites, when it occrs in pagroids, is most commonly restricted to the oter pterygostomial plate region (optp) (Fig. 7b, c). Exceptions inclde Placetron Schalfeew, 89 among the Hapalogastrinae lithodids and all of the Lithodinae genera, the coenobitid Birgs, and possibly the diogenid Tisea. Some degree of decalcification has been observed in the posterior and/or ventral portions of the branchiostegites in the hippoids Lophomastix Benedict, 9, Albnea Weber, 795, and Blepharipoda, as well as in the porcellanids Petrolisthes and Ecerams, and in Lomis.. Abdomen. The three characters examined in this category pertain only to the general shape and orientation of the abdomen, delineation of the abdominal somites, and the extent to which these have changed from the primitive elongate, straight, well-calcified, six-segmented abdomen of Neoglyphea. Internal symmetry is not addressed, as it does not appear relevant to carcinization; however, asymmetry as it pertains to the abdominal appendages is considered in sbseqent sections. Similarly, the abdominal positioning of organs, sch as seen in pagroids other than lithodids, is not addressed in this analysis. Character c (abdominal tergites -5) embodies character, emphasized by Richter & Scholtz (99). a. - Abdominal orientation. An elongate, straight abdomen is characteristic of the pagroid family Pylochelidae, the pagrid genera Pagritta Melin, 99, Discorsopagrs McLaghlin, 97, Orthopagrs Stevens, 97', Enneophylls McLaghlin, 997, Pylopagrs, Xylopagrs, and a few individal species of other pagrid genera, as well as the parapagrid gens Tsnogaipagrs; most are inhabitants of tblar strctres, sch as hollow pieces of wood, polychaete tbes, scaphopod shells, etc. Exclsive of the Lithodidae and the coenobitid Birgs, elongate, bt twisted abdomens are fond in the vast majority of pagroid genera, reflecting their practice of occpying spiraled gastropod shells. As can been seen in Table II, a few non-lithodid pagroids have simply redced abdomens; however, in these, while there may be a tendency to fold the sixth somite, ropods, and telson ventrally, the abdomen itself is not similarly flexed. In contrast, the lithodid abdomen and that of Birgs are not only redced, bt distinctly folded nder the cephalothorax. In all other anomrans, there is some degree of redction and explicit folding of the abdomen. Among hippoids this is maximized in members of the Hippidae where the elongate telson is firmly pressed against the thorax. In the galatheoids, optimm flexre is seen in the porcellanids. Lomis too has the abdomen folded nder the cephalothorax. b, - Abdominal segmentation. Varying degrees of visible segmentation of the abdomen can be fond among pagroid families and genera. In the Pylochelidae, all six somites are clearly defined as they are in the Coenobitidae. Only in the diogenid Tisea, the pagrids Solitariopagrs and Alainopagrs, and the parapagrid Probeebei can this presmed plesiomorphic condition be clearly observed. In certain other diogenids, e.g., Pagristes, in virtally all other parapagrids, and pagrids sch as Porcellanopagrs, Ostraconots, Pylopagropsis, and Xylopagrs, six somites often can be distingished as slight to appreciable integmental thickenings or at least

24 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra identifiable transverse segmental bands of fibrils. Althogh five clearly delineated segments are common at least to lithodids of the Lithodinae, the first is sally nrecognizable as a distinct somite becase of fsion. Six well-defined abdominal somites are characteristic of the Hippoidea, Galatheoidea, and Lomis; however, there often is appreciable redction in the size of the first somite. c. - Tergite calcification. Again, it is the Pagroidea that manifests dramatic calcification loss. As the data in Table II demonstrate, the primitive condition of strong tergal calcification is seen in members of the Pylochelidae, the coenobitid Birgs, the parapagrid Probeebei, and in some genera of the Lithodidae. According to Lemaitre (995) the strong calcification of the sixth tergite seen in sch pagrid genera as Xy~ lopagrs and Discorsopagrs is clearly an adaptation for tbe closing. Partial calcification is more common among species of the remaining parapagrid genera, the hapalogastrinid lithodids and the pagrids Solitariopagrs, Alainopagrs, and Porcellanopagrs, In the vast majority of diogenids and pagrids, the sixth tergite is weakly calcified, while the remainder are membranos. In contrast, there is little or no sbstantive redction of calcification in the first five abdominal tergites in the galatheoids, hippoids, or Lomis.. Uropods. We have considered the morphological strctre of the ropods only in very general terms. For example, the primitive state, "foliaceos" refers to a biramos appendage in which the rami are broad, flattened, and marginally setose, in contrast to more specialized appendages that are either symmetrical or asymmetrical. In pagroids this specialization takes the form of rasps of corneos spines or scales. Contrary to the rather sweeping statement made by Martin & Abele (986), lithodids are not the only pagroids to lack ropodal rasps. For example, althogh the ropods of the diogenid Pagropsis are, in strctre, typical of other genera in the family, no rasps are present. Uropods are present bt they are very greatly redced in Birgs. The ropods of hippoids are specialized for brrowing, bt are not provided with rasps, whereas all galatheoids retain plesiomorphic foliaceos ropods. The ropods of females of Lomis similarly are foliaceos, while those of the males are vestigial. 5. Female pleopods. We have divided the development of female pleopods into for separate characters, as considerable diversity occrs in the Pagroidea. Pleopods on the first abdominal somite of females in the Anomra occr only in the adlt, and commonly are referred to as gonopods, althogh no sexally related fnction has ever clearly been demonstrated for them. Second pleopods, althogh sally npaired, are symmetrically or asymmetrically paired in some taxa, or rarely are absent entirely. Throghot the anomran genera we examined, the third and forth pleopods were present, either as paired or npaired appendages, specifically adapted for egg carrying. Development of fifth pleopods was variable. 5a. - First pleopods. In Neoglyphea inopinata the paired first pleopods of the female are twosegmented, moderately long appendages. The distal segment is flattened, flagelkform, with the distal portion more or less divided into distinct articles. According to Forest & De Saint Larent (989), these appendages are provided with a relatively precise arrangement of simple, plmose and barbed setae. Paired first pleopods are reported for all genera of the Pylochelidae; those of Mixtopagrs showing annlations (Forest, 987: fig. 75e) reminiscent of N. inopinata. Within the Diogenidae, only in the genera Pagropsis and Pagristes is the development of female first pleopods retained, althogh this condition has been lost in some species of the latter gens. When present, these paired first pleopods are commonly provided with marginal simple or plmose setae, bt appear to lack the complexity seen in N. inopinata or the Pylochelidae. Among the Pagridae, paired first pleopods are developed in several genera, inclding Nematopagrs and all of the PylopagrsAike genera (cf. McLaghlin, 98). However, among those genera considered potential candidates for a pagroid carcinization pathway, only in Alainopagroides are paired first

25 Contribtions to Zoology, 67 () pleopods developed. Paired first pleopods are lacking in all coenobitids. Lomis was the only non-pagroid anomran in which we fond paired first pleopods developed, bt these are rdimentary. 5b. - Second pleopods. Among pagroids, females of all pylochelids and parapagrids of the genera Parapagrs and Bivalvopagrs have paired pleopods on the second abdominal somite; their occrrence is variable in species of Sympagrs (sens Lemaitre, 989) and the right second is well developed or rdimentary in Tylaspis. Unpaired second pleopods can occr on either the right or left side of the abdomen in the diogenid genera Pagropsis and Cancells, bt are restricted to the left side in the remaining diogenid genera, coenobitids, and all of the pagrid and lithodid genera. Female second pleopods are paired in hippoids, many of the galatheoids, and Lomis. They are absent in all porcellanids and some chirostylids, and redced in some species of Mnida and Galathea. 5c. - Third and forth pleopods. Female pagroid third and forth pleopods are paired in the Pylochelidae and the parapagrids Bivalvopagrs and Tylaspis, althogh they become rdimentary with increasing animal size (Lemaitre, in press). In all other pagroids, inclding the lithodids, npaired pleopods occr on the left side only, except in the diogenid genera Pagropsis and Cancells, where npaired pleopods can occr on either side of the body. Paired third and forth pleopods occrred in all hippoids and galatheoids we examined, as well as in Lomis. 5d. - Fifth pleopods. As with the third and forth pleopods, we fond paired female fifth pleopods only in the pagroid family Pylochelidae and the parapagrids Bivalvopagrs and Tylaspis. Unpaired fifth pleopods occr on either the right or the left side in species of the diogenid gens Cancells, bt on the left side only in all other diogenid genera except Pagropsis, where they are absent. Loss of the fifth pleopod is niversal in the coenobitids, and not ncommon in the Pagridae, being observed in Solitariopagrs, Alainopagrs, Porcellanopagrs, Ostraconots, Alainopagroides, Lithopagrs, and Xylopagrs. Unpaired left fifth pleopods were present in all of the lithodids we examined. Fifth pleopods are absent in females of Hippa Fabricis, 787, bt present in other hippoids. Lomis and most galatheoids have paired fifth pleopods, althogh we fond them lacking in Uroptychs pbescens Faxon, Posterior abdominal appendages of males. The occrrence, in males, of paired or npaired pleopods developed on the third throgh fifth abdominal somites is variable, bt when present, these appendages are not modified as gonopods. We have considered pleopod development on the third and forth somites separately from the fifth. 6a. - Third and forth pleopods. Only male pagroids of the Pylochelidae and the parapagrids Bivalvopagrs and Tylaspis have paired third and forth pleopods. These are symmetrical in the pylochelids, bt strongly asymmetrical in the parapagrids. Unpaired left third and forth pleopods are the rle for the other genera of the Parapagridae, except Probeebei where they are vestigial or absent. These are lacking in Birgs, and redced or absent in coenobitids. Similarly, pleopods are completely lacking in the diogenid genera Pagropsis and Cancells, nknown for Tisea, bt npaired on the left in the remaining genera. Loss of third and forth pleopods is characteristic of all lithodids and several pagrid genera and at least one species of Pagrs (see Table II). 6b. - Fifth pleopods. Among male pagroids, paired fifth pleopods are fond only in the Pylochelidae and the parapagrids Bivalvopagrs and Tylaspis. Most commonly an npaired left appendage is present, often somewhat smaller in size than the preceding two. In genera sch as Porcellanopagrs, Solitariopagrs, etc., where the third and forth pleopods are absent, the fifth also is missing; however, this pleopod is occasionally missing in pagrids that retain the third and forth. The fifth, like the forth and third, are absent in all lithodids. The fifth is always absent in coenobitids. Pleopod redction and/or loss is common in male hippoids, porcellanids, and nmeros other galatheoids. They are vestigial in Lomis.

26 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra 7. Union of pterygostomial region of the carapace with the epistome (not inclded in Tables I and II). Sch complete fsion is rarely, if ever, approached in anomran taxa. 8. Adherence of the branchiostegites to the thoracic epimeres (not inclded in Tables I and II). Again, rarely approached in anomrans. 9. Bronchia. We have sed arthrobranch and plerobranch formlae as they have been reported for varios anomran taxa as separate characters, bt have not inclded epipods since their occrrence is restricted to some galatheoids and pylochelids. Gill type is the third character considered. 9a. - Arthrobranchia. Nearly all pagroids are provided with five pairs of arthrobranchs on each side of the body, one pair on the arthrodial membrane of the third maxillipede and one on each of the first for thoracic appendages. There are, however, three genera of the Pagridae in which loss of arthrobranchs has occrred, Enneobranchs Garcia Gomez, 988, Enneopagrs, and Enneophylls. Five pairs of arthrobranchs are present in Birgs and Coenobita, bt those of the third maxillipede and chelipedes are rdimentary and presmably non-fnctional in species of the latter gens. Five pairs of arthrobranchs on each side of the body is also characteristic of all the hippoids and galatheoids examined, as well as Lomis. 9b. - Plerobranchia. The primitive plerobranch condition is represented by a single gill on the body wall between the arthrobranchs of pereiopods two throgh five. Among pagroids, this condition is seen in the Pylochelidae, Birgs, and several genera of the Diogenidae. Generally, when gill loss occrs, it is loss of the plerobranchs, beginning with those of the second and third pereiopods. Most parapagrids have lost all bt the plerobranch of the forth pereiopod; however, some species of Sympagrs (sens Lemaitre, 989) retain a remnant of a gill on the fifth pereiopod as well. Only in some genera of the Pagridae are plerobranchs lost entirely. Plerobranch loss in the hippoids is variable, whereas Lomis and all of the galatheoids we examined retain a fll complement of plerobranchs. 9c. - Gill strctre. Althogh dendrobranchiate gills are considered to reflect the primitive condition, these are thoght to have given rise to the trichobranch gills of reptants (Martin & Abele, 986). Therefore the primitive gill strctre is trichobranchiate for or analysis, and this is the gill strctre of Neoglyphea inopinata (Forest & De Saint Larent, 98) and all pylochelids (Forest, 987). Of the diogenid genera examined, intermediate gills were fond in Pagropsis. Gills in species of Pagristes varied from trichobranchiate to phyllobranchiate, while the latter were common to Clibanaris and Tisea. Phyllobranchiate gills are typical of the coenobitids and the majority of pagrid genera, however, there are genera whose species have either trichobranchiate or intermediate gill types. As far as we know, all lithodids have phyllobranchiate gills. A few hippoids have trichobranchiate gills, others are phyllobranchiate, as are all galatheoids observed. The gills of Lomis are trichobranchiate.. Antennal scale (acicle/exopod). Redction in the length and armatre of the antennal acicle is considered evidence of carcinization; however, major redction in the antennal acicle is observed in relatively few pagroids. It is shortened in Birgs and Coenobita, as well as in diogenid genera sch as Cancells and Clibanaris, and in pagrids sch as Solitariopagrs, Porcellanopagrs, and Xylopagrs. Althogh spination, inclding aciclar development, is strongest in jvenile lithodids, the most significant redctions we observed were in adlts of Paralithodes and Neolithodes. Appreciable redction in the antennal acicle was noted in some of the hippoid genera, the majority of galatheoids, and Lomis (Table II).. Presence of a sella trcica posterior (not inclded in Tables I and II). Althogh cited by Borne (9) as one of the characters of carcinization, a sella trcica is not present in all brachyrans and, to or knowledge has not been identified in any anomrans.

27 Contribtions to Zoology, 67 () Expansion of the ischia and meri of third maxillipedes to form a plate-like covering over the other mothparts. There is considerable variation in the development of the endopod and exopod of third maxillipedes, as well as in setal types; however, only the expansion of the ischim and mers has been correlated to carcinization. We have added as a second character, the presence on the ischim of the tooth-like ridge referred to as the "crista dentata" and the occrrence of one or more "accessory teeth". Neoglyphea inopinata is provided with a prominent crista dentata and several accessory teeth (Forest & De Saint Larent, 98), and we consider this condition to represent the plesiomorphic state, althogh this view is not shared by Scholtz & Richter (995). a. Expansion of ischim and mers. No expansion of the ischim and mers of the third maxillipedes was observed in any of the pagroid genera examined. Minor expansion of these segments was observed in Hippa, bt only in the porcellanids was any noteworthy expansion seen. b.-accessory tooth (teeth). Among the Pylochelidae, Mixtopagrs was the only one of three genera we observed that retained the accessory tooth; however, Forest (987) noted its presence in Pomatocheles Miers, 876 and reported two teeth in Trizocheles Forest, 987 and several in Cancellocheles Forest, 987. We know of no coenobitid, diogenid or parapagrid gens in which the crista dentata is provided with an accessory tooth, althogh the cristate strctre itself is sally well developed. In the Pagridae, the sitation is different. Richter & Scholtz (99) were nsre whether one or more teeth shold be considered plesiomorphic or apomorphic, whereas we have rated its occrrence a plesiomorphic character. While species of the majority of pagrid genera have a well-developed crista dentata and one or more accessory teeth, in a few (e.g., Ostraconots, Enneopagrs, Iridopagrs De Saint Larent-Dechance, 966, and Decaphylls De Saint Larent, 968) the accessory tooth is absent. Additionally, in a few genera the crista dentata itself is redced, occasionally to only one or two teeth. The lithodid Placetron has no accessory tooth on the crista dentata. In hippoids we fond the crista dentata present, bt lacking an accessory tooth in Lophomastrix and Blepharipoda; it is totally absent in the examined species of Hippa and Albnea. Among the Galatheoidea we reviewed, the primitive state was observed only in Aegla. The crista dentata was absent in all porcellanids and in at least one species of Uroptychs; it was present, bt lacking an accessory tooth in Gastroptychs, Galathea, Mnida, and Mnidopsis. Lomis also has a crista dentata, bt no accessory tooth.. Oclar orbit development with accompanying redction in size of the antennles and antennae. a. - Oclar orbits. Development of oclar orbits in pagroids, if sch occrs, is very slight, and limited to a few lithodid taxa (Table II). Among the other anomrans, only the Galatheoidea have weakly or well-developed oclar orbits, most specifically in some species of the Porcellanidae. b. - Antennlar and antennal redction. No appreciable redction in antennlar or antennal size was observed in any pagroid. However, in Birgs and Coenobita the antennles are strongly modified to fnction in the aerial environment. Redction in size, and nmber of segments, particlarly in the antenna, was indicated only in galatheoids, notably in porcellanids.. Fsion of last thoracic somite. Poore (99) rated Neoglyphea apomorphic in the fsion of the last thoracic somite, as in this taxon it is not fsed to the seventh thoracic somite as it is in two of his other ot-grops, Enoplometops A. Milne Edwards, 86 (sometimes considered an axiid) and Nephropsis stewarti Wood-Mason, 87 (a nephropid lobster). Since there is neither fsion between the seventh and eight thoracic sterna in Neoglyphea nor in many of the Anomra, a lack of fsion is considered, for this analysis, the plesiomorphic state. No fsion of the last thoracic somite was apparent in pylochelids, coenobitids, or diogenids. In parapagrids there appeared to be a tendency

28 6 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra toward sternal fsion of the last thoracic and the first abdominal somites in species of most genera, inclding Sympagrs dimorphs Stder, 88, a species scored by Richter & Scholtz (99) as not fsed. Althogh fsion between the sternites of the last thoracic and first abdominal somites is common among pagrids, it is not complete in some genera, e.g., Labidochirs, Phimochirs McLaghlin, 98, and Xylopagrs. In the lithodid gens Cryptolithodes there appears to be fsion of the last thoracic somite with both the first abdominal and the preceding thoracic somites. No fsion of these somites was observed in any of the hippoids, galatheoids, or Lomis. 5. Position of dactyls of chelipedes. The brachyran position of the dactyls perhaps has phylogenetic significance; however, this character presmes a chelate appendage. In N. inopinata the first pereiopods have simple dactyls. Some of the hippids have sbchelate first pereiopods. In pagroids, all first pereiopods are chelate, althogh the manner in which they are carried may vary within any given gens. It is dobtfl that in the Anomra this character contribtes to any meaningfl evalation of the carcinization hypothesis. 6. Females with a receptaclm seminis (not inclded in Tables I and II). No female anomrans that we know of have a receptacle for sperm storage. 7. Development of first two pairs ofpleopods in males. The presence, in TV. inopinata, of paired first male pleopods specialized as gonopods is taken to indicate the plesiomorphic condition. Redction and/or loss of one or both members of the pair is apomorphic, Paired, bt natatory second pleopods are fond in N. inopinata (Forest & De Saint Larent, 98). The specialization of these pleopods followed by redction and ltimate loss are considered apomorphic states. Or view of polarity in these male pleopods is contradictory to the interpretation of Martin & Abele (986). 7a. - First pleopods. Paired male first pleopods modified as gonopods are present in all pylochelids (Forest, 987), in the diogenid genera Pagropsis and Pagristes, and in most parapagrids. The occrrence of paired first pleopods in the Pagridae is rare (e.g., Lithopagrs, Xylopagrs), and has not been reported for any lithodid or coenobitid. Among the other anomrans, paired coplatory first pleopods occr in some galatheoids and Lomis (Table II). 7b. - Second pleopods. No natatory male second pleopods are known in anomrans. In the pylochelids and some parapagrids, these appendages are modified as gonopods, as they are in Pagropsis, Pagristes, and Strigopagrs Forest, 995, bt npaired and nmodified in coenobitids. With few exceptions, second pleopods of pagrids occr only on the left side of the abdomen, if they are present at all. Althogh second pleopods are reportedly absent in all lithodids, we have fond a vestigial left appendage in Rhinolithodes. Second pleopods are absent in hippoids. Among galatheoids, only in Aegla is the second pair redced or absent (Martin & Abele, 988). Lomis also has paired second pleopods modified as gonopods. 8. Development of male penes. No development of penes is reported for Neoglyphea; therefore we consider the presence of paired, nmodified gonopores (lacking extensions of the vas deferens) the primitive condition. Sexal tbes arising from the gonopores as extension of the vas deferens are reported in a nmber of pagroid genera, members of the Hippoidea, and in the galatheoid Aegla (Table II). On the basis of sexal tbe development in the Pagridae, we have rated the presence of distinct tfts of setae masking the gonopores as an intermediate condition, sch as seen in Pagrixs. While no tre sexal tbes are developed in Birgs, there are slight protrsions of the Vas deferens from each gonopore in preserved specimens. At least in some species of Coenobita, the vas deferens is prodced into a well-calcified sexal tbe. 9. Inhalant opening lies primarily before the

29 Contribtions to Zoology, 67 () base of the chelipede (not inclded in Tables I and II). A rare, and most probably analogos sitation occrs in some anomrans.. Calcification oftergites of abdominal somites -5 (see c, not inclded in Tables I and II).. Fsion of basal segments of pper antennlar flagellm (not inclded in Tables I and II). Richter & Scholtz (99) sggested that the basal articles (segments) of the oter antennlar flagellm fse in a characteristic manner in the Pagridae and Lithodidae. However, they examined only six species. They observed similar fsion in two of six diogenid species inspected. Althogh we made no specific effort to determine the degree of fsion in antennlar articles in species of the nmeros genera we examined, casal observation sggests that, while this character may be significant in some phylogenetic applications, it does not appear to be directly related to carcinization.. Displacement of antennlar aesihetascs (not inclded in Tables I and II). Richter & Scholtz (99) similarly proposed that the positioning of the rows of antennlar aesthetascs might demonstrate a phylogenetic relationship among the Pagridae and Lithodidae. Here again, their sample size was too small to permit meaningfl evalation, bt it is dobtfl that this character has any direct application to the present stdy.. Development of the forth pereiopod. Of the three characters considered, two reqire clarification, i.e., the ventrolateral margin of the propods (b) and the termination of the appendage (c). The primitive condition seen in Neoglyphea is a simple amblatory leg with an narmed propodal ventral margin. However, even when the forth pereiopod fnctions as an amblatory leg, the propodal margin may be armed with spines or tbercles. A simple forth pereiopod indicates that the dactyl fnctions as a typical terminal leg segment, analogos to the condition seen in the more anterior amblatory legs. As recommended by McLaghlin (997) and Sandberg & McLaghlin (997), a distinction is made between sbchelate forth pereiopods and semichelate forth pereiopods. In the former, the pereiopod is developed as a prehensile strctre by the folding back of the dactyl against the propods (e.g., Fig. e, f). In the latter, the ventral margin of the propods is prodced beneath the dactyl to sch an extent that flexion of the dactyl becomes mch more akin to the action of a dactyl against a fixed finger of a chelate appendage (e.g., Fig. i-k). A chelate forth pereiopod has the propods developed into a characteristic "fixed finger", with which the dactyl fnctions as a tre chela. a. - Size and strctre of third and forth pereiopods. As in N. inopinata, the forth pereiopod is elongate and strctrally similar to the third pereiopod in lithodids, galatheoids, hippoids, and Lomis. The forth pereiopod in all these taxa (Fig. a, c, d) fnctions as a walking leg, with a simple terminal dactyl, except in the hippoids (Fig. b) where it is specialized, like the third, for brrowing. In Birgs, the forth pereiopod is approximately one-half length of the third, armed with scattered small spines or spinles, bt not amblatory. In all non-lithodid pagroids, the forth pereiopod is redced and differs sbstantially from the third (Fig. e-o). b. - Ventrolateral margin of propods of forth pereiopod. The ventrolateral margin of the propods in lithodids and galatheoids may or may not be provided with row(s) of spines. This margin is also armed in Lomis, bt typically narmed in hippoids. In many, bt not all non-lithodid pagroids, this propodal margin may be specialized to form a propodal rasp of one to several rows of corneos spines or scales, often extending onto the lateral face (Figs. h-k, a-e). However, it is narmed in Birgs, in the diogenid Pagropsis, in the parapagrids Probeebei (Fig. f) and Tylaspis (Fig. g), and in the pagrid Ostraconots (Fig. e). The rasp of Alainopagroides consists of two or three small corneos scales or spines (Fig. g). c. - Forth pereiopod termination. The forth pereiopod terminates simply in all lithodids, galatheoids, hippoids, and Lomis. Martin & Abele's (986) general statement that in all her-

30 8 P. A. McLaghlin & R. Lemaitre - Carcinization in the Anomra Fig.. Forth pereiopods of varios anomrans: a, Lithodes confndens Macpherson, 9S8 (after Macpherson, 988); b, Ementa talpoida (Say, 87); c, Galathea consobrina De Man, 9 (after Baba, 988); d, Petrolisthes heterochros Kropp, 986 (after Kropp, 986); e, Ostraconots spatlipes A. Milne Edwards, 88 (after A. Milne Edwards & Bovier, 89); f, Solitariopagrs profnds Trkay, 986 (after Trkay, 986); g, Alainopagroides lemaitrei McLaghlin, 997, propods and dactyl (after McLaghlin, 997); h, Porcellanopagrs sp.; i, Tomopagms wassi McLaghlin, 98 (after McLaghlin, 98); j, Pagrs trigonocheirs (Stimpson, 858) (after McLaghlin, 97); k, Xylopagrs tayrona Lemaitre & Campos, 99 (after Lemaitre & Campos, 99);, Mflidopagrs macrocheles (A. Milne Edwards, 88) (after Provenzano, 97); m, Alainopagrs crosnieri Lemaitre & McLaghlin, 995 (after Lemaitre & McLaghlin, 995); n, o, Decaphylls barnajaya McLaghlin, 997, left (n) and right (o) propods and dactyl (after McLaghlin, 997). Not to scale. mit crab families the forth leg is sbchelate, albeit barely so in some, is. not entirely accrate, even when the term semichelate is sbstitted for their "sbchelate". Among non-lithodid pagroids, it is also simple in the pagrid genera Mnidopagrs A. Milne Edwards & Bovier, 89 (Fig. ), Alainopagrs (Fig. m), and Decaphylls (Fig. n). It is trly sbchelate in

31 Contribtions to Zoology, 67 () ~ Fig.. Forth pereiopods of Parapagridae: a, Strobopagrs gracilipes (A. Milne Edwards, 89); b, Sympagrs popini Lemaitre, 99 (after Lemaitre, 99); c, Oncopagrs cidaris Lemaitre, 996 (after Lemaitre, 996); d, Sympagrs dimorphs (Stder, 88); e, Parapagrs sp.; f, Probeebei mirabilis Boone, 96b; g, Tylaspis anomala Henderson, 888 (after Lemaitre, in press). Not to scale. Solitariopagrs (Fig. f), and chelate in Birgs and the diogenid Pagropsis.. Position and strctre of the fifth pereiopod. A character that nites the Anoimira as a monophyletic entity is the redction of the fifth pereiopod, and presmably its position in the branchial chamber for gill cleaning (Scholtz & Richter, 995). The exception, according to these athors, is fond only in shell-dwelling pagroids. There is nqestionably a significant redction in fifth leg size in all anomrans, bt that all non-shell inhabiting anomrans carry the fifth legs within the branchial chamber is not as niversal as these athors sggest. Among the small sample of galatheoids we examined, it is qestionable whether Galathea rostrata A. Milne Edwards, 88 actally carries the fifth leg in the branchial chamber; species of Uroptychs and Chirostyls probably do not, and it is certain that the porcel-

32 P. A. McLaghlin & R. Lemaitre - Carcinization in the Anomra lanid Petrocheles spinoss Miers, 876 does not. Neither do non-shell inhabiting pagroids, sch as species of Pagropsis and Tisea among the Diogenidae, Ostraconots, Porcellanopagrs, Solitariopagrs, Alainopagrs, and Mnidopagrs among the Pagridae, and Bivalvopagrs and Tylaspis among the Parapagridae, althogh Probeebei and the coenobitid Birgs appear to do so. The dactyls and propodi of the fifth pereiopods of Neoglyphea inopinata are very distinctively developed and carry a variety of precisely implanted setal types (Forest & De Saint Larent, 98), and while these appendages are not carried nder the carapace this might simply be attribtable to the shortness of the branchiostegites, which appear to jst cover the gills. Conseqently, it is eqally possible that the plesiomorphic state for the redced fifth pereiopod is one of a gill cleaning fnction. Becase of polarity ambigity we have not inclded this character in or analysis. Like the more anterior appendages, we have scored the simple termination of the fifth pereiopods plesiomorphic, and chelate the most advanced. The presence of setae or denticles on the propods of the fifth pereiopod is jdged more primitive than the development of a rasp of corneos scales. a. - Fifth pereiopod termination. Forest (987) reported that pylochelids had "more or less" sbchelate fifth pereiopods. Jdging from his figres (Forest, 987: fig. 7a-f) he sed the term sbchelate to reflect both trly sbchelate and semichelate conditions. He did not figre this appendage for Cheiroplatea, which we score as tending toward a chelate condition. Chelate fifth pereiopods were fond in all of the diogenid genera we examined, whereas in some parapagrids this appendage terminated in a semichelate strctre. Among pagrid genera, the fifth pereiopod is sbchelate in Solitariopagrs and Alainopagrs, semichelate in Porcellanopagrs and nearly so in Alainopagroides, and chelate or nearly so in the other genera and species examined (Table II). In all other anomrans investigated it is chelate. b. - Propods of fifth pereiopod. Propodal rasps are present, in varying degrees of complexity, in most pagroid genera. Exceptions inclde Birgs among the Coenobitidae, Tisea among the Diogenidae, Probeebei and to a lesser extent Tylaspis of the Parapagridae, and all the Lithodidae. Richter & Scholtz (99) reported that among the Lithodidae, Hapalogaster lacked a rasp, bt Lithodes maja (Linnaes, 758) had a vestigial rasp. We fond no lithodids with a rasp on the propods of this appendage. However, in some cases where setae had been broken or worn off, the setal pores did give the sperficial impression of a minte rasp. Pohle (989) described the propodi of the fifth pereiopods of lithodids as being provided with for types of setae, inclding some described as toothed. Discssion Withot dobt, characters associated with the proposed carcinization phenomonon are present in all anomran major taxa. However, they are more discernible in the Pagroidea than in either the Galatheoidea or Hippoidea, and the former grop will be the focal point of the following discssion. A corollary to the carcinization hypotheses of virtally all previos carcinologists has been the concept that hermit crabs, for some reason, left the shelter of their gastropod shells for a free existence, which in trn "awoke" genetic mechanisms that broght forth varios aspects of carcinization. While this is an interesting theory, it is fonded on the premise that those crabs that nderwent carcinization evolved from hermits that were first and foremost asymmetrical animals that inhabited gastropod shells. The qestion of asymmetry has not been introdced to this point in or consideration of characters of carcinization, except in relation to pleopod loss. Pagroid asymmetry, in its most observable forms, is seen in neqal chelipedes, neqal specialized ropods, and the absence of pleopods on the right side of the body. Nonetheless, a sbstantial nmber of pagroid genera have eqal or nearly eqal chelipedes. Nmeros genera also have eqal, and in a few cases, completely nmodified ropods. In other genera, ropod asym-

33 Contribtions to Zoology, 67 () metry may be a fnction of habitat (cf. McLaghlin & Gnn, 99). Bovier (9: ) viewed pagrid symmetry as being represented by two series of pagroids: the first, the "primitive", symmetrical Pylochelidae, and the second, those pagroids that possessed paired first and second abdominal pleopods. He proposed that asymmetry evolved, throgh shell se, in the second series, bt symmetry was secondarily re-acqired, albeit imperfectly, in those pagroids that achieved a crab-like form. The Pylochelidae are almost exclsively symmetrical, and have been placed between the Thalassinidea and asymmetrical pagrids by many carcinologists (e.g., Stebbing, 89; Borradaile, 96; Wolff, 96b). The exception is the monotypic sbfamily Mixtopagrinae, represented by Mixtopagrs A. Milne Edwards, 88, which is asymmetrical and tilizes a gastropod shell. Bovier (9) considered Mixtopagrs paradoxs intermediate between his two series. Forest (987) has demonstrated that althogh symmetrical in virtally every sense of the word, the pylochelids morphologically are not primitive pagrids, at least in an ancestral connotation. It is or belief that their origin was a neotenos one that will be discssed in greater detail in the larval segment. Martin & Abele (986: 595) made the statement that "the pleopod of the female first abdominal somite has been lost in many anomrans". Richter & Scholtz (99) fond correlations between an asymmetrical abdomen and pleopod loss, bt considered "the sitation regarding the st and nd pleopods more complex". It is of primary importance to point ot that in the Anomra, pleopods do not occr on the first abdominal somite in either sex nless they arise in the matring adlt as sexally modified appendages. The concept that paired first pleopods are lost throgh shell se is incorrect. These gonopods are never developed in either sex in many genera, inclding several non-shell dwelling pagroids, e.g., Solitariopagrs, Alainopagrs, Porcellanopagrs, and Ostraconots. Similarly, paired second pleopods, present in megalopae, are sally redced or lost prior to the development of adlt coplatory appendages in males, and are freqently absent on both sides in genera where coplatory appendages do not develop. The absence of right pleopods remains as the principal example of asymmetry. The proposition that this pleopod loss is a direct reslt from the habit of many pagroids to occpy dextral gastropod shells seems simple enogh to the casal observer, bt is that really tre? Despite the absence of convincing experimental evidence to explain how se of dextral shells by hermit crabs cold lead to loss of pleopods on the.right side, these crstaceans have become a long-standing classical example of how habitat can inflence body plan (e.g., Henderson, 888; Perez, 9; Bovier, 9; Rssell, 96). This traditional interpretation, however, was challenged by Rabad (9), based on detailed observations of the behavior of varios hermit crab species vis-a-vis their shell hosing. He categorically conclded that the traditional interpretation of pleopod loss, as well as other changes presmably broght abot by shell se (e.g., handness, migration of internal organs to the abdomen, abdominal msclatre, decalcification), are nsbstantiated. It shold also be noted that not all pagroids loose (or fail to develop) the pleopods of the right side. Asymmetrically paired pleopods are reported in the parapagrids Bivalvopagrs and Tylaspis, and in other parapagrids total loss of right side pleopods is not niversal. The diogenids Pagropsis and Cancells have no npaired male pleopods, bt those of the female can occr on either the right or the left side. While it is abndantly clear that we still can not adeqately explain the overwhelmingly more freqent occrrence of npaired left pleopods, it is eqally clear that what might appear to be the obvios explanation might not be the accrate one. For example, Sandberg & McLaghlin (997) report that pleopods are completely absent in very jvenile Lithodes maja, and development of pleopods on the left side in females is preceded by slight asymmetry of the abdomen; female gonopods develop considerably later. These athors sggest that abdominal asymmetry and asymmetrical pleopod development may simply be a fnction of egg bearing. Given the fact that male lithodids have symmetrical ab-

34 PA. McLaghlin & R. Lemaitre - Carcinization in the Anomra able II. List of taxa (59) and characters (7) sed in the analysis. Nmerals are the same as for characters in Table I and text (see Characters and/ character states). Character states: -7; missing data: "?". Nmbers separated by dash indicate mltiple character states. Character ixon logijpnea mopinata Kilobit* rgi locbclcs eiroplatea litopagrs gropsfa BUristes incell ibaoaris KB obeebce laspis mpagrm rapagrs 'alvopagri nogaipagrtis litarlopagrs tfaopagrs rcellanopagrs traconott linopagroidm lopagrs ;rodes cbclopagrs matopagrs iopagnrs aeopagrs opagnropsbi lopagors Mdocblri opagn itnochlrns ;n bcrnbardi ;rs pridcai [logaster iignaths cetron olltbodts alithodes bodes ililhodcs alomb ptolltiodes is >pa bomastrfox nnta pharipoda :a :eraml -ollstho rochclcs fonyx troptychs ptychs atfaea oida nldopsts la lb c Id - - le 7 I If U - -? a b c - - a (J I I t b c O-l - - I O-l 5a - 5b - 7 5c "? 5d V? 6a b

35 Contribtions to Zoology, 67 () Table II. Contined. Character Taxon Neoglypnta Inoplnata Coenobite Birgi Pylochdea Cfaeiroplatea MJxtopagrs Pagropsis Pagr isles Canceling Clibanarls Tisea Probecbel Tylaspls Sympagrs Parapagrs Bivalvopagrs Tsnogaipagrs Solitariopagrt Alainopagrs Pored Ian opag ri Ostraconots Alalnopagroldes Icelopagrns Pagrodea Michclopagnrs Ncmatopagn Pylopagn Enneopagn Pylopagroprfi Xylopagn Labldocblrs Litbopagn PbiraocUm* Pagnn bernbards Pagn prideax Hmpalog aster Oedignatbs Plantren Rbinolithodes Paralitbodcs Lithodei Neoltthodes Paralomls Cryptolitbodes Lorn is Hippa Lophomastrix Albiraea Blepbaripoda Aegla Ecerams Petrollsthes Pctrochetea Polyonyx Gastroptycbs Uroptychs Galatbea Mnida Mnidopsls 9a 9b o t s I c Q io a b a V b a V % - - 7a 7-7 7b? a b c - a V

36 PA. McLaghlin & R. Lemaitre - Carcinization in the Anomra domens and no pleopods, their proposition may well have merit. As in lithodids, males of Porcellanopagrs, Ostraconots, Alainopagroides, Solitariopagrs, and Alainopagrs completely lack pleopods; those of the female develop as egg-bearing appendages on somites two throgh for, bt only in Alainopagroides are gonopods developed. Unfortnately, complete nderstanding of pleopod presence and/or absence in pagroids is dependent pon a knowledge of pleopod development in megalopae and jveniles. This will be discssed in greater detail dring or sbseqent presentation of larval evidence. Carapace shape and integmental calcification In terms of carapace shape and integmental calcification, the Lithodidae, and particlarly the sbfamily Lithodinae, are considered the most carcinized. Correspondingly, in these same characters they rank among the more plesiomorphic (Table II). If one examines a series of pagrid genera, a distinct pattern of calcification loss can be observed from the well-calcified Solitariopagrs, Porcellanopagrs, Ostraconots, throgh the slightly less calcified Alainopagrs, Alainopagroides, Pagrodes, and contining throgh Labidochirs and Xylopagrs to eventally genera sch as Michelopagrs McLaghlin, 997, and Pagrs, The primary method by which the cticlar integment is hardened is throgh calcification in which calcim salts are deposited in the organic matrix of the cticle (Stevenson, 985). It is beyond the scope of this commentary to discss calcification in any detail, and the reader is referred to the reviews by Stevenson (985) and Goffinet & Jeniax (99) for specific information and references. Sffice it to say here that calcim needed for cticlar growth is spplied in part throgh diet (e.g., Lafon, 98) or absorption from the ambient water (e.g., Miyazaki & Jozka, 96). The diet of the lithodid Paralithodes camtschatica in the eastern Bering Sea consists of foods rich in calcim, i.e., mollsks and echinoderms (McLaghlin & Hebard, 96), whereas pagrids and diogenids, as far as known, are macrophagos and detritivore scavengers (e.g., Knze & Anderson, 979; Schembri, 98). If one accepts the plesiomorphy of integmental calcification, it might be hypothesized that a lack of availability of calcim-rich foods was instrmental in triggering the onset of an evoltionary pattern of integmental decalcification. Abdominal modifications While a well-calcified abdomen with distinct tergal plates is a primitive character state, redction and folding of the abdomen, on the contrary, is considered, in this review, an advanced condition. However, as well pt by Glaessner (957), an abdomen when not fnctioning as a swimming organ impedes normal mobility of benthic animals that possess a rigid carapace. It wold seem that there might well be an advantage to a lithodid not to have to carry a large, heavily plated abdomen in a posteriorly extended position, particlarly if its appendages were no longer available for locomotion. Stdies of jvenile king crabs indicate that they initially are not free-roaming, bt spend nearly their entire first year in rock crevices and other protective niches (Powell, 97). It is qite reasonable to sspect that by tcking the abdomen beneath the body, ths exposing the calcified abdominal terga to the rogh sbstrate, the crab wold be less likely to sstain injry to its membraneos sternal region. Althogh folding of the abdomen beneath the cephalothorax is an apomorphic character, the development of the elongate abdomen of a typical pagrid is not viewed here as an atavism. Consider the event of a potential calcim loss discssed above, followed from the Lithodinae throgh the Hapalogastrinae, via the first eight pagrid genera cited in the section on carapace shape and integmental calcification, to the typical pagrid with an entirely membranos abdomen virtally devoid of segmentation. Concrrent with the loss of calcified plates wold be increased absorption of flids to maintain body trgor, as is seen in the blbos abdomens of species of the Hapalogastrinae, and Porcellanopagrs, Alainopagrs, etc., among the pagrids. The elongation of the abdomen then well might be jstifiably be considered an adaptation to shellliving. That this pagroid abdomen is not a phy-

37 Contribtions to Zoology, 67 () logenetic reappearance of the elongate abdomens of other reptants is demonstrated by the fact that in pagroids (except lithodids) the reprodctive organs and elements of the hepatopancreas are located there, a condition not fond in other decapods (McLaghlin, 98). Forth and fifth pereiopods All anomrans have redced fifth pereiopods that may, or may not be carried nder the carapace. However, among pagroids, only the lithodids have retained the forth pereiopod as a walking leg. The presence of this primitive character was considered an atavism by Boas (9), and possibly an example of a posterior shift in genetic information for size and spine pattern of anterior leg by Richter & Scholtz (99). Spportive evidence for the latter claim may have inadvertently come from McLaghlin (98b) who cited Harms (9, 98) and Wolff (96b) when she reported, sight nseen, that "Birgs abandons its shell shelter, ndergoes a moderate degree of carcinization, and takes p a free-living existence. With these changes the forth pereiopods grow and take on an amblatory fnction". Now having personally examined Birgs, we can report that its chelate forth pereiopods cannot be eqated to the amblatory forth legs of the lithodids, bt rather represent a specialization for its terrestrial life-style. The forth pereiopods in Probeebei and Tylaspis are nqestionably redced, and when compared with the exceptionally elongate second and third pereiopods, seem markedly so. However, both are simple appendages withot rasps on the propodi and with claw-like dactyls. A pattern of specialization can then be followed. The propods of the forth pereiopod in Ostraconots is greatly expanded into a flattened, ovoid strctre; the lateral face is covered with minte granles. The forth pereiopods in Solitariopagrs show a hint of a propodal rasp in having three clbshaped and three spiniform stiff bristles on the ventral srface. Alainopagroides has only two or three small scales, while Alainopagrs has a row of small, simple spines. Frther modification is seen in Porcellanopagrs where the ventrolateral margin has a row of corneos scales. The propodal rasps of the forth pereiopods are most freqently thoght of as "friction pads" of scales (Rssell, 96); however, the single row of propodal scales in a sbstantial nmber of pagrid genera, as noted above, cold not provide mch friction. Persal of Table II will show that even among or small sample, the propods of the forth pereiopod qite commonly is provided with only a single row of corneos spines or scales, not the mltiple-row rasp familiar to investigators of many of the shallow-water species. Althogh the redction in the forth pereiopods and development of propodal rasps may not appear directly related to carcinization, both are additional morphological attribtes demonstrating an evoltionary trend away from the primitive elongate and simple appendage to a redced and highly specialized one. Habitat Crypticism or protectionism is characteristic of nearly all pagroids except adlts of the larger and more mobile genera of the Lithodinae and Probeebei, and for good reason. An even partially calcified or chitinized integment cold be fatally vlnerable. Members of the Hapalogastrinae are commonly fond in rocky crevices, as are species of some non-lithodid pagroid genera. Other pagroids have adapted to a host of available protection mechanisms. For Solitariopagrs and Porcellanopagrs, a clam shell serves the prpose nicely. For Pagropsis its chelate forth pereiopods, and for Mnidopagrs its spinose ropods, enable them to conveniently carry an anemone above their vlnerable abdomens, althogh this is not necessarily an obligate relationship (Provenzano, 97). Pieces of wood provide an excellent shelter for Xylopagrs species, as do scaphopod shells for Pylopagrs and members of other genera. None of these protection devices reqire asymmetrical ropods or twisting of the abdomen. In fact, for some, there has been no need for propodal rasps either. With its greatly redced abdomen, Labidochirs splendescens makes very good se of small gastropod shells that are readily covered by a growth of hydracti-

38 6 P.A. McLaghlin & R. Lemaitre - Carcinization in the Anomra nias. Its simple forth pereiopods that are rarely able to be carried within the small shell are each provided with a small and relatively insignificant rasp, practically obscred by long setae. Bt for the vast majority of pagroids, what better safegard cold there be than abandoned gastropod shells to provide a movable shelter? The concept that shell resorces are limiting factors for certain hermit crab poplations is ndobtedly accrate, particlarly in the often stdied intertidal poplations (see Elwood & Neil, 99 for review). However, as reported by Dris (99), lack of available shells sally reslts in selection of a variety of alternative shelters. From the evidence presented, we can find no spporting data indicating that this limitation wold case pagroids to evolve a crab-like body form. Cladograms Initial application of PAUP. to the entire morphometry matrix reslted, as might be expected, in a staggering nmber of 7, trees of 69 steps when the analysis was halted. We illstrate (Fig. ) a majority rle consenss tree. The majority rle provides a good overall idea of which taxa form clades. One can ths see the direction of evoltionary pathways, althogh, as indicated earlier, these are only reslts of a preliminary and partial analysis of the total array of possible data. The patterns of relationships among pagroid genera here does not spport the traditional view that evoltionary pathways proceeded from pagrids to lithodids, bt rather the reverse. The exception is the Pylochelidae, which in this context appear primitive. However, this is not srprising, since the evoltionary pathways being investigated are only pathways of carcinization. The pylochelids exhibit few, if any, characters associated with carcinization. An alternative hypothesis With the addition of a nmber of morphologically intermediate pagroid genera, it is clear that carcinization cold not have provided a direct transition from a Pagrs-like gens to Lithodes. Nor Majority rle 6J i 96l 97^, (85) ' [95 8 E7 Neoglyphea fnoplnata j Cheiroplatea ^[leiropiait 9?i Pylocheles Mixtopagrs Lomls Galathea Mnlda Gastroptychs Mnldopsls Uroptyctis Ecerams Petrol st hes Petrocheles Poly on Ix j Albnea 9I Lophomastrix I Blepharipoda Hip pa Aegla Hapalog aster Oedlgnaths Placetron CryptoHthodes NeoUthodes Paralllhodes Lithodes Rhlnolltttodes Paralomls Probeebei Birgs Tlsea Coenoblta Pagropsls Can eel I s Xylopagrs Pagristes Tsnogal pagrs Tyiaspis Bivalvopagms Sympagrs Parapagrs Porcellanopagrs Solitariopagrs Alatnopagrs Osiraconols Alalnopagroldes Labldoclifrs Li Iho pagrs Pagrs prideax Cilbanarls Pagrs bemhards Icelopagrs Pyiopagropsls Pagrodes Enneopagrs Mich elopag rns Nerrtalopagfs Pylopagrs Prtlmochims Fig.. Cladogram of anomran taxa generated by majority rle consenss (* = lithodid clade). does the evidence sbstantiate even gradal carcinization of a membranos, otstretched pagrid abdomen to ltimately prodce the calcified, strongly flexed abdomen of the Lithodinae. However, a Bovierian transition, if viewed in reverse, may present a viable hypothesis to corroborate a relationship between pagrids and lithodids. Certainly there is no single and direct pathway from lithodid to pagrid, nor is there any particlarly cogent one. However, transition from a "crab-like" body form to a "hermit-crab" body form does appear feasible and cold probably have inclded the following events:. Gradal change in the adlt carapace shape

39 Contribtions to Zoology, 67 () from a crab-like, entirely calcified lithodid cephalothorax, throgh varios phases of decalcification to the ltimate weakly calcified, generally flattened carapace of Pagrs-like genera.. Gradal redction in the rostrm from the well-developed, freqently spiniform lithodid rostrm that sally overreaches the eyes, to markedly redced and/or obsolete rostra of other pagroids.. Relaxation of abdominal somites three to six from their strong application against the sternm in the Lithodinae, throgh gradal loss of calcification in the abdominal integment, with concrrent redction and finally obliteration of segmentation and accompanying increases in msclatre to maintain trgidity throgh hydrostatic pressre.. Elongation of the now soft abdomen to better accommodate shell sage, with concrrent migration of elements of the reprodctive and digestive systems into the abdomen. 5. Decrease from three pairs of well-developed amblatory legs to only the first two pairs retaining an amblatory fnction, bt with parallel, albeit gradal, redction and specialization of the third (forth pereiopod). 6. Gradal redction and/or loss in paired first female pleopods adapted for sexal or egg-carrying fnctions (cf. Pohle, 989). Carcinization, if meaning only acqisition of a crab-like body form, mst be acknowledged as a fact. However, carcinization in the sense of Boas (88a, b, 9), Bovier (89a-c, 895a, b, 896, 897) and sbseqent athors, meaning the evoltion of a crab-like body form from a shelldwelling pagrid is, in or opinion fictios, not factal. Contrary to the hypothesis of Cnningham et al. (99), the "king" (Paralithodes camtschatica) did not arise from a hmble hermit heritage. Rather it were lithodids that began to experience integmental calcim loss, for reasons that at this point can only be hypothesized. It then follows that pagroids, over time, left the concealments common-place to the Hapalogastrinae. Some covered the now somewhat soft abdomen with objects sch as halves of bivalve shells (e.g., Porcellanopagrs, Solitariopagrs), anemones (some parapagrids, Pagropsis, Mnidopagrs, etc.). Others contined to se reclsive rock or coral shelters (e.g., Pagritta, Cancells), and even sponges (cf. Sandford, 99), while developing specialized adaptations. However, with the adoption of gastropod shells, hermit crabs gained not only a vastly more abndant concealment resorce, bt were provided greatly enhanced mobility, and with that, profond and rapid speciation. Acknowledgements We are deeply indebted to Dr. Robert H. Gore for allowing s to se him as a "sonding board" for or ideas. Galatheoid specimens were kindly provided by the late Janet Haig. The reviews of Drs. J.S. Bckeridge, UNITEC University, Ackland, A.W. Harvey, American Msem of Natral History, R.C.L. Pilgrim, University of Canterbry, Christchrch, F.R. Schram, University of Amsterdam, and an nknown reviewer were most helpfi and are grateflly acknowledged. Prof. Schram and staff of the Institte for Systematics and Poplation Biology, University of Amsterdam are also thanked for having rn the cladistic analyses. This is a scientific contribtion from the Shannon Point Marine Center, Western Washington University. References Alcock, A., 95. Anomra. Fasc. I, Pagrides. Cataloge of the Indian decapod Crstacea in the collections of the Indian Msem, : i-xi, -97 (Indian Msem, Calctta). Baba, K., 988. Chirostylid and galatheid crstaceans (Decapoda: Anomra) of the "Albatross" Philippine Expedition, Researches Crst., Spec. No. : -. Bate, C.S., 888. Report on the Crstacea Macrra dredged by H.M.S. Challenger dring the years In: Report on the scientific reslts of the voyage of H.M.S. Challenger dring the years Zoology, (5): i- xc, -9. Benedict, J.E., 89. Preliminary descriptions of thirty-seven new species of hermit crabs of the gens Epagrs in the U.S. National Msem. Proc. U.S. natn. Ms., 5: -6. Benedict, J.E., 895. Descriptions of new genera and species of crabs of the family Lithodidae with notes on the yong of Lithodes camtschatics and Lithodes brevipes. Proc. U.S. natn. Ms., 7: Benedict, J.E., 9. The hermit crabs of the Pagrs bernhards type. Proc. U.S. natn. Ms., : Benedict, J.E., 9. A new gens and two new species of crstaceans of the family Albneidae from the Pacific Ocean; with remarks on the probable se of the antennlae in Albnea and Lepidopa. Proc. U.S. natn. Ms., 7: Blackstone, N.W., 989. Size, shell-living and carcinization

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