Introduction. Methods. AMEGHINIANA (Rev. Asoc. Paleontol. Argent.)- 37 (4): Buenos Aires, ISSN

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1 AMEGHINIANA (Rev. Asoc. Paleontol. Argent.)- 37 (4): Buenos Aires, ISSN Catalogue of non-mammalian cynodonts in the Vertebrate Paleontology Collection of the Instituto Miguel Lillo, Universidad Nacional de Tucuman, with comments on species Fernando ABDALN Resumen. CATALOCO DE CINODONTES NO-MAMALIANOS DE LA COLECCI6N DE PALEONTOLOC1A DE VERTEBRADOS DEL INSTITUTO MIGUEL LILLO, UNIVERSIDAD NACIONAL DE TUCUMAN, CON COMENTARIOS SOBRE LAS ESPECIES. Se presenta Ia lista comentada del material de cinodontes no-mamalianos depositados en Ia colecci6n de Paleontologfa de Vertebrados del Instituto Miguel Lillo (PVL) de Ia Universidad Nacional de Tucurm1n. Esta es Ia colecci6n mas importante de tetrapodos triasicos sudamericanos. El ordenamiento se realiz6 a nivel de familia con comentarios sobre Ia distribuci6n en el mundo y su integraci6n. Se presenta tambien informacion sobre el estatus sistematico y Ia sinonimia de cada especie representada en Ia colecci6n. Abstract. An annotated list of non-mammalian cynodont materials in the Vertebrate Paleontology Collection of the Instituto Miguel Lillo (PVL), Universidad Nacional de Tucuman, is presented. This is the most important collection of South American Triassic tetrapods. The list is arranged at the familial level, with information on global geographic distribution and systematics. In addition, information about taxonomic status and synonymy is provided for each species represented in the collection. Key words. Cynodonts. Triassic. Vertebrate Paleontology Collection, Instituto Miguel Lillo. Palabras clave. Cinodontes. Triasico. Colecci6n de Paleontologia de Vertebrados, Institute Miguel Lillo. Introduction The Vertebrate Paleontology Collection of the Instituto Miguel Lillo, Universidad Nacional de Tucuman, is the most important collection of continental Triassic tetrapods of Argentina, and probably of South America. The fieldtrip made by Osvaldo Reig and colleagues in 1958 to the Ischigualasto Valley (Ischigualasto-Villa Union Basin) in the San Juan Province (figure 1), was the first performed by PVL researchers for the collection of Triassic fossils. At that time, many fossils, especially cynodonts and rhynchosaurs, were recovered. Subsequently, Jose Bonaparte enlarged the collection to its present significance in the record of continental Mesozoic vertebrates. During the 1960s and part of the 1970s, Bonaparte made many collecting fieldtrips to the Ischigualasto valley, Los Chafiares outcrops in La Rioja, the localities of Puesto Viejo, Agua de los Burros, and Potrerillos in Mendoza, and El Tranquilo in Santa Cruz (figure 1). Besides the fieldwork, he made important studies of the new materials (e.g. Bonaparte, 1962, 1963a, 1963b, 1963c, 1969a, 1969b, 1980; 1982 among others) and published a synthesis of his work in 'PIDBA. Catedra de Vertebrados, Facultad de Ciencias Naturales, Universidad Nacional de Tucuman. Present address: Laborat6rio de Paleontologia, Museu de Ciencias e Tecnologia, Pontificia Universidade Cat61ica do Rio Grande do Sui, Av. Ipiranga 6681, Porto Alegre, Brasil. Asociaci6n Paleontol6gica Argentina Among South American Triassic tetrapods, cynodonts and dinosaurs are the groups that called the most attention to the scientific world. One important reason was that the former documents the rise of mammals. South American cynodonts were proposed as probable mammal common ancestors (e.g. Romer, 1969c, 1970; Bonapart!? and Barberena, 1975; Crompton and Jenkins, 1979) and, more recently, they have become important in phylogenetic hypotheses about relationships of advanced cynodonts and basal mammals (e.g. Kemp, 1982, 1983; Sues, 1985; Hopson and Barghusen, 1986; Hopson, 1991, 1994; Battail, 1991; Rowe, 1986, 1988, 1993; Wible, 1991; Luo, 1994; Abdala, 1995, 1996b; Martinez et al., 1996). The PVL collection contains a remarkable number of non-mammalian cynodonts, many of them type specimens (e.g. Bonaparte, 1969a, 1969b, 1972, 1980) or well preserved specimens; some of them were especially prepared for paleoneurologic studies (Quiroga, 1979a, 1979b; 1980a, 1980b, 1980c, 1980d). Because of the relevance of this collection, it is considered important to publish this catalogue. Methods Figure 2 depicts a hypothesis of phylogenetic relationships among advanced cynodonts (= eucynodonts). In bold are the cynodont families represented in the PVL collection. The list is arranged at the fa- AMGHB / 00$

2 464 F. Abdala PP km Figure 1. Map showing Argentinian cynodont localities I Mapa de Ioca/idades argentinas con cinodontes. 1. Los Chaflares; 2. Ischigualasto; 3. Rio Mendoza; 4. Puesto Viejo. rnilial level. Information on the family distribution around the world is included and, when appropriate, comments on the systematics are made. For each species, synonyms are listed and information on the outcrop distribution and age of the stratigraphic units in which they were discovered are given. The complete list of the cynodont materials in the PVL collection is presented in an appendix, where holotypes, specimens quoted in papers, and well preserved unpublished specimens are noted. Martin Vince, technician of the Fundaci6n Miguel Lillo between 1960 and 1985, prepared most of the Triassic material in the collection. TRAVERSOOONTIDAE Huene, Herbivorous-omnivorous cynodonts (Goni and Goin, 1988), were recorded from East Africa and South Africa (Crompton; 1955; Hopson, 1984), North America (Hopson, 1984; Sues and Olsen, 1990), India (Chatterjee, 1982), and South America, where they are particularly common (Barberena, 1974; Bonaparte, 1978). One of the most characteristic features of this group is the buccolingually expanded poscanine teeth, the uppers having a rectangular outline and the lowers a quadrangular outline (figure 3). The monophyly of the Family Traversodontidae is under discussion. Traversodontidae was proposed to include tritylodontids as a late subgroup (Sues, 1985; Hopson and Barghusen, 1986), thus becoming paraphyletic (Hopson, 1991). Rowe (1986, 1993) proposed pectinate cladograms, in which gomphodont and traversodontid cynodont genera conform a series of paraphyletic taxa. In Argentina the family is recorded rather continuously from the Early to the Late Triassic (Bonaparte, 1982). Traversodontid species represented in the PVL collection are considered below. Exaeretodon frenguellii Cabrera, 1943 Figures 4.A-C 1943 Exaeretodon argentinus (Cabrera) 1963c Proexaeretodon vincei Bonaparte Specimens were collected in different levels of the Ischigualasto Formation, mostly from the Hoyada de Ischigualasto, in the Ischigualasto-Villa Union basin (figure 1). However, there are also specimens from Hoyada de Las Catas, next to Los Palacios (Bonaparte, 1966a) and from the Paso de Lamas, both in La Rioja Province. The age of the Ischigualasto Formation is early Late Triassic (Carnian) (Bonaparte, 1982; Rogers et al., 1993). Cabrera (1943), who first described cynodonts from Argentina, erected Exaeretodon frenguellii. Bonaparte (1962, 1963a, 1966a) provided detailed descriptions of the skull, postcranium and endocranial casts. Exaeretodon argentinus (Cabrera) and Proexaeretodon vincei Bonaparte are considered synonyms of E. frenguellii herein, following Hopson and Kitching (1972) and Hopson (1984: 199). The name E. frenguellii Cabrera is considered valid over E. argentinus (contra Hopson, 1984), because it was applied to the first species of Exaeretodon proposed by Cabrera. In addition, in the first revision of the genus, Bonaparte (1962: 146) explicitly proposed E. frenguellii as type species. Goni and Goin (1990) presented a description of the dental morphology and an analysis of the masticatory biomechanics of this species. Comments. The PVL collection contains more material than that presented here. Almost all the material numbered from PVL 1840 to PVL 1900 corresponds to Exaeretodon frenguellii. Materials not included in the list are fragmentary elements (particularly teeth) or badly preserved skulls and mandibles with different degrees of completeness. Ischignathus sudamericanus Bonaparte Figures S.A-B Specimens were collected in the locality of Hoyada de Ischigualasto. The holotype comes from the lower part of the Ischigualasto Formation (Bonaparte, 1963b). The species was described by Bonaparte (1963b), who listed numerous differential

3 ,(:' Catalogue of cynodonts in the Instituto Lillo collection 465,,, 6 ~fll, b-it} :.,'8, ~'8 0(:0,(:' ~'8 ~?Ji 'I:J' # 0(:0 ~0 # ~(:' ~'8 ~~ ~ :.,'8, ~' ~, i ~? -~ 'If ~ ~(:' <$-It} C)~ ~~.# <t.. c; ~#> ~" Probalnognathia Figure 2. Cladogram depicting the relationships among eucynodonts. In bold type are the cynodont families represented in the PVL collection. Relationships sensu Abdala (1996b, 1998) I Cladograma mostrando relaciones entre ellcljnodontes. Las fnnzilias de cinodontes en letras gruesas esttin representadas en Ia co/ecci6n PVL. Hip6tesis filogenetica, sensu Abdala (1996b, 1998). features with respect to Exaeretodon (but see Hopson and Kitching, 1972 and Hopson, 1984). Massetognathus pascuali Romer, 1967 Figures 6.A-C and 7.A 1967 Massetognatlws teruggii Romer; 1972 Mnssetognat/ws major Romer 1972 Megagonzphodon oligodens Romer. Specimens are from the Los Chafl.ares locality in La Rioja Province, also included in the Ischigualasto Villa Union basin. The Chafl.ares Formation is considered Middle Triassic in age (probably Ladinian, Cox, 1968; Rogers et al., 1994). Romer (1967, 1972) diagnosed two genera and four species based on material from the same locality, but only Massetognathus pascuali is considered valid herein. The reduction of the number of traversodontid species represented in the Chafl.ares Formation was already suggested by Hopson (in Bonaparte, 1982), Battail (1991) and lastly Abdala (1999a) and Abdala and Giannini (2000). Quiroga (1979a, 1980b, 1980d) made paleoneurologic studies on endocranial casts. Comments. Many specimens are well preserved in partially prepared concretions. This species is highly dominant in the Los Chafl.ares fauna, comprising nearly 56% of the recorded tetrapods (Arcucci et al., 1994). Andescynodon mendozensis Bonaparte, 1969 Figures 8.A-B Specimens are from the Rio Mendoza Formation (Bonaparte, 1969b) in Cerro Bayo at Potrerillos, Mendoza Province. Bonaparte (1982) and King (1993) considered the Rio Mendoza Formation as synchronic with the P.uesto Viejo Formation, and upper Scythian in age. However, the Rio Mendoza Formation has been considered also as Late Anisian (Anderson and Anderson, 1993) and Ladinian (Stipanicic, 1983; Baez et al., 1993). The species was described by Bonaparte (1969b, figure l.a). Quiroga (1980b) made paleoneurologic studies and Gofii (1986), and Gofu and Goin (1988) studied the cranial morphology, tooth succession, and masticatory biomechanics. Comments. Juveniles of Andescynodon mendozensis possess sectorial posterior postcanines that are replaced by gomphodon teeth in adults (Gofu, 1986; Goni and Goin, 1988). Postcranial elements and mandibles not associated with skull remains are included in Andescynodon with doubt owing to the remarkable similarity of this species to Rusconiodon mignonei (see below). There are concretions with well-preserved remains of the vertebral column and appendicular skeleton. Rusconiodon mignonei Bonaparte, 1970 Figure 8.C Specimens are from the same locality as Andescynodon mendozensis. The species was erected by Bonaparte (1970) and redescribed by Gofii and

4 F. Abdala Andescynodon. Cynognathus Assemblage Zone and an Anisian age for the uppermost part, based on the amphibian fauna (Hancox et al., 1995) and the presence of the dicynodont Angonisaurus (Hancox and Rubidge, 1996). Pascualgnathus polanskii was described by Bonaparte (1966c) and is considered a primitive traversodontid (Bonaparte, 1966c; Barberena, 1974; Hopson, 1991). Comments. PVL 4416, the best preserved specimen, was discovered after the original description was published (probably in 1970). Massetognathus Exaeretodon Figure 3. Upper (left column) and lower (right colum) postcanines of traversodontid cynodonts I Postcaninos superiores (columna izquierda) e inferiores (columna derecha) de cinodontes traversod6ntidos. Andescynodon (from Goi'ii and Goin, 1988), Massetognathus (modified from Romer, 1967) and Exaeretodon (from Crompton, 1972). Abdala (1988). Rusconiodon mignonei is similar to A. mendozensis in many features (e.g., the dentition, and general size of the skull) but possesses a paracanine fossa that perforates the muzzle dorso-labially (Bonaparte, 1970; Gofii and Abdala, 1988). Comments. Almost all the material (except PVL 3892d) was studied by Gofii and Abdala (1988). Specimen PVL 3900 has a skull noticeably larger than the rest of the specimens. Pascualgnathus polanskii Bonaparte, 1966 Figures 9.A-B Specimens are from the locality of Puesto Viejo, west of Colonia Las Malvinas, nearly 30 km from the city of San Rafael, Mendoza Province (Puesto Viejo Formation). Most authors consider this formation as Upper Scythian (e.g. Bonaparte, 1982; Battail, 1988; King, 1993; Anderson and Anderson, 1993). However, Stipanicic (1983), and Shubin and Sues (1991) interpreted the Cynognathus Assemblage Zone deposits of South Africa, equivalent to this section of the Puesto Viejo Formation, as lower Middle Triassic (Anisian). More recently, Hancox and Rubidge (1996) proposed a Scythian age for the lower part of the B Scm 4cm Figure 4. A, right lateral view of the skull of Exaeretodon frenguellii Cabrera (PVL 2473) I vista lateral derecha del cnineo de Exaeretodon frenguellii Cabrera (PLV 2473). B, lateral view of the mandible of E. frengnellii (PVL 2467) I vista lateral de Ia nrandfbula de E. frenguellii (PLV 2467). C, right lateral view of the skull and lower jaws of E. frenguellii (from Hopson, 1984) I vista lateral derecha del crtineo y mandfbula de E. frenguellii (de Hopson, 1984).

5 Catalogue of cynodonts in the Instituto Lillo collection 467 Figure 5. A, ventral view of the skull of Ischignathus sudamericanus Bonaparte (modified from Bonaparte, 1963b) I vista ventral del craneo de Ischignathus sudamericanus (modificado de Bonaparte, 1963b) B, medial view of the lower jaw of I. sud american us (modified from Bonaparte, 1963b) I vista medial de Ia mandibula de I. sudamericanus (nrodificado de Bonaparte, 1963b) CYNOGNATHIDAE Watson, 1917 This group is especially well recorded in South Africa, where it is one of the most common components of the Cynognathus Assemblage Zone (Kitching, 1977). It was also recorded in Antarctica, where it is represented by mandibular fragments (Hammer, 1995). Cynognathus crateronotus Seeley, 1895 Figures 10.A-D 1969 Cynognathus minor Bonaparte The only known Argentinian specimen was collected from the same levels as Pascualgnathus polanskii (Bonaparte, 1978, see above). It was discovered in 1966 by Bonaparte, who described it as Cynognathus minor (Bonaparte, 1969a). Abdala (1996a, 1999b) published a redescription of the skull and associated postcranial remains. This species is considered a junior synonym of C. crateronotus of South Africa (Hopson and Kitching, 1972; Abdala, 1996a). PROBAINOGNATHIDAE Romer, 1973 Monotypic family represented only in Los Chaftares locality, Middle Triassic, La Rioja Province (Romer, 1970). Probainognathus jenseni Romer, 1970 Figures 1l.A-D When Romer (1969c, 1970) described this species, he included it in Chiniquodontidae, but later Romer (1973) proposed the new family Probainognathidae for the new taxon. The inclusion of this species in Chiniquodontidae was accepted recently by Battail (1991), whereas its inclusion in Probainognathidae was supported by Hopson and Barghusen (1986), Hopson (1991), and Abdala (1996b). Probainognathus jenseni was postulated as the common ancestor of mammals in the 1970s (Romer, 1969c, 1970; Crompton and Jenkins, 1979). Quiroga (1980a, 1980c) made paleoneurologic studies on an endocranial cast. Comments. These materials were examined by Abdala (1996b) in his revision of the South American chiniquodontoids. Because the holotype was stolen from the collection of the Universidad Nacional de La Rioja, Abdala (1996b) designated the specimen PVL 4677 as the neotype. The species represents nearly 15% of the Los Chaftares vertebrate fauna (Arcucci et al., 1994; Rogers et al., 1994; Abdala, 1996b). The specimens PVL 4445, PVL 4446 and PVL 4447 consist of mandibular rami of juveniles with well-preserved crowns, providing information on the original structure of the postcanines in the group. CHINIQUODONTIDAE Huene, Medium-sized carnivorous cynodonts, with sec- A 2cm c 2cm Figure 6. A-B, dorsal and palatal views of a juvenile of Massetognathus paswali Romer (PVL 4613) I vistas dorsal y palatal de un ejemplar juvenil de Massetognathus pascuali Romer (PVL 4613). C, lateral view of the skull and lower jaw of M. pascuali (modified from Romer, 1967) I vista lateral del craneo y mandibula de M. pascuali (modificado de Romer, 1967).

6 468 F. Abdala A 1 em B 1 em Figure 7. A, dorsal view of the endocranial cast of Massetognathus pascuali Romer (PVL 4016; modified from Quiroga, 1979a) I vista dorsal del molde endocraniano de Massetognathus pascuali (PLV 3016); modificado por Quiroga, 1979a) B, dorsal view of the endocranial cast of Chiniquodon theotonicus Huene (PVL 4015; modified from Quiroga, 1979a). Arrow indicates semicircular canals from the inner ear I vista dorsal del mol de endocraniano de Chiniquodon theotonicus (PL V 4015; modificado por Quiroga, 1979a). La fleclm indica los canales semicirculares del oido interno. torial postcanines having the principal cusp backwardly curved (figure 12). Firstly, they were considered a South American group, with representatives in Brazil (Huene, ; Romer, 1969a; Teixeira, 1982) and Argentina (Bonaparte, 1966b; Romer, 1969b; 1970, 1973). Subsequently, Aleodon brachyramphus of the Middle Triassic of Tanzania (Hopson and Kitching, 1972; Hopson and Barghusen, 1986), Cromptodon mamiferoides of the Lower Triassic of Argentina (Hopson, 1991; Battail, 1991, see below), Cistecynodon parvus of the Lower Triassic of South Africa, and Thrinaxodon brasiliensis of the Middle Triassic of Brazil (Battail, 1991) were included in the family. Abdala (1996b) made a revision of the Chiniquodontidae; based on his family diagnosis, the group is considered to include only South American forms. Chiniquodon theotonicus Huene ( ) Figures 7.B and 12.A-D 1969 Probelesodon lewisi Romer 1973 Probelesodon minor Romer Chiniquodon theotonicus was erected by Huene ( ) based on fragmentary material from the Santa Maria Formation in southern Brazil. Abdala (1996b) synonymized Probelesodon lewisi and P. minor (both from the Chanares Formation, Argentina; Romer, 1969b, 1973) with C. theotonicus. Quiroga (1979a, 1979b, 1980c, 1980d) made paleoneurologic studies and described the inner ear based on endocraneal casts. Comments. The first three specimens listed in the Appendix were found in the Ischigualasto Formation, at the Hoyada de Ischigualasto in San Juan (Bonaparte, 1966b), and the remaining material was found in the Chanares Formation in La Rioja. Material of this species was studied by Abdala.> A 2cm c Figure 8. A, palatal view of Andescynodon mendozensis Bonaparte (holotype, modified from Bonaparte, 1969b) I vista dorsal del holotipo de Andescynodon mendozensis (modificado de Bonaparte, 1969b). B, medial view of the lower postcanines of a juvenile of A. mendozensis (PVL 4390; from Gofu and Goin, 1988) I vista medial de los postcaninos inferiores de un juvenil de A. mendozensis (PLV 4390; de Gofii y Go in, 1988). C, detail of the paracanine fossae in Rusconiodon mignonei Bonaparte (from Gofu and Abdala, 1988) I detalles de las fosas paracaninas en R. mignonei (de Gofii y Abdala, 1988).

7 Catalogue of cynodonts in the Institute Lillo collection 469 2cm A - known by the upper postcanines, they are remarkably different in their morphology from those of Pachygenelus and Diarthrognathus. Some authors (e.g. Kemp, 1983) considered all the described specimens to be juveniles. Chaliminia musteloides Bonaparte, 1978 Figures 13.A-B Small cynodont with a skull about 48 mm long. The holotype came from the western border of the Cerro Rajado, La Rioja. It was collected in the upper section of the Los Colorados Formation (Bonaparte, 1980), considered Norian (Bonaparte, 1982; Rougier et al., 1995). 5an 8 Figure 9. A, dorsal view of Pascualgnatlms polanskii Bonaparte (PVL 4416) I vista dorsal de PasCIIalgnatlms polanskii (PLV 4416). B, lateral view of the skull and lower jaw of P. polanskii (from Bonaparte, 1966c) I vista lateral del craneo y mandfbula de P. polanskii (de Bonaparte, 1966c). (1996b) in his revision of the South American chiniquodontoids. Chiniquodon represents nearly 10 % of the vertebrates of Los Chanares fauna (Abdala, 1996b; Arcucci et al., 1994). TRITHELEDONTIDAE Broom, 1912 Small sized cynodonts, known from South Africa (Broom, 1932; Gow, 1980), South America (Bonaparte, 1980) and North America (Shubin et al., 1991). At first considered as a distinctive infraorder, Ictidosauria, (Broom, 1932), Hopson and Kitching (1972) proposed the name Tritheledontidae and included them within Cynodontia. Bonaparte (1980) recognized two families of ictidosaurs: Tritheledontidae, with upper and lower postcanines transversely enlarged, including Tritheledon and Diarthrognathus, and Pachygenelidae, with lower postcanines laterally compressed and upper postcanines less laterally compressed, which includes Pachygenelus and Chaliminia. Gow (1980) made a detailed description of the dentition of the South African representatives, concluding that the post canines of Diarthrognathus are readily derivable from those of Pachygenelus, while in Tritheledon, only c Figure 10. A-B, dorsal and lateral views of Cynognathus crateronotus Seeley (PVL 3859, modified from Abdala, 1996a) I vistas dorsal y lateral de Cynognathus crateronotus (PLV 3859, modificado de Abdala, 1996a). C, anterior view of a dorsal vertebra of C. crateronotus (from Abdala, 1999b) I vista posterior de una vertebra dorsal de C. crateronotus (de Abdala, 1999b). D, right humerus of C. crateronotusin dorsal view (from Abdala, 1999b) I lrumero dereclro en vista dorsal de C. crateronotus (de Abdala, 1999b).

8 0., F. Abdala A 2cm B A 2cm B c ~,,~"lf'~ -.. ~ c C!J? 4ITI'll D 5mm Figure 11. A-8, dorsal and palatal views of the skull of Probainognatlms jenseni Romer (modified from Romer, 1970). C, upper and lower teeth series of an aged specimen of P. jenseni in lateral view (PVL 4678). Note the conspicuous worn-out condition of the postcanines. D, lateral view of a juvenile lower jaw of P. jenseni I A-B, vistas dorsal y palatal del craneo de Probainognatlms jenseni ( modificado de Romer, 1970). C, dientes superiores e inferiores de 1m ejemplar adulto de P. jenseni (PVL 4678) en vista lateral. Observe e/ notable desgaste de los poscaninos. D, vista lateral de Ia mandfbula de un juvenil de P. jenseni. TruTYLODONTIDAE Cope 1884 This group represents the last survivors of nonmammalian cynodonts. They were herbivorous rodent-like forms that lived from the Late Triassic to the Middle or Late Jurassic in southern Africa, China, Great Britain, Germany, the United States, Mexico and South America (Clark and Hopson, 1985). cf. Tritylodon The assignment of the material to Tritylodontidae sh ould be considered with caution because this taxon is represented solely by postcranial fragments. These remains were collected in the upper part of the Los Colorados Formation; they occur with ornithosuchian and crocodilian remains (Bonaparte, 1971). INCERTAE SEDIS Cromptodon mamiferoides Bonaparte, 1972 Figures 14.A-B Figure 12. A-8, dorsal and pala tal views of the skull of Clliniquodon tlleotonicus Huene (PVL4674; from Abdala, 1996b). C, upper right postcanine series of C. tlleotonicus (PVL 4444) in labial and occlusal views. D, lower left postcanine series of C. tlleotonicus (PVL 4444) in labial and occlusal views I A-B, vistas dorsal y palatal del craneo de Clliniquodon theotonicus Huene (PVL 4674; tornado de Abdala, 1996b). C, serie poscanina derecha superior de C theotoniciis (PVL 4474) en vistas labial y oc/usa/. D, serie poscanina izquierda inferior de C. theotonicus (PVL 4444) en vistas labial y oc/usa/. Small species with an estimated skull length of about 2.7 em, solely represented by a mandible. It comes from the middle section of the Rio Mendoza A 5mm 8 Figure 13. A, right lateral view of Cllaliminia musteloides Bonaparte (modified from Bonaparte, 1980). B, upper and lower postcanines of C. musteloides in lateral view (from Bonaparte, 1980) I A, vista lateral derecha de Cllaliminia musteloides Bonaparte (modificado de Bonaparte, 1980). B, poscaninos superiores en inferiores de C. musteloides en vista lateral (tonrado de Bonaparte, 1980).

9 Catalogue of cynodonts in the Instituto Lillo collection 471 Lin PostJ A 5mm B 1mm Figure 14. ~~lateral view of the mandible of Cromptodon mamiferoides Bonaparte (PVL 3858-holotype). B, labial and occlusal views of the _rostcanmes 4 and 5 of C. mamiferoides ~mod if.ied from Bonaparte, 1972) I A, vista lateral de Ia mandibula de Cromptodon mamiferoides Bonaparte (PVL 3858-holotlpo). B, VIsta /abml y oclusal de los poscaninos 4 y 5 de C. mamiferoides (modificado de Bonaparte, 1972). Formation, northern slope of the Cerro Bayo of Abdala, F An approach to the phylogeny of gomphodont Potrerillos, Mendoza Province (Bonaparte, 1978). The cynodonts based on dental characters. Journal of African Earth d Sciences 27: 1-2. b spec1es B was consi ered a galesaurid when described Abdala, F. 1999a. Algunos aspectos acerca de Ia ontogenia de Y onaparte (1972). Lately, Hopson (1991) and Massetognatl!us pascua/i (Cynodontia-Traversodontidae) de Battail (1991) placed it in Chiniquodontidae. Hopson Los Chanares, Triasico Media, Argentina. Ameghiniana 36: 95. (1991) pointed out that the teeth of this species are Abdala, F. 1999b. Elementos postcraneanos de Cynognatl!us del similar to those of juveniles of Aleodon from Africa, a Triasico Inferior de Ia provincia de Mendoza, Argentina. Consideraciones sabre Ia morfologia del humero en cingenus included in Chiniquodontidae by these au- odontes. Revista Espanola de Paleontologfa 14: thors. Abdala (1996b) recognized some similarity be- Abdala, F. and Giannini, N.P Gomphodont cynodonts of the tween the dentition of Cromptodon and Aleodon; this Chaf\ares Formation: the analysis of an ontogenetic sequence. supports inclusion of both genera in the same group. Journal of Vertebrate Paleontolog~; 20: Anderson, J.M. and Anderson, H.M Terrestrial flora and tau- However, the tooth morphology of these forms, in na of the Gondwana Triassic: Part 1- Occurrences. In: S.G. Lucas which the cingulum is present, is different from that and M. Morales (eds.), The Nonmarine Triassic, New Mexico considered diagnostic of Chiniquodontidae b y Museum of Natural History and Science Bulletin 3: Abdala (1996b). This species is considered here as in- Arcucci, A.B., Abdala, F., Rogers, R.R. and Sereno, P.C Tafonomia de Ia Formaci6n Chaftares (Triasico Media), certae sedis. Gofi.i and Goin (1987) studied this mater- provincia de La Rioja, Argentina. 6 Congreso Argentino de ial to interpret the probable origin of the gom- Paleontologfa y Bioestratrigrajfa (Trelew, 1994) Resumenes: 17. phodont postcanines in traversodontids. Baez, A.M., Marsicano, C.A. and Cione, A.L Vertebrados Mesozoicos. In: V.A. Ramos (ed.), Relatorio del 2 Congreso Geologico Argentino y 2 Congreso de Explotacion de Aknowledgments Hidrocarburos (Mendoza), Geologia y Recursos Naturales de Mendoza 2: Barberena, M.C Contribui<;ao ao conhecimento dos cynodontes gonfodontes (Cynodontia-Tritylodontoidea) do Brasil. I am indebted to J. Powell of the Universidad Nacional de Tucuman for the opportunity to study the cynodonts of the Vertebrate Paleontology Collection in the lnstituto Miguel Lillo. A. Ministerio de educa~iio e cultura, Universidade Federal do Rio Grande do Sui, 194 p. Arcucci, J. F. Bonaparte, A. Cruickshank, G. Esteban, C. Gow, R. Battail, B Biostratigraphie des formations permo-triasiques Herbst, S. Modesto and A. Scanferla made useful comments and continentales a Vertebres tetrapodes et biogeographie du suggestions that greatly improved the manuscript. Comments and Gondwana. Anna/es de Ia Societe Geologique du Nord 57: advice by B. Battail and G. Rougier are also recognized. P. Battail, B Les Cynodontes (Reptilia, Therapsida): une phylogenie. Bulletin Museum national Histoire naturelle, Paris, 4e Theobald and M. Griffin helped with the English version. The Consejo Nacional de Investigaciones Cientificas y Tecnicas, the ser., 13, section C, 1-2: CNPq (Conselho Nacional de Desenvolvimento Cientifico e Bonaparte, J.F Descripci6n del craneo y mandibulas de Tecnol6gico, Brazil, and the MCT-Pontificia Universidade Catolica Exaeretodon frmguellii Cabrera, y su comparaci6n con do Rio Grande do Sui) made possible this contribution by financial Diademodontidae, Tritylodontidae y los cinodontes support. sudamericanos. Pub/icaciones del Museo Municipal de Ciencias Naturales y Tradicionales de Mar del Plata 1: Bonaparte, J.F. 1963a. Descripci6n del esqueleto postcraneano de References Exaeretodon (Cynodontia-Traversodontidae). Acta Geologica Abdala, F The Family Chiniquodontidae and its relationships Lil/oana 4: Bonaparte, J.F. 1963b. Descripci6n de among eucynodonts. Journal of Vertebrate Paleontology lschignatl!us sudamericanus n. 15: 16A. Abdala, F. 1996a. Redescripci6n del craneo y reconsideraci6n de Ia gen., n. sp., nuevo cinodonte gonfodonte del Triasico media superior de San Juan, Argentina. validez de Cynognathus minor Acta Geologica Lilloana 4: (Eucynodontia-Cynognathidae) Bonaparte, J.F. 1963c. Un nuevo cinodonte gonfodonte del Triasico del Triasico Inferior de Mendoza. Ameghiniana 33: media Superior de San Juan, Abdala, F. 1996b. [Los cl!iniquodontoideos (Synapsida, Cynodontia) Proexaeretodon vincei n. gen., n. sp. (Cynodontia-Traversodontidae). sudamericanos. Acta Geologica Lilloana 4: Tesis Doctoral, Universidad Nacional de Tucuman. 381 pp. Inedito]

10 472 F. Abdala Bonaparte, J.F. 1966a. Sobre las cavidades cerebral, nasal y otras estructuras del craneo de Exaeretodon sp. (Cynodontia Traversodontidae). Acta Geologica Lilloana 8: Bonaparte, J.F. 1966b. Chiniquodon Huene (Therapsida Cynodontia) en el Triasico de Ischigualasto, Argentina. Acta Geologica Lil/oana 8: Bonaparte, J.F. 1966c. Una nueva "fauna" triasica de Argentina (Therapsida: Cynodontia, Dicynodontia). Consideraciones filogeneticas y paleobiogeograficas. Ameghiniana 4: Bonaparte, J.F. 1969a. Cynognathus minor n. sp. (Therapsida Cynodontia). Nueva evidencia de vinculaci6n faunistica afrosudamericana a principios del Triasico. 1 Coloquio Gondwana Stratigraphy, I.U.G.S (Mar del Plata 1967), pp Bonaparte, J.F. 1969b. Dos nuevas "faunas" de reptiles triasicos de Argentina. 1 o Coloquio Gondwana Stratigraphy, I.U.G.S (Mar del Plata 1967), pp Bonaparte, J.F Annotated list of the South American Triassic tetrapods. 2 Gondwana Symposium, Proceedings and Papers, pp Bonaparte, J.F Los tetrapodos del sector superior de Ia Formaci6n Los Colorados, La Rioja, Argentina (Triasico Superior). I parte. Opera Lil/oana 23, 183 p. Bonaparte, J.F Cromptodon mamiferoides, Galesauridae de Ia Formaci6n Rio Mendoza, Mendoza, Argentina (Therapsida Cynodontia). Ameghiniana 9: Bonaparte, J.F El Mesozoico de America del Sur y sus tetrapodos. Opera Lil/oana 26, 596 p. Bonaparte, J.F El primer ictidosaurio (Reptilia-Therapsida) de America del Sur, Chaliminia musteloides, del Triasico Superior de La Rioja, Republica Argentina. 2 Congreso Argentino de Paleontologfa y Bioestratigrafia y 1 o Congreso Latinoamericano de Paleontologfa (Buenos Aires 1978), Aetas 1: Bonaparte, J.F Faunal replacement in the Triassic of South America. Journal of Vertebrate PaleontologJJ 2: Bonaparte, J.F. and Barberena, M.C A possible mammalian ancestor from the Middle Triassic of Brazil (Therapsida Cynodontia). Journal of PaleontologJJ 49: Broom, R The mammal-like reptiles of South Africa and the origin of mammals. H.F. and G. Witherby (eds.), London, 376 p. Cabrera, A El primer hallazgo de terapsidos en Ia Argentina. Notas del Museo de La Plata, Paleontologia 55: Chatterjee, S A new cynodont reptile from the Triassic of India. Journal of PaleontologJJ 56: Clark, J.M. and Hopson, J.A Distinctive mammal-like reptile from Mexico and its bearing on the phylogeny of the tritylodontidae. Nature 315: Cox, C.B The Chafiares (Argentina) Triassic reptile fauna. IV. The Dicynodonts fauna. Breviora 295: Crompton A.W On some Triassic cynodonts from Tanganyika. Procedings of the Zoological Society of London 125: Crompton, A.W Postcanine occlusion in cynodonts and tritylodontids. Bulletin British Museum Natural Histon;, GeolOgJJ 21: Crompton A.W. and Jenkins, F.A. Jr Origin of mammals. In: J. Lillegraven, Z. Kielan-Jaworowska and W. Clemens (eds.), Mesozoic mammals: the first two thirds of mammalian histon;, University of California Press, Berkeley, pp Goii.i, R.G Reemplazo de dientes postcaninos en Andescynodon mendozensis, Bonaparte (Cynodontia Traversodontidae). 4 Congreso Argentino de Paleontologia y Bioestratigrafia (Mendoza), Aetas 2: Goii.i, R.G. and Abdala, F Consideraciones sobre Ia morfologia craneo-dentaria de Rusconiodon mignonei (Cynodontia Traversodontidae): diagnosis, afinidades y variaciones ontogeneticas. Ameghiniana 25: Goii.i, R.G. and Goin, F.J El origen de los postcaninos gonfodontes de Andescynodon mendozensis Bonaparte (Cynodontia, Traversodontidae). Ameghiniana 24: Goii.i, R.G. and Goin, F.J Morfologia dentaria y biomecanica masticatoria de los cinodontes (Reptilia-Therapsida) del Triasico argentino. I. Andesetjnodon mendozensis Bonaparte (Traversodontidae). Ameghiniana 25: Goii.i, R.G. and Goin, F.J Morfologia dentaria y biomecanica masticatoria de los cinodontes (Reptilia-Therapsida) del Triasico argentino. II-Exaeretodon frengue/lii Cabrera (Traversodontidae). Ameghiniana 27: Gow, C.E The dentitions of the Tritheledontidae (Therapsida: Cynodontia). Proceedings of the Royal Society of London (B) 208: Hammer, W.R New therapsids from the upper Fremouw Formation (Triassic) of Antarctica. Journal of Vertebrate PaleontologJJ 15: Hancox, P.J. and Rubidge, B.S The first specimen of the Mid-Triassic dicynodont Angonisaurus from the Karoo of South Africa: implications for the dating and biostratigraphy of the Cynognathus Assemblage Zone, Upper Beaufort Group. South African Journal of Science 92: Hancox, P.J., Shishkin, M.A., Rubidge, B.S. and Kitching, J.W A threefold subdivision of the Cynognathus Assemblage Zone (Beaufort Group, South Africa) and its paleogeographical implications. South African Journal of Science 91: Hopson, J.A Late Triassic traversodont cynodonts from Nova Scotia and Southern Africa. Palaeontologia Africana 25: Hopson, J. A Systematics of the Nonmammalian Synapsida and Implications for Patterns of Evolution in Synapsida. In: H.-D. Schultze and L. Trueb (eds.), Origin of the higher groups of tetrapods, Controversy and Consensus, Comstock Publishing Associates, Cornell University Press, pp Hopson, J.A Synapsid evolution and the radiation of noneutherian mammals. In: R.S. Spencer (ed.), Major Features of Vertebrate Evolution, The University of Tennessee, Knoxville Publication, pp Hopson, J.A. and Barghusen, HR An analysis of therapsid relationships. In: N. Hatton lll, P. MacLean, J. Roth and E. Roth (eds.), The ecology and biologjj of mammal-like reptiles, Smithsonian Institution Press, pp Hopson, J.A. and Kitching, J.W A revised classification of cynodonts (Reptilia-Therapsida). Palaeontologia Africana 14: Huene, F. von Die fossilen Reptilien des Sudamerikanischen Gondwana/andes. 2. Lieferung, Cynodontia. F. Heine, Tubingen, pp Kemp, T.S Mammal-like Reptiles and the Origin of Mammals. Academic Press, London, 363 p. Kemp, T.S The relationships of mammals. Zoological Journal of the Linnean Society 77: King, G.M Ecology and biogeography of Triassic non-mammalian therapsids. In: J.M. Mazin and G. Pinna (eds.), Evolution, ecology and biogeography of the Triassic reptiles. Paleontologia Lombarda della Societa Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano, Nuova Serie 2: Kitching, J.W The distribution of the Karroo vertebrate fauna. Bernard Price Institute for Palaeontological Research, Memoir 1: Luo, z Sister-group relationships of mammals and transformation of diagnostic mammalian characters. In: N.C. Fraser and H.-D. Sues (eds.), In the shadow of the dinosaurs: early Mesozoic tetrapods, Cambridge University Press, pp Martinez, R.N., May, C.L. and Forster, C.A A new carnivorous cynodont from Ischigualasto Formation (Late Triassic, Argentina), with comments on eucynodont phylogeny. Journal of Vertebrate PaleontologJJ 16: Quiroga, J.C. 1979a. The brain of two mammal-like reptiles (Cynodontia-Therapsida). Journal for Hirnforsclnmg 20: Quiroga, J.C. 1979b. The inner ear of two cynodonts (Reptilia-

11 Catalogue of cynodonts in the Instituto Lillo collection 473 L Therapsida) and some comments on the evolution of the inner ear from pelycosaurs to mammals. Gegenbaurs morplzologisclzes Jalzrbuclz125: Quiroga, J.C. 1980a. The brain of the mammal-like reptile Probainognathus jenseni (Therapsida-Cynodontia). A correlative paleo-neoneurological approach to the neocortex at the reptile-mammal transition. Journal fiir Hirnforsc/zung 21: Quiroga, J.C. 1980b. Further studies on cynodont endocasts (Reptilia-Therapsida). Zeitsc/zrift fur mikroskopisclz-anatomisc/ze Forsc/wng 94: Quiroga, J.C. 1980c. Sobre un molde endocraneano del cinodonte Probainognatlzus jenseni Romer, 1970 (Reptilia, Therapsida) de Ia Formaci6n Ischichuca (Triasico Medio), La Rioja, Argentina. Ameglziniana 12: Quiroga, J.C. 1980d. Descripci6n de los moldes endocraneanos de dos cinodontes (Reptilia-Therapsida) de Los Chaftares Triasico Medic- de Ia provincia de La Rioja (Argentina). Notas sobre el sistema vascular intracraneano y relaciones con los mol des de otros cinodontes en funci6n de Ia morfologia de los mas antiguos moldes mamalianos conocidos. 2 Congreso Argentino de Paleontologfa y Bioestratigrafia y 1 Congreso Latinoamericano de Paleontologfa (Buenos Aires 1978), Aetas 1: Rogers, R.R., Swisher ill, C. C., Sereno, P.C. Monetta, A.M., Forster, C.A. and Martinez, R.N The Ischigualasto tetrapod assemblage (Late Triassic, Argentina and '"Ar,.Ar dating of dinosaur origins. Science 260: Rogers, R.R., Arcucci, A.B., Forster, C.A., Abdala, F. and Sereno, P.C Stratigraphic context and taphonomy of the middle Triassic Los Chafiares Fauna, La Rioja Province, Argentina. Journal of Vertebrate Paleontology 14: 43A. Romer, A.S The Chaftares (Argentina) Triassic reptile fauna. III Two new gomphodonts, Massetognat/ws pascuali and Massetognat/ws teruggii. Breviora 264: Romer, A.S. 1969a. The Brazilian cynodont reptiles Belesodon and Clziniquodon. Breviora 332: Romer, A.S. 1969b. The Chafiares (Argentina) Triassic reptile fauna. V. A new chiniquodontid cynodont, Probe/esodon lewisi. Cynodont ancestry. Breviora 333: Romer, A.S. 1969c. Cynodont reptile with incipient mammalian jaw articulation. Science 166: Romer, A.S The Chaftares (Argentina) Triassic reptile fauna. VI. A chiniquodontid cynodont with an incipient squamosaldentary jaw articulation. Breviora 344: Romer, A.S The Chaftares (Argentina) Triassic reptile fauna. XVIT. The Chaftares gomphodonts. Breviora 396: 1-9. Romer, A.S The Chana res (Argentina) Triassic reptile fauna. XVIII. Probelesodon mi11or, a new species of carnivorous cynodonts. Family Probainognathidae. Breviora 401: 1-4. Rougier, G.W., de Ia Fuente, M.S. and Arcucci, A.B Late Triassic turtles from South America. Science 268: Rowe, T [Osteofogical diagnosis of Mammalia, L. 1758, a11d its relations/zips to exti11ct Synapsida. Ph.D. Dissertation, 446 p. University of California, Berkeley. Unpublished]. Rowe, T Definition, diagnosis and origin of Mammalia. Journal of Vertebrate Paleontology 8: Rowe, T Phylogenetic Systematics and the Early History of Mammals. In: F. Szalay, M. Novacek and M. McKenna (eds.), Mammal Phylogeny. Mesozoic Differentiation, Multituberculates, Monotremes, Early Tlzerians, arzd Marsupials, Springer Verlag, pp Seeley, H.G Researches on the structure, organization, and classification of the fossil Reptilia. Pt. 9, section 5. On the skeleton in new Cynodontia from the Karroo rocks. Plzilosoplzical Transactions of tlze Royal Sociehj B 186: Shubin, N.H., Crompton, A.W., Sues, H.D. and Olsen, P.E New fossil evidence on the sister-group of mammals and early Mesozoic faunal distribution. Scie11ce 251: Shubin, N.H. and Sues, H.-D Biogeography of early Mesozoic continental tetrapods: patterns and implications. PaleobiolOgJJ 17: Stipanicic, P.N The Triassic of Argentina and Chile. In: M. Moulade and A.E.M. Nairn (eds.), The Phanerozoic Geology of the World II. Tlze Mesozoic, B. Elsevier, pp Amsterdam. Sues, H.-D The relationships of the Tritylodontidae (Synapsida). Zoological Journal Linnean Socieh; 85: Sues, H.-D. and Olsen, P.E Triassic vertebrates of Gondwanan aspect from the Richmond basin of Virginia. Science 249: Teixeira, A.S Urn novo cinodonte carnivore (Probe/esodon kitchi11gi sp. nov.) do Triassico do Rio Grande do Sui, Brasil. Comunica~oes do Museu de Ciencias da Pontificia Universidade Catolica do Rio Grande do Su124: Wible, J.R Origin of Mammalia: the craniodental evidence reexamined. Joumal of Vertebrate Paleontologtj 11: Recibido: 14 de mayo de Aceptado: 28 de abril de Appendix. List of cynodont materials in the PVL collection. TRAVERSODONTIDAE Huene Exaeretodon frettgjtellii Cabrera, 1943 PVL Distal portion of the femur. Material used in postcranial study (Bonaparte, 1963a). PVL Mandibular fragment with teeth, one of them erupting. PVL Anterior portion of both mandibular rami. Material used for study of masticatory biomechanics (Gofti and Coin, 1990). PVL Maxillary fragment with postcanines. PVL Maxillary fragment with incisors, canines, and posteanines. PVL Three postcanines. PVL Skull and mandible with a reduced diastema, showing the minimum number of postcanines (6) for the species (Bonaparte, 1962, fig. 15). PVL Incomplete skull and mandible, with endocranial cast. Material used in the description of the skull and mandible (Bonaparte, 1962), and one of the most important specimens in the endocranial study (Bonaparte, 1966a). PVL Mandible of a juvenile, lacking the anterior portion. Material used in the description of the skull and mandible (Bonaparte, 1962). PVL Large skull, with the maximum number of postcanines (11) for the species (Bonaparte, 1962). PVL Skull lacking the left zygomatic arch. PVL Skull and mandible in occlusion, with upper tooth row visible laterally. PVL Large skull. PVL Small skull, with the minimum number of postcanines (6) for the species (Bonaparte, 1962). PVL Skull with nasal and cephalic endocasts. Specimen used for endocranial study (Bonaparte, 1966a). PVL Symphyseal region of both mandibles with incisors. PVL Left mandibular ramus of large size, with two posteanines, one of them erupting. Material used in the description of the skull (Bonaparte, 1962). PVL Skull and mandible partially articulated, lacking the right zygomatic arch. Material used in the description of the skull (Bonaparte, 1962). PVL Numerous isolated postcanines with breaks at various levels of crowns and roots. PVL Complete femur, tibia, and fibula; well preserved fragments of ilium. Material used in the description of the postcranial skeleton (Bonaparte, 1963a). PVL Fragment of maxilla with well preserved postcanine and an isolated postcanine used to illustrate upper postcanine morphology (Bonaparte, 1962, figs. 10, 11 y 12; lamina ill), and al-

12 474 F. Abdala so in the masticatory biomechanics study of Goih and Goin (1990). PVL Fragment of mandible with well preserved postcanines, some of them recently erupted. PVL Well preserved lower tooth series, used to illustrate lower postcanine morphology (Bonaparte, 1962, figs. 13 y 14; lamina IV, fig. 2). PVL Small postcanine erupting. PVL Well preserved, incomplete femur. PVL Right mandibular ramus with 6 postcanines and a posterior alveolus (figure 4.B), complete humerus, distal part of humerus, complete scapular blade, procoracoids, two clavicles, interclavicles, radius, ulna, and fragment of femur. Material used in the description of the postcranial skeleton (Bonaparte, 1963a). PVL Mandible with complete dentition. Material used for study of masticatory biomechanics (Goni and Gain, 1990). PVL Left postero-lateral portion of the skull, with the posterior part of the dentary and postdentary bones articulated. Material used to show details of postdentary bones (Bonaparte, 1962, lamina IV, fig. 1). PVL Skull lacking the left zygomatic arch, showing two postcanines in each row (figure 4.A). The bones forming the cephalic cavity are laterally crushed. An important specimen both for the skull description (Bonaparte, 1962, lamina II) and for the cerebral cavity study (Bonaparte, 1966a). PVL Large mandible bearing a complete tooth row. PVL Right portion of the skull of a juvenile, with well preserved teeth, but partially covered; fragmentary mandible with postcanines; stapes; humeral distal portion. PVL Proximal fragment of the femur. Material used in the postcranial description (Bonaparte, 1963a). PVL Incomplete skull and an almost complete postcranial skeleton, well preserved. An important specimen for the postcranial description (Bonaparte, 1963a). PVL Skull lacking the right zygomatic arch, and a right femur. Holotype of Proexaeretodon vincei. Material found in the base of the Ischigualasto beds and described by Bonaparte (1963c). PVL Skull lacking the left zygomatic arch, with an incomplete mandible. PVL Portion of the pelvis, incomplete femur; sacral vertebrae. Specimen found in Paso de Lamas, La Rioja Province. PVL Nasal cavity endocast. Material used for the endocranial study (Bonaparte, 1966a). It was found in the Hoyada Agua de Las Catas, next to Los Palacios, La Rioja Province. PVL Ulna. Material found in the Hoyada Agua de Las Catas, next to Los Palacios, La Rioja Province. PVL Two vertebrae; six incomplete ribs. PVL Incomplete mandible with 5 postcanines; scapula, coracoids; incomplete procoracoids; two humeral fragments. PVL Large skull and mandible; pelvic girdle; indeterminate elements. PVL Anterior portion of mandible with four postcanines. PVL Skull with tooth series; two fragments of mandibles, one with 6 and the other with three worn postcanines; an isolated postcanine. PVL Right pelvic girdle. PVL Large incomplete mandible. 2. Ischignathus sudamericanus Bonaparte, 1963 PVL Incomplete mandible with 6 postcanines. PVL Holotype. Skull, mandible (figure 5), an atlanta! arch, and a dorsal vertebra. PVL Incomplete mandible. 3. Massetognatlms pascuali Romer, 1967 PVL Complete skull and mandible. PVL Complete skull and mandible. PVL Skull and mandible. PVL Complete skull and mandible. PVL Skull, with endocranial cast exposed on the right side. Material prepared for endocranial study (Quiroga, 1980b, fig. 5) PVL Large skull with complete dentition, lacking the right postorbital arch and the otic regions. PVL Endocranial cast. PVL Endocranial cast (figure 7.A). Material prepared for endocranial study (Quiroga, 1979a, figs. 1-2; Quiroga, 1980d, fig. 1). PVL Skull, with endocranial cast exposed at the dorsal and lateral left side. Material prepared for endocranial study (Quiroga, 1980b). PVL Skull; bones of the manus. PVL Mandible; femur and bone fragments. PVL Mandible; vertebrae; scapula; ischia and long bone fragments. PVL Mandible with a complete dentition; isolated vertebrae, ribs; left pelvis. PVL Mandible with a complete dentition; an isolated posteanine. PVL Skull (figures 6A-B) and mandible of a juvenile, with complete upper and lower tooth series; articulated dorsal vertebrae; humerus; proximal portion of the femur; scapula; portion of the pelvis and other postcranial elements. Associated to Gracilisuc/ws. PVL Maxillary fragment with complete postcanine series. Associated to Gracilisuchus. PVL Skull lacking right zygomatic arch. PVL Skull and mandible with a complete dentition. PVL Skull with 13 postcanines, the most posterior of them erupting. PVL Skull and mandible in occlusion. PVL Skull with a complete dentition. PVL Skull prepared to show the nasal septum. PVL Dorsal vertebrae, scapular girdle, humerus, radius, ulna, and carpals. PVL Postcranial elements. PVL Mandible. 4. Andescynodon mendozensis Bonaparte, 1969 PVL 3833 (figure 8.A). Holotype. Incomplete skull with badly preserved teeth. The material has also been studied by Goni and Go in (1987, 1988). PVL 3835.? Small mandible with almost complete dentition. Material studied by Goni and Gain (1988). PVL Skull lacking the anterior portion of the muzzle and the left zygomatic arch; postcranial elements, some of them in a nodule. Material studied by Bonaparte (1969, fig. l.b) and Goni and Goin (1987, 1988). PVL 3890.?Incomplete skull; mandible; two humeri; tibia; fibula; unidentified fragments. PVL 3891.?Four complete mandibles (one with well preserved teeth); a mandible fragment. PVL Skull; mandible; humerus; femur; portion of the pelvic girdle; part of the clavicle; an isolated vertebra; nodule with vertebral column and other postcranial elements. Skull prepared for endocranial study (Quiroga, 1980b, figs. 1-2), and also studied by Goni and Goin (1987, 1988). PVL Skull lacking the left zygomatic arch; a fragmentary muzzle; portion of the maxilla with teeth. Material studied by Goni and Goin (1987, 1988). PVL 3896.? Five mandibles. PVL 3897.? Skull and postcranium. PVL Skull and mandible articulated. Material prepared for endocraneal study (Quiroga, 1980b, fig. 3). PVL Mandibles with teeth; femur; bone fragments. PVL Skull and mandible of a juvenile. PVL 4069 to PVL 4072.? Many complete mandibular rami. Material studied by Goni and Goin (1987, 1988). PVL Skull; mandible (figure 8.B); three articulated vertebrae and one isolated vertebra of a juvenile. Material studied by Goni and Gain (1988).

13 Catalogue of cynodonts in the Institute Lillo collection 475., PVL 4422 to PVL Postcanine teeth; many cranial fragments; five humeri; portion of the pelvis; femur and vertebrae. 5. Rusconiodon mignonei Bonaparte, 1970 PVL Skull with badly preserved teeth. PVL Holotype. Skull. PVL 3892a. Skull with mandible articulated, laterally compressed. PVL 3892b. Skull, lacking the right postorbital bar and the anterior portion of the muzzle. PVL 3892c. Fragment of skull, from the canines to the pterygoids. PVL 3892d. Fragment of the skull, fragment of the pelvis. PVL Skull and mandible articulated. 6. Pascualgnathus polanskii Bonaparte, 1966 PVL Hypodigm. Skull and mandible dorsoventrally crushed, badly preserved. PVL 4416 (figure 9.A). Skull and mandibles articulated but remarkably crushed, connected to the first three cervical vertebrae. CYNOGNATHlDAE Watson, Cynognathus crateronotus Seeley, 1895 PVL 3859 (figure 10). Holotype. Skull and mandible in occlusion, with postdentary bones; humerus, a dorsal vertebra, and unidentified postcranial fragments. PROBAlNOGNATHlDAE Romer, Probainognatlms jenseni Romer, 1970 PVL Skull and mandible in occlusion with endocranial cast. Specimen used in endocranial studies (Quiroga, 1980a, figs. 2-4; Quiroga, 1980c, fig. 1, laminas 1 and 2). PVL Incomplete right mandibular ramus with canine and 6 well preserved postcanines. PVL Incomplete left mandibular ramus with 6 well preserved postcanines. PVL 4447 (figure 11.0) Incomplete left mandibular ramus, with canine and 7 well preserved postcanines. PVL Skull and mandible in occlusion, incomplete and deformed, showing well preserved postcanines. PVL Skull with mandible in occlusion, 23 articulated vertebrae, some of them with ribs; right scapular blade almost complete, portion of the pelvic girdle articulated with sacral vertebrae; right humerus, radius and ulna; femur, tibia, fibula of both sides; a metacarpal and a phalange. Specimen associated in a nodule with PVL 4724 and PVL Material studied by Abdala (1991, 1996b). PVL 4678 (figure 11.C). Skull and mandible in occlusion, the left side distorted. Teeth well preserved, and notably worn. PVL Left femur, tibia and fibula. PVL Fragment of clavicle?, humerus, radius and ulna, right femur, tibia and fibula. PVL Vertebral column and ribs. PVL Skull and mandible, badly preserved. CHINIQUODONTIDAE Huene, Cl1iniquodon theotoniws Huene ( ) PVL Anterior fragment of the skull and mandible in occlusion. Described as Clziniquodon ct. tlzeotonicus by Bonaparte (1966b). PVL Anterior portion of the skull from the posterior border of the palate. Described as Chiniquodon cf. tlzeotonicus by Bonaparte (1966b). PVL Small fragment of the skull, anterior to the orbital border. Described as Chiniquodon cf. tlzeotonicus by Bonaparte (1966b). PVL Right humerus, radio and ulna; proximal fragment of a left humerus; both clavicles articulated to the interclavicle; 8 articulated dorsal vertebrae; five left and one right ribs; and 6 unguial phalanges associated with metacarpals. PVL 4015 (figure 7.B). Skull and mandible prepared for endocraneal and inner ear studies (Quiroga, 1979a; Quiroga, 1979b, figs. 3-5; Quiroga, 1980d, figs. 2-3). PVL Skull prepared for endocranial studies (Quiroga, 1980c, fig. 7). PVL 4444 (figures 12.C-D). Skull slightly deformed in the left orbital region, lacking the left zygomatic arch, with mandible in occlusion. Both upper and lower dentitions are well preserved. PVL Skull and mandible in occlusion, lacking the left postorbital bar with a slight dorsoventral crushing. PVL 4674 (figures 12.A-B). Skull and mandible. PVL Juvenile skull and mandible in occlusion deformed and badly preserved. TRITHELEDONTIDAE Broom, Clmliminia musteloides Bonaparte, 1978 PVL 3857 (figure 13). Holotype. Skull with mandible in occlusion badly preserved. PVL Incomplete skull badly preserved. TRITYLODONTIDAE Cope, cf. Tritylodon PVL Distal portion of humerus; proximal portion of femur, and two dorsal vertebrae articulated.!ncertae SEDIS 12. Cromptodon mamiferoides Bonaparte, 1972 PVL 3858 (figure 14). Holotype. Mandible with 6 postcanines.