THE OCCURRENCE OF CONTOGENYS-LIKE LIZARDS IN THE LATE CRETACEOUS AND EARLY TERTIARY OF THE WESTERN INTERIOR OF THE U.S.A.

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1 Journal of Vertebrate Paleontology 29(3): , September 2009 # 2009 by the Society of Vertebrate Paleontology ARTICLE THE OCCURRENCE OF CONTOGENYS-LIKE LIZARDS IN THE LATE CRETACEOUS AND EARLY TERTIARY OF THE WESTERN INTERIOR OF THE U.S.A. RANDALL L. NYDAM * and BRANDON M. FITZPATRICK { Arizona College of Osteopathic Medicine, Midwestern University, N. 59th Avenue, Glendale, Arizona 85308, U.S.A., rnydam@midwestern.edu ABSTRACT Based on diagnostic jaw and dental material from the Cenomanian middle Paleocene of the western U.S.A., we erect a new fossil lizard taxon, Contogeniidae taxon nov., that contains the following species: Contogenys sloani Estes, 1969 (Maastrichtian early Paleocene, Montana); Contogenys ekalakaensis sp. nov. (middle Paleocene, Montana); Palaeoscincosaurus middletoni Sullivan and Lucas, 1996 (early Paleocene, Colorado); Palaeoscincosaurus pharkidodon sp. nov. (Campanian, Utah); Utahgenys evansi gen. et sp. nov. (Turonian, Utah); and Utahgenys sp. indet. (Cenomanian, Utah). These taxa share unique characteristics of tooth and jaw morphologies (e.g., tooth crowns truncate and bearing longitudinal apical grooves; hypertrophied inferior alveolar canal). Phylogenetic analysis indicates that among squamates, Contogeniidae taxon nov. is most closely related to Xantusiidae. INTRODUCTION Most of the scincomorphan lizards described from the middle and Late Cretaceous of North America are borioteiioideans (i.e., teiids ; see systematic revision of Nydam et al., 2007), a group that includes Chamops and similar taxa and polyglyphanodontines (Estes, 1983; Gao and Fox, 1991; Denton and O Neill, 1995; Nydam, 1999, 2002; Nydam et al., 2007). Previously recognized non-borioteiioidean taxa generally have been referred to, or allied with, the Scincidae, Cordylidae, or Xantusiidae (Estes, 1983; Gao and Fox, 1996; Nydam, 2002). One such non-borioteiioidean is Contogenys sloani Estes, 1969, which was described by Estes (1969) based on jaws collected in Montana, U.S.A., from the Bug Creek Anthills (BCA) locality (mixed late Maastrichtian and early Paleocene) in the Hell Creek Formation and from the Medicine Rocks locality in the Tongue River Formation (middle Paleocene). Because the BCA locality includes both Paleocene and reworked Cretaceous fossils, it is impossible to determine the exact geological age of any specimens from that locality (see discussion in Lofgren, 1995). However, Bryant (1989) reported additional C. sloani specimens from the Flat Creek 5 locality (UCMP V73087), which is exclusively within the Maastrichtian portion of the Hell Creek Formation, thus confirming the presence of the species on both sides of the Cretaceous/Tertiary (K/T) boundary. Estes (1969, 1983) referred Contogenys to?scincidae and Bryant (1989:46) followed suite in her tentative assignment of Contogenys to cf. Scincidae in her list of taxa from the Hell Creek Formation. In their revision of Contogenys, GaoandFox (1996) cited several characters of jaw morphology and dentition that tentatively supported referring the genus to the Xantusiidae. A similar taxon, Palaeoscincosaurus middletoni Sullivan and Lucas, 1996, is known from the early Paleocene of Colorado. The species is represented by seven incomplete jaws, including several fragmentary mandibles preserving articulated dentary * Corresponding author. { Current address: St. John s College, 1160 Camino Cruz Blanca, Santa Fe, New Mexico, 87505, U.S.A. and postdentary elements. Sullivan and Lucas (1996:666) tentatively assigned P. middletoni to?scincidae and noted similarities in dentition and dentary morphologies with Contogenys. Two of the most distinctive characteristics used by Gao and Fox (1996) in their re-diagnosis of Contogenys were the chisellike tooth crowns with anteroposteriorly directed apical grooves and the hypertrophied inferior alveolar canal that results in a shelf-like expansion (= depressed channel of Estes, 1969:3) of the dentary below the posterior portion of the tooth row. This combination of tooth and jaw characters also is present in Palaeoscincosaurus middletoni and in some new lizard jaws recovered from Cenomanian, Turonian, and Campanian horizons in southern Utah. The new specimens represent at least two (and possibly three) new taxa. Additionally, we have identified sufficient morphological differences between previously described specimens of Contogenys sloani from the Hell Creek Formation and from the Tongue River Formation to support erecting a new species of Contogenys for specimens from the latter unit. Further, we propose that C. sloani, P.middletoni, and the new taxa described herein constitute a previously unrecognized clade of lizards that became established by at least the beginning of the Late Cretaceous and persisted through the middle Paleocene. Institutional Abbreviations MCZ, Museum of Comparative Zoology, Harvard University, Boston, Massachusetts, U.S.A.; MNA, Museum of Northern Arizona, Flagstaff, Arizona, U.S.A.; OMNH, Sam Noble Oklahoma Museum of Natural History, Norman, Oklahoma, U.S.A.; UCM, University of Colorado Museum, Boulder, Colorado, U.S.A.; UCMP, University of California Museum of Paleontology, Berkeley, California, U.S. A.; UMNH, Utah Museum of Natural History, Salt Lake City, Utah, U.S.A.; YPM PU, Yale Peabody Museum (Princeton University collections), New Haven, Connecticut, U.S.A. Osteological Terminology We follow Gao and Fox (1996) for most our osteological terminology. However, we have chosen to follow Estes (1983) in identifying the small openings along the lateral surface of the dentary as mental foramina, rather than inferior alveolar foramina sensu Gao and Fox (1996:11), to avoid confusion with the anterior inferior alveolar foramen located in the medial surface of the mandible. 677

2 678 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 29, NO. 3, 2009 Classification Convention We use an unranked hierarchy based on the classification of Estes (1983) for our systematic paleontology (see also Nydam et al., 2007). GEOLOGICAL SETTING The new specimens reported herein were recovered from Upper Cretaceous rocks exposed in and around the Grand Staircase Escalante National Monument (including the Kaiparowits Plateau region) in Garfield and Kane counties, southern Utah, U.S.A. Cretaceous rocks in this region consist of a nearly continuous sequence extending from the Cenomanian through Campanian that represents both near-shore terrestrial and marine depositional environments (Peterson and Waldrop, 1965; Eaton, 1991). Eaton (1991) provided a comprehensive biostratigraphic review of Cretaceous deposits in the region. Specimens discussed below were recovered from three of the terrestrial units: Kaiparowits, Straight Cliffs, and Dakota formations. OMNH locality V5 (Fig. 1) is in the upper part of the Kaiparowits Formation about 630 m above the base of the unit, where it is exposed in The Blues (a region along Utah State Highway 12 between the towns of Escalante and Henrieville). This part of the Kaiparowits Formation is characterized by steep exposures of interbedded gray mudstones and channel sandstones deposited in what has been interpreted as a meandering stream system (Eaton et al., 1987). OMNH localities V6 and V9 are in the lower part of the Kaiparowits Formation approximately 290 m and 310 m, respectively, above the contact with the underlying Wahweap Formation (Eaton et al., 1987). Both localities are in gray sandstones and siltstones that form low terraces and ledges. The Kaiparowits Formation has been dated at Ma based on an 40 Ar/ 39 Ar analysis of volcanic ashes (Roberts et al., 2005), which places the unit within the Campanian. MNA locality 995 and OMNH locality V1404 are in the Smoky Hollow Member of the Straight Cliffs Formation and are located north and southeast, respectively, of the town of Henrieville. The lithology of MNA 995 is characterized by graygreen clays, whereas OMNH V1404 is characterized by green mudstone with clayballs. Both localities are within the barren middle zone of Peterson (1969) and are approximately 15 m above the lignite horizon at the base of the Smoky Hollow Member. Rocks of the Smoky Hollow Member are interpreted as having been deposited across a coastal flood plain during the late Turonian (Eaton, 1991; Eaton et al., 1997). MNA locality 1067 is located in exposures of the Dakota Formation near Cannonville, Utah. The productive horizon is an overbank flood deposit of gray siltstone that is overlain by a thin, orange-tan siderate layer. The Dakota Formation is a Cenomanian-aged near-shore terrestrial unit interpreted as having been deposited during the transgression of the mid-continental seaway that bisected North America during much of the Late Cretaceous (Peterson and Waldrop, 1965; Eaton, 1991). In the Kaiparowits Plateau region, the Dakota Formation is characterized by fine-grained mudstones and siltstones with interbedded, ledge-forming sandstones. SYSTEMATIC PALEONTOLOGY REPTILIA Linnaeus, 1758 SQUAMATA Oppel, 1811 SCINCOMORPHA Camp, 1923 CONTOGENIIDAE taxon nov. Etymology Named for Contogenys Estes, 1969, the first described genus. Type Genus Contogenys Estes, Included Genera Contogenys Estes, 1969; Palaeoscincosaurus Sullivan and Lucas, 1996; and Utahgenys gen. nov. FIGURE 1. Map of localities. A, Bug Creek Anthills (BCA) locality, Montana, Hell Creek Formation, mixed Maastrichtian and early Paleocene (see Lofgren 1995 for review); B, Medicine Rocks locality, Montana, Tongue River Formation, middle Paleocene (see Estes, 1976); C, Alexander Locality, Colorado, Denver Formation, early Paleocene (see Sullivan and Lucas, 1996); D, MNA locality 1067, Utah, Dakota Formation, Cenomanian; E, MNA locality 995, Utah, Smoky Hollow Member of Straight Cliffs Formation, Turonian; F, OMNH locality V1404, Utah, Smoky Hollow Member of Straight Cliffs Formation, Turonian; G, OMNH locality V6, Utah, Kaiparowits Formation, Campanian; H, OMNH locality V9, Utah, Kaiparowits Formation Campanian; I, OMNH locality V5, Utah, Kaiparowits Formation, Campanian. Distribution Cenomanian middle Paleocene, Western Interior of U.S.A. Diagnosis Differs from all other lizard families in the following unique combination of characters: hypertrophied inferior alveolar canal forming shelf-like lateral expansion along posterior portion of dentary; tooth crowns truncated (i.e., squaredoff ); tooth crowns with anteroposteriorly directed apical groove; and lateral expansion of posterior process of maxilla. Differs further from Xantusiidae, including Palaeoxantusia, in having Meckelian canal open along medial face of dentary to the symphysis, but resembles both in having distinct coronoid articulation facet on medial surface of coronoid process on dentary, posteroventral process on dentary distinct and much larger than coronoid process, and posteroventral process on dentary extends back farther than coronoid process. Further similar to xantusiids

3 NYDAM AND FITZPATRICK CONTOGENYS-LIKE LIZARDS 679 in having a distinct, ventrally directed curvature of supradental shelf on maxilla behind tooth row. Remarks The Contogeniidae is erected in recognition of the unique suite of features that unites and distinguishes Contogenys, Palaeoscincosaurus, and Utahgenys gen. nov. from all other known lizards. The characters listed above previously were considered to be diagnostic at the species level for C. sloani (Estes, 1969; Gao and Fox, 1996), but are here interpreted to be diagnostic at a more inclusive level for Contogeniidae. Similarly, characters originally identified by Gao and Fox (1996) as being shared between C. sloani and Xantusiidae are here interpreted as being shared between Contogeniidae and Xantusiidae. Additionally, Gao and Fox (1996:55 56) interpreted a double row of mental foramina along the anterior portion of a dentary (UALVP 29839) of Contogenys sloani as being an individual variant of that taxon, but this feature is present in all specimens of C. sloani and C. ekalakaensis that we observed. A double row of mental foramina are also present on the anterolateral surface of dentaries of Palaeoscincosaurus pharkidodon sp. nov. (OMNH 20265, 33873; see below), but the condition of the mental foramina for the other contogeniid taxa described below cannot be determined due the absence of specimens preserving the anterior region of the dentary. Based on the above distribution, a double row of mental foramina along the anterior portion of the dentary may be an additional, diagnostic character of Contogeniidae. CONTOGENYS Estes, 1969 Type Species Contogenys sloani Estes, Included Species Contogenys sloani Estes, 1969, and C. ekalakaensis sp. nov. Distribution Hell Creek Formation (late Maastrichtian and early Paleocene) and Tullock Formation (middle Paleocene), both in Montana, U.S.A. Revised Diagnosis Contogeniid genus differing from Palaeoscincosaurus and Utahgenys gen. nov. in the following unique combination of features: dentary relatively short anteroposteriorly; 16 or fewer teeth on dentary; and maxillary and dentary tooth shafts anteroposteriorly compressed and medially expanded below crown. Differs from Palaeoscincosaurus in having smaller adult body size (as inferred from relative mandible size), teeth more closely spaced, tooth shafts relatively narrower, apical striae on tooth crowns less prominent or absent, anterior process of coronoid extends anteriorly to a point below posteriormost tooth position on dentary, and minimal overlap between anterior process of coronoid and coronoid lappet of dentary. Differs from Utahgenys in having teeth without tricuspid crowns and with tooth bases less medially expanded. CONTOGENYS SLOANI Estes, 1969 (Figs. 2, 3A F) Contogenys sloani Estes, 1969:figs. 1 5 (original description). Contogenys sloani Estes: Gao and Fox, 1996:fig. 24G, H (revised diagnosis). Holotype MCZ 3681, left dentary preserving five in situ teeth (Estes, 1969:fig. 1a, b; this paper Fig. 3D F). Holotype Locality, Horizon, and Age Bug Creek Anthills (mixed late Maastrichtian and early Paleocene), McCone County, Montana, U.S.A.; Hell Creek Formation. Referred Specimens MCZ 3682, incomplete right maxilla (Fig. 2J K); MCZ 3683, incomplete left dentary (Fig. 2F I); MCZ 3684, incomplete right dentary (Fig. 3A C); OMNH 59221, incomplete left dentary (Fig. 2A E); UALVP nearly complete right dentary (Gao and Fox, 1996:fig. 24G H); UCMP , posterior end of left dentary; UCMP , dentary fragment, side indeterminate; UCMP , incomplete left dentary; UCMP , left dentary fragment. Three dentaries (YPM PU 17035, 17036a, b) originally referred by Estes (1969) to Contogenys sloani are here assigned to a new species of Contogenys (see next species account, below). Distribution Late Maastrichtian early Paleocene, Montana, U.S.A. Hell Creek Formation: Bug Creek Anthills (= OMNH locality V1173) (MCZ ; OMNH 59221; UALVP 29839), mixed late Maastrichtian and early Paleocene, McCone County; UCMP V73087 (UCMP ) and UCMP V77130 (UCMP ), both late Maastrichtian and in Garfield County. Tullock Formation, early Paleocene: UCMP V74122 (UCMP ), Garfield County. Revised Diagnosis Differs from Contogenys ekalakaensis sp. nov. in the following combination of dentary features: more gracile subdental shelf; intramandibular septum extending posteriorly to penultimate tooth position; ventralmost portion of coronoid facet on coronoid process directed anteroventrally; greater degree of hypertrophy of Meckelian canal results in more pronounced, shelf-like lateral expansion along posterior portion of dentary; and tooth crowns lacking striae. Remarks Gao and Fox (1996:56) reported the presence of a small basal foramen for each tooth in Contogenys sloani. Their figure of a right dentary UALVP in medial view (Gao and Fox, 1996:fig. 24H) indeed shows a small opening at the base of each tooth. However, those openings vary in size, particularly height. Additionally, teeth preserved in other dentaries (MCZ 3681, Fig. 3D, F; MCZ 3684, Fig. 3A, C; and OMNH 59221, Fig. 2C, E) and in the only known the maxilla (MCZ 3682, Estes 1969:fig. 2, this paper Fig. 2J, K) of C. sloani demonstrate that not all teeth have basal openings and, for those teeth that do, the openings varying in size like in UALVP We interpret these openings as replacement pits preserved in varying stages of development and do not consider them to be taxonomically informative. In the YPM PU specimens that Estes (1969) referred to Contogenys sloani, both Gao and Fox (1996) and Sullivan and Lucas (1996) identified features that they suggested might indicate those specimens belonged to a new species of Contogenys. The features identified by Gao and Fox (1996) were: deeper Meckelian canal (accommodating a larger splenial); more prominent subdental shelf; and more columnar teeth with striated crowns. The features identified by Sullivan and Lucas (1996) were: closed or nearly closed Meckelian canal and larger subdental gutter; those authors also noted the geologically younger age (middle Paleocene) of the YPM PU specimens. In our examination of Contogenys specimens, we were able to confirm the features listed by Gao and Fox (1996) and identified additional features that also reliably distinguish the middle Paleocene specimens from the lower Paleocene and Maastrichtian specimens. Consequently, we retain the latter specimens (dentaries and one maxilla) in C. sloani and, in the next account, erect a new species of Contogenys for the distinctive middle Paleocene dentaries. CONTOGENYS EKALAKAENSIS, sp. nov. (Fig. 3G N, 4) Contogenys sloani, Estes, 1969 (in part). Etymology For the town of Ekalaka, Montana, which is near the type locality. Holotype YPM PU 17035, complete right dentary preserving seven in situ teeth (Estes, 1969:fig. 4; this paper Fig. 3G I). Holotype Locality, Horizon, and Age Medicine Rocks locality, approximately 19 km north of the town of Ekalaka, Carter County, Montana, U.S.A.; Tongue River Formation; middle Paleocene. Paratypes YPM PU 17036a, incomplete left dentary (Fig. 3J L, Fig. 44); and YPM PU 17036b, incomplete right mandible (Estes, 1969:fig. 5a; this paper Fig. 3M, N).

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5 NYDAM AND FITZPATRICK CONTOGENYS-LIKE LIZARDS 681 FIGURE 3. Comparison of Contogenys sloani Estes, 1969, and Contogenys ekalakaensis sp. nov. A D, Contogenys sloani from the Bug Creek Anthills (mixed late Maastrichtian and early Paleocene), Hell Creek Formation, Montana.: A C, MCZ 3684, incomplete right dentary: A, stereopairs in medial view; B, stereopairs in occlusal view; C, close up of posterior end of tooth row and adjacent bone in medial view. D F, MCZ 3681, holotype, incomplete left dentary: D, stereopairs in medial view; E, stereopairs in occlusal view; F, close up of posterior end of tooth row and adjacent bone in medial view. G N, Contogenys ekalakaensis sp. nov. from the Tongue River Formation (middle Paleocene), Montana: G I, YPM PU 17035, holotype, right dentary: G, stereopairs in medial view; H, stereopairs in occlusal view; I, close up of posterior end of tooth row and adjacent bone in medial view. J L, YPM PU 17036a, paratype, incomplete left dentary: J, stereopairs in medial view; K, stereopairs in occlusal view; L, close up of posterior end of tooth row and adjacent bone in medial view. M, N, YPM PU 17036b, paratype, incomplete right mandible: M, stereopairs in medial view, with suture lines highlighted on left image; N, lateral view. Abbreviations: a, angular; aaf, anterior inferior alveolar foramen; amf, anterior mylohyoid foramen; co, coronoid; d, dentary; sa, surangular; sp, splenial. Scale bars equal 1 mm. Distribution Known only from the holotype locality. Diagnosis Differs from Contogenys sloani in the following combination of dentary features: subdental shelf more robust and more vertical in orientation; subdental gutter deeper; intramandibular septum extending posteriorly to last tooth position; ventral portion of facet on dentary for anterior process of coronoid directed more vertically; and weakly developed lingual striae on tooth crowns. Description The holotype, YPM PU (Fig. 3G I), is a complete right dentary with 15 tooth positions and seven complete teeth. The teeth are chisel-like, with a distinct anteroposteriorly oriented apical groove along the crown. The lingual surfaces of the teeth have weakly developed striae bounded by more fully developed anterior and posterior carinae. The subdental shelf is tall (nearly one-third tooth height) and dorsally concave. The subdental gutter is narrow. The posterior portion / FIGURE 2. Contogenys sloani Estes, 1969, from the Bug Creek Anthills (mixed late Maastrichtian and early Paleocene), Hell Creek Formation, Montana. A E, OMNH 59221, incomplete left dentary: A, stereopairs in occlusal view; B, stereopairs in lateral view; C, stereopairs in medial view; D, close up of posteriormost three teeth in occlusal view; E, close up of posterior portion of dentary in medial view. F I, MCZ 3683, incomplete left dentary: F, stereopairs in occlusal view; G, stereopairs in lateral view; H, stereopairs in medial view; I, close up of posteriormost three teeth in occlusal view. J, K, MCZ 3682, incomplete right maxilla: J, stereopairs in medial view, K, close up of posterior end in medial view. Scale bars equal 1 mm.

6 682 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 29, NO. 3, 2009 FIGURE 4. Magnified stereopairs showing part of the ventral surface of YPM PU 17036a, incomplete left dentary of Contogenys ekalakaensis sp. nov. from the Tongue River Formation (middle Paleocene), Montana, showing postmortem fracture and subsequent displacement of the lateral wall of the Meckelian canal that creates a false closure of the Meckelian canal. Scale bar equals 1 mm. of the Meckelian canal is widely open for articulation with the splenial. The splenial articulation facet on the dentary extends anteriorly just past the midpoint of the tooth row. Forward from this point the Meckelian canal is open to the symphysis only as a narrow slit. The intramandibular septum is fused to the floor of the Meckelian canal and its posteriormost margin extends nearly to the posteriormost tooth position (Fig. 3I). The lateral surface is convex and expanded laterally, such that when viewed in occlusal aspect (Fig. 3H) the posterior portion of the tooth row has the appearance of being deflected medially. The coronoid process of the dentary is tall and overlaps the anterior process of the coronoid. The medial surface of the coronoid process has a deep groove that extends towards the subdental shelf and turns vertically near its termination. This groove is for articulation with the anterior process of the coronoid. The posteroventral process of the dentary is long (Fig. 3G, H) and extends posteriorly well beyond the coronoid process. YPM PU 17036a (Fig. 3J L) is a nearly complete left dentary with 15 tooth positions and five complete teeth. The complete teeth are similar to those of YPM PU and the broken teeth have hollow tooth shafts (Fig. 3K). The Meckelian canal is similar to YPM PU in being widely open posteriorly. The anterior portion of the Meckelian canal has a short section in which the margins are in contact, but not fused (Fig. 3J); however, this contact is an artifact of preservation (see below). The intramandibular septum extends posteriorly to the last tooth position (Fig. 3L). The coronoid and posteroventral processes are missing, but the anterior portion of the groove for the anterior process of the coronoid is present (Fig. 3J) and has a vertical turn as it approaches the subdental shelf. A similar morphology is present in YPM PU YPM PU 17036b (Fig. 3M, N) is an incomplete right mandible preserving the posterior portion of the dentary and the anterior portions of the angular, coronoid, surangular, and splenial. The coronoid is broken just behind the vertical ridge on the medial side of the element (Fig. 3M). The anterior process of the coronoid extends to the posterior portion of the subdental shelf of the coronoid and turns vertically as it tapers to a narrow exposure between the subdental shelf and splenial (Fig. 3M). The preserved portion of the angular is small and has a modest medial exposure (Fig. 3M). The lateral exposure of the anterior process of the coronoid is restricted to a narrow, triangular wedge between the coronoid process of the dentary and surangular (Fig. 3N). The coronoid process of the dentary overlaps the anterolateral surface of the coronoid (Fig. 3N). The specimen also preserves the anterior inferior alveolar foramen, which is bounded anteriorly and dorsally by the dentary and ventrally and posteriorly by a notch in the splenial (Fig. 3M). The anterior mylohyoid foramen opens just behind the anterior inferior mylohyoid foramen. Remarks Gao and Fox (1996) and Sullivan and Lucas (1996) observed that the Meckelian canal of YPM PU 17036a is closed, but not fused, just in front of the anteriormost extent of the articulation facet for the splenial. However, this feature is actually an artifact of postmortem damage to the specimen. The section of the ventral margin of the Meckelian canal that contacts the subdental shelf has broken free from the rest of the lateral wall of the Meckelian canal and rotated medially, so that it now contacts the medial margin of the Meckelian canal (Fig. 4). In life the Meckelian canal in YPM PU 17036a would have been approximately the same width as the undisturbed portions of the Meckelian canal in YPM PU 17035, which means that the two specimens are actually identical in this regard. Gao and Fox (1996) also proposed that differences in the depths of the Meckelian canal potentially differentiated the YPM PU dentaries from the dentaries here assigned to C. sloani. In side-byside comparisons of the relevant dentaries, we saw no appreciable differences in Meckelian canal depth between C. sloani and C. ekalakaensis. PALAEOSCINCOSAURUS Sullivan and Lucas, 1996 Type Species Palaeoscincosaurus middletoni Sullivan and Lucas, Included Species Palaeoscincosaurus middletoni Sullivan and Lucas, 1996, and P. pharkidodon sp. nov. Distribution Kaiparowits Formation (Campanian), Utah, U.S.A., and Denver Formation (early Paleocene), Colorado, U.S.A. Revised Diagnosis Contogeniid genus differing from Contogenys and Utahgenys in the following unique combination of features: tooth crowns with numerous lateral and medial apical striae; teeth more robust and widely spaced; and inferred larger body size. Differs further from Contogenys in having posteriormost tooth on maxilla with shaft shorter than more anterior teeth and posteriormost two or three teeth on dentary with progressively shorter shafts at successively more posterior tooth positions. Remarks Sullivan and Lucas (1996) accurately recognized the need to compare and contrast the morphologies of Contogenys sloani and Palaeoscincosaurus middletoni in their original diagnosis for the latter species, but we were unable to confirm two of the characters they used to describe the structure of the coronoid. The first character is the shared presence of a medial vertical ridge bisecting the coronoid into nearly equal anterior and posterior portions. The only known coronoid for Contogenys is on the incomplete mandible YPM PU 17036b (Fig. 3M, N) that is referred here to C. ekalakaensis sp. nov. However, this specimen preserves only the anterior portion of the coronoid, which means that it is not possible to determine what proportion of the coronoid extended posterior from the medial vertical ridge. Consequently, this feature cannot be compared between Contogenys and P. middletoni. The second problematic character is the build of the coronoid, which Sullivan and Lucas (1996) indicated was more stout in P. middletoni compared to Contogenys. We concur that the coronoid in mandibles of P. middletoni is larger than the incomplete coronoid preserved in the referred mandible YPM PU 17036b of C. ekala-

7 NYDAM AND FITZPATRICK CONTOGENYS-LIKE LIZARDS 683 kaensis sp. nov., but note that all of the former mandibles are distinctly larger than the latter mandible. Relative to overall mandible size, comparable portions of the coronoids in P. middletoni and C. ekalakaensis sp. nov. appear nearly equivalent. PALAEOSCINCOSAURUS MIDDLETONI Sullivan and Lucas, 1996 (Fig. 5) Palaeoscincosaurus middletoni Sullivan and Lucas, 1996: figs Holotype UCM 34621, incomplete left mandible with two in situ teeth (Sullivan and Lucas, 1996:figs. 2A, B; 3A, B; this paper Fig. 5D). Holotype Locality, Horizon, and Age Alexander locality, Arapaho County, Colorado, U.S.A.; Denver Formation; early Paleocene. Paratypes UCM 34623, incomplete left maxilla (Sullivan and Lucas, 1996:fig. 2C, D); UCM 34624, incomplete right mandible (Sullivan and Lucas, 1996:figs. 2E, F; 4A, B; this paper Fig. 5E, F); UCM 34994, articulated right maxilla and incomplete right mandible (Sullivan and Lucas, 1996:fig. 2G); UCM 35064, incomplete right mandible (Sullivan and Lucas, 1996:fig. 2H, I; this paper Fig. 5A C); UCM 35065, incomplete right maxilla (Sullivan and Lucas, 1996:fig. 2J, K); UCM 39543, incomplete left mandible (Sullivan and Lucas, 1996:fig. 2L, M). Distribution Known only from the holotype locality. Revised Diagnosis Differs from Palaeoscincosaurus pharkidodon sp. nov. in the following combination of features: shelflike lateral expansion along posterior portion of dentary less fully developed; dentary and maxillary teeth with lateral apical striae on crowns less well-developed, ridges along anterior and FIGURE 5. Palaeoscincosaurus middletoni Sullivan and Lucas, 1996 from the Denver Formation (early Paleocene), Colorado. A C, UCM 35064, paratype, incomplete right mandible: A, occlusal view; B, close up of anteriormost three teeth in occlusal view; C, medial view. D, UCM 34621, holotype, incomplete left mandible in medial view. E, F, UCM 34624, paratype, incomplete right mandible: E, lateral view; F, occlusal view. Scale bars equal 1 mm.

8 684 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 29, NO. 3, 2009 posterior margins of crowns more pronounced, and shafts below crowns not expanded medially. Remarks The discovery of new fossil specimens reported below that represent a new species of Palaeoscincosaurus necessitates a revised diagnosis of P. middletoni in order to distinguish the two congeners. PALAEOSCINCOSAURUS PHARKIDODON, sp. nov. (Fig. 6) Etymology From the Greek pharcido, meaning wrinkle, and odous, meaning tooth. In reference to the wrinkled appearance of the tooth crowns resulting from abundant striae on the medial and lateral surfaces of the crowns. Holotype OMNH 33855, incomplete left dentary with four in situ teeth (Fig. 6A D). Holotype Locality, Horizon, and Age OMNH locality V9, approximately 26 km southeast of the town of Henrieville, Kane County, Utah, U.S.A.; lower part of Kaiparowits Formation; Campanian. Paratypes OMNH 23861, posterior part of left maxilla with two in situ teeth (Fig. 6G I); OMNH 33873, anterior portion of left dentary (Fig. 6J L). Referred Specimens OMNH 20265, anterior portion of right dentary; OMNH 23762, incomplete left maxilla with three in situ teeth (Fig. 6F); OMNH 25935, bulk collection of seven isolated and unassociated teeth; OMNH 33856, fragment of posterior part of right dentary(?) with one in situ tooth (Fig. 6E); OMNH 63528, incomplete right maxilla with three in situ teeth; OMNH 64194, isolated tooth. Distribution Kaiparowits Formation (Campanian), Utah, U.S.A.: OMNH locality V5 (OMNH and 64194), approximately 13 km northwest of the town of Henrieville, Garfield County; OMNH locality V6 (OMNH and 63528), approximately 22 km southeast of the town of Henrieville, Kane County; OMNH locality V9 (OMNH 23762, 25935, 33855, and 33873), approximately 26 km southeast of the town of Henrieville, Kane County. Diagnosis Differs from Palaeoscincosaurus middletoni in the following combination of features: greater hypertrophy of inferior alveolar canal results in larger, shelf-like lateral expansion along posterior portion of dentary; dentary and maxillary teeth with lateral apical striae on crowns more fully developed, ridges along anterior and posterior margins of crowns less well developed, and tooth shafts below crowns expanded medially. Description The holotype, OMNH (Fig. 6A D), is the posterior portion of a left dentary missing the posteroventral and coronoid processes from the posterior end of the bone and has an eroded subdental shelf. The Meckelian canal is wide posteriorly, narrows anteriorly, and is separated from the inferior alveolar canal by a fused intramandibular septum. The inferior alveolar canal is very wide posteriorly, such that the lateral margin of the posterior dentary is strongly convex and expanded laterally to form a shelf below the parapet (Fig. 6B, C). This expansion tapers anteriorly to such an extent that the anteriormost tooth is nearly flush with the lateral parapet. The lateral surface of the specimen is smooth and preserves a single nutrient foramen ventral to the second preserved tooth. The preserved posterior dorsal portion of the dentary is directed posterodorsally, but the extent of the coronoid process is unknown. The four preserved teeth are robust, with shafts that are expanded below the crown giving the teeth a barrel-like appearance in medial view (Fig. 6A). The second and fourth preserved teeth have deep, circular, basal resorption pits. The tooth crowns are mediolaterally compressed (Fig. 6D) and chisel-like, but with a central apex that is slightly taller than the anterior and posterior margins (Fig. 6A). There is a distinct anteroposteriorly directed apical groove divided by a central process that does not extend above the margins. The lateral margin of the apical groove terminates in weakly developed crests that course medially and basally on the crown. The medial and lateral surfaces of the crown have numerous distinct striae that extend basally for a short distance. The medial striae are slightly more prominent than the lateral striae. OMNH (Fig. 6J L) is the anteriormost portion of a left dentary with a single in situ complete tooth and one incomplete tooth. The lateral surface is smooth and preserves a double row of four mental foramina, with one pair dorsal to the other pair (Fig. 6K). The specimen preserves the anteriormost portion of the Meckelian canal, which is open to the symphysis as a narrow groove. The teeth are procumbent and have narrow tooth shafts lacking the expansion seen in teeth on other dentaries of this species. There is a resorption pit at the base of the anteriormost tooth (Fig. 6J). The crown of the complete tooth has a welldeveloped ridge that forms the lateral margin of the apical groove and extends to form prominent ridges on the anterior and posterior margins of the crown (Fig. 6L). The medial surface of the crown is striated, but the lateral surface is smooth. OMNH (Fig. 6G I) preserves the posterior portion of a left maxilla with two in situ teeth. The specimen is from a slightly larger individual than those represented by the other specimens, but the morphology of the teeth is indistinguishable. The posterior process (= jugal wedge of Estes, 1983) of the element is missing, but it is evident from what remains that it projected posterolaterally. The preserved portion of the facial process is short, smooth laterally, and ascends steeply from the posterior process. A narrow, oval (in cross section) posterior dorsal alveolar canal is exposed posteriorly at the broken posterior process. The lateral surface is smooth and preserves a single nutrient foramen that opens posterolaterally. There is a welldeveloped, subcircular resorption pit at the base of the posteriormost tooth. That tooth is slightly larger and taller than the anterior tooth. OMNH (Fig. 6F) is an incomplete left maxilla with three in situ teeth. This specimen is from an individual similar in size to that represented by the holotype (OMNH 33855). The posterior process is broken, but it clearly was expanded posterolaterally. Each successively more posterior tooth is slightly more massive than the preceding tooth. There is a large resorption pit at the base of the posteriormost preserved tooth and a smaller resorption pit at the base of the anteriormost tooth. UTAHGENYS, gen. nov. Etymology From Utah, state from which all known specimens were collected, and from the Greek genys, meaning jaw; in reference to the similarities in jaw and tooth morphologies to Contogenys. Type Species Utahgenys evansi gen. et sp. nov. Included Species Utahgenys evansi gen. et sp. nov., and Utahgenys sp. Distribution Dakota Formation (Cenomanian) and Smoky Hollow Member of Straight Cliffs Formation (Turonian), both in Utah, U.S.A. Diagnosis As for type species (see account, below). UTAHGENYS EVANSI, gen. et. sp. nov. (Fig. 7A P) Etymology In recognition and honor of Dr. Susan E. Evans for her numerous contributions to the study of Mesozoic lizards. Holotype MNA V10014, incomplete right dentary preserving one in situ tooth (Fig. 7A D). Holotype Locality, Horizon, and Age MNA locality 995, approximately 7.5 km northeast of the town of Henrieville, Garfield County, Utah, U.S.A.; Smoky Hollow Member of Straight Cliffs Formation; Turonian.

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10 686 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 29, NO. 3, 2009 Paratypes MNA V10025, incomplete left dentary with two in situ teeth (Fig. 7H J); MNA V10061, posterior portion of right dentary with two in situ teeth (Fig. 7E G); OMNH 64156, posterior portion of left maxilla with three in situ teeth (Fig. 7K M). Referred Specimens MNA V9127, incomplete right maxilla; MNA V10021, indeterminate jaw fragment; MNA V10023, incomplete maxilla; MNA V10024, incomplete right maxilla; MNA V10060, incomplete right maxilla; MNA V10116, incomplete right maxilla (Fig. 7N); MNA V10117, incomplete left maxilla; OMNH 64154, incomplete left dentary (Fig. 7O, P); OMNH 65155, incomplete left dentary; OMNH 64157, incomplete right maxilla; OMNH 64158, incomplete right maxilla; OMNH 64159, incomplete dentary; OMNH 64160, incomplete right dentary; OMNH 64195, incomplete left maxilla; OMNH 64196, incomplete right maxilla; UMNH VP18042, incomplete right dentary. Distribution Smoky Hollow Member (Turonian) of Straight Cliffs Formation, Utah, U.S.A.: MNA locality 995 (= OMNH locality V843 and UMNH VP locality 129) (MNA V9127, V10014, V10021, V10023 V10025, V10060, V10061, V10116, V10117; OMNH 64154, 64155, ; UMNH VP 18042), approximately 7.5 km northeast of the town of Henrieville, Garfield County; OMNH locality V1404 (OMNH 64195, 64196), approximately 13 km southeast of the town of Henrieville, Kane County. Diagnosis Contogeniid species differing from Contogenys sloani, C. ekalakaensis, Palaeoscincosaurus middletoni, and P. pharkidodon in having tooth crowns distinctly tricuspid and bearing fewer and more widely spaced apical striae. Differs further from Contogenys sloani and C. ekalakaensis sp. nov. in having an intramandibular septum with small posterior projection (condition not known for either species of Paleoscincosaurus). Description Three specimens are especially useful for documenting the structure of the dentary. The holotype, MNA V10014 (Fig. 7A D), is an incomplete right dentary preserving the posterior portion of the element. The inferior alveolar canal is large and separated from the Meckelian canal by a fused intramandibular septum. There is a small, pointed, posteriorly directed process on the posterior margin of the intramandibular septum. The single tooth preserved on MNA V10014 is an unerupted replacement tooth (Fig. 7A, C). This tooth has a weakly tricuspid crown with a pronounced apical groove that occupies most of the apex of the crown and is divided into anterior and posterior halves by an apically directed central process. The medial and lateral borders of the apical groove are similar in size and in anteroposterior length. The medial surface of the tooth crown has well-developed striae. The second specimen, MNA V10061 (Fig. 7E G), is an incomplete right dentary from a smaller individual, which we interpret as having been ontogenetically younger, than that of the holotype. MNA V10061 preserves the posterior portion of the element, including the last two teeth in the tooth row. Both teeth are pleurodont and have apical grooves, but otherwise are too worn to assess other morphological details. Behind the preserved portion of the tooth row is an incomplete coronoid process that projects posterodorsally. On the medial surface of this process and just behind the tooth row there is a distinct facet for the anterior process of the coronoid (Fig. 7E). The intramandibular septum is broken and missing from MNA V10061, but the lateral surface below the lateral parapet is expanded and forms a shelf below the tooth row (Fig. 7F, G). The third informative specimen, MNA V10025 (Fig. 7H J), is an incomplete left dentary preserving the middle portion of the element. The two preserved teeth (Fig. 7H, J) are pleurodont and have slightly mediolaterally expanded shafts. There are small nutrient foramina at the bases of the preserved teeth. The tooth crowns are weakly tricuspid with a prominent apical groove. The lateral apical ridge forming the lateral margin of the apical groove is anteroposteriorly longer than that forming the medial margin and it is continuous with the crests that border the anterior and posterior margins of the crown. The lateral apical ridge is also medially displaced at its midpoint. The apical groove is divided into anterior and posterior halves by the low, central cusp of the tooth. Striae are present on both the medial and lateral surfaces of the crown, but are more prominent and numerous on the medial surface. The subdental shelf is not tall, being less than one-half the height of either preserved tooth. The subdental gutter is narrow. The Meckelian canal is open along the length of the specimen, but tapers anteriorly to a narrow, slit-like groove. Articulation surfaces on the margins of the Meckelian canal for the splenial are smooth and bear a medially displaced groove on the ventral margin of the subdental shelf. Anterior to the articulation with the splenial, the Meckelian canal is restricted to a narrow, slit-like opening. Two informative maxillae are available. OMNH (Fig. 7K M) is an incomplete left maxilla preserving the posteriormost three teeth and the proximal portion of the posterior process. The posterior process is directed laterally and dorsally, but is missing its distalmost portion. The lateral surface is pitted and eroded, but smooth immediately above the lateral parapet. The teeth are pleurodont, tricuspid, and have distinct apical grooves and medial and lateral striae. MNA V10024 (Fig. 7N) is the posterior portion of a right maxilla that also preserves a laterally and dorsally directed posterior process. Unlike the posterior process of OMNH 64156, the posterior process of MNA V10024 has a distinct, medially directed groove that, in life, presumably accommodated the anterior, or maxillary, process of the jugal. The anteriormost tooth of MNA V10024 has a tall, oval basal resorption pit and the second tooth has a small, basal nutrient foramen. OMNH (Fig. 7O, P) is an incomplete left dentary preserving three teeth. These teeth are similar to those described above, but differ in that a moderate amount of basal cementum is clearly evident and the teeth become gradually larger in each successively more posterior position. UTAHGENYS sp. indet. (Fig. 7Q, R) Specimen MNA V9113, incomplete left dentary with two in situ teeth (Fig. 7Q, R). Distribution MNA locality 1067, approximately 1 km west of the town of Cannonville, Garfield County, Utah, U.S.A.; Dakota Formation; Cenomanian. Description MNA V9113 is an incomplete left dentary that preserves an open Meckelian canal that narrows anteriorly (Fig 7Q). The preserved subdental shelf is short posteriorly and taller anteriorly, but not higher than one-half the height of either of the preserved teeth. The subdental gutter (Fig. 7R) is narrow and well-defined. The teeth are nearly identical to those described above for Utahgenys evansi gen. et sp. nov., except there are no striae on the lateral surface of the crown. The anteriormost preserved tooth has a tall, basal oval resorption pit. All tooth bases are surrounded by a moderate amount of cementum. / FIGURE 6. Palaeoscincosaurus pharkidodon sp. nov. from the Kaiparowits Formation (Campanian), Utah. A D, OMNH 33855, holotype, incomplete left dentary: A, stereopairs in medial view, with arrow indicating tooth shown in D ; B, stereopairs in occlusal view; C, stereopairs in lateral view; D, close up in occlusal and slightly medial view of tooth indicated by arrow in A. E, OMNH 33856, fragment of posterior part of right dentary (?), close up in oblique occlusal and medial view of sole in situ tooth. F, OMNH 23762, incomplete left maxilla, medial view. G I, OMNH 23861, paratype, incomplete left maxilla: G, medial view; H, lateral view; I, occlusal view. J L, OMNH 33873, paratype, incomplete left dentary: J, medial view; K, lateral view; L, occlusal view. Scale bars equal 1 mm.

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12 688 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 29, NO. 3, 2009 Remarks It is not clear if the lack of lateral striae on the tooth crowns of MNA V9113 is sufficient to diagnose a new species. For this reason, we withhold a species-level referral pending the recovery of additional specimens. PHYLOGENETIC ANALYSIS A phylogenetic analysis was performed using PAUP 4.0b (Swofford, 2003) in order to examine the relationships of contogeniids with representative lepidosauromorphans. To test for monophyly of Contogeniidae we scored Contogenys sloani, C. ekalakaensis sp. nov., Palaeoscincosaurus middletoni, P. pharkidodon sp. nov., and Utahgenys evansi gen. et sp. nov. separately. Additionally, to avoid artificially weighting the results of the phylogenetic analysis in favor of monophyly for Contogeniidae, we did not add to the data set any of the characters used above in the generic or specific diagnoses. We used Evans and Chure s (1998) data set, because it provides a comprehensive character matrix for testing new taxa within Squamata. Because contogeniid species are known only from jaws (maxillae and mandibles), those taxa could be scored only for a maximum 20 of 212 characters (Appendix 1) or approximately 10% of the potential data set. In addition to the five fossil contogeniid species, we also included in our analysis a sixth fossil species Paracontogenys estesi Schatzinger ex Estes 1983 (taxon name proposed by Schatzinger, 1975, but not formally published until included in Estes, 1983; see discussion in Gao and Fox, 1996), a late Eocene squamate known by isolated dentaries, maxillae, and frontals from California that is relevant to our study because it has been compared with Contogenys and xantusiids by some authors (e.g., Schatzinger, 1975; Estes, 1983). Except for the monospecific Lanthanotus, all extant squamate taxa used in our analysis are multi-specific and were scored at the generic level (Varanus) or higher (e.g., Iguania, Gekkota, Scincidae, Anguidae) in the same manner as by Evans and Chure (1998; this paper Appendix 2). Rhynchocephalia was designated as the outgroup taxon. A branch-and-bound search was performed with the following assumptions: all characters unordered and equally weighted; gaps in data (? ) treated as missing data; and multistate taxa treated as polymorphisms. Our analysis resulted in two equally most parsimonious trees (tree length 772, CI = 0.812, RI = 0.572), differing only in the position of Scincidae (sister taxon of Cordylidae versus sister taxon of clade containing Teiioidea + (Contogeniidae + (Xantusiidae +Paracontogenys))). A strict consensus tree (Fig. 8) was generated from the two shortest trees. Monophyly of the clade containing Contogeniidae + (Xantusiidae + Paracontogenys) is supported by three characters: 51-1, 57-1, and 59-2 (see discussion below). Monophyly of the Contogeniidae is supported by one synapomorphy: Meckelian canal subdivided by a well-developed intramandibular septum that extends to near the posterior end of the dentary (character 48-1). That synapomorphy also occurs convergently in the Anguimorpha. Differences in assumptions about rates of character state transformations (e.g., ACCTRAN versus DELTRAN) did not affect tree topologies or character state distributions. A Bootstrap analysis (Fig. 8) returned values below 50% for the node linking Contogeniidae and (Xantusiidae + Paracontogenys) and for the node at the base of Contogeniidae. Those bootstrap values are not unexpected considering the greater amount of missing data typically associated with fossil versus extant taxa, but are higher than values for some nodes supporting clades that contain extant taxa with no missing data. To summarize, the key findings of our phylogenetic analysis are: (1) Contogeniidae is monophyletic; (2) intra-relationships within Contogeniidae are unresolved; and (3) Contogeniidae is the sister taxon of an unnamed clade containing Xantusiidae and Paracontogenys. There are two reasons why intra-relationships within Contogeniidae are unresolved: (1) the large amount of missing data for the five contogeniid species and (2) in order to test the position of the contogeniids independent of autapomorphic characters, we chose not add to the analysis any of the characters used in our diagnoses for the contogeniid genera or species. DISCUSSION Character Analysis Although there is a significant amount of missing data for each of the contogeniid taxa the results of our analysis are still robust enough (e.g., relatively high consistency index) to permit a brief discussion of the relevant characters. Two of the three synapomorphic characters (our characters 51-1 and 59-2) that support a sister taxon relationship between Contogeniidae and (Xantusiidae + Paracontogenys) describe the relationship between the coronoid and the dentary. Character 51-1 is the presence of a large coronoid process of the dentary and character 59-2 describes the coronoid process of the dentary covering the anterior process of the coronoid. All of the contogeniid taxa except Palaeoscincosaurus pharkidodon and Utahgenys sp., neither of which are known by dentaries that preserve the relevant portion have a prominent coronoid processes. Also, specimens representing Contogenys ekalakaensis and Palaeoscincosaurus middletoni include articulated mandibles that clearly show the overlap of the coronoid process of the dentary onto the anterior process of the coronoid. Though no articulated mandibles are available, preserved dentaries of C. sloani and U. evansi have a distinct facet on the medial surface of the coronoid process that indicates the process also laterally overlapped the anterior process of the coronoid in those species. Based on our analysis, characters 51-1 and 59-2 secondarily arose in Cordylidae and some Scincidae, or alternatively, represent scincomorphan characters secondarily lost in Teiioidea (scored as 51-0 and 59-1). We favor the former alternative, because it does not require a reversal for either character. The third synapomorphic character (57-1) is the shared posterior extension of the splenial, but it must be cautioned that for the fossil taxa included in our analysis this character could only be scored for C. ekalakaensis and P. middletoni. Our analysis indicates that this apomorphy independently arose within Varanoidea, Amphisbaenia, and some iguanians. All three of the synapomorphies that we identified above as supporting a close relationship between Contogeniidae and Xantusiidae are aspects of mandibular morphology. Likewise, previous referrals of Contogenys sloani sensu lato (Estes, 1969, 1983) and Palaeoscincosaurus middletoni (Sullivan and Lucas, 1996) to Scincidae were also based mostly on mandibular characteristics. As noted by Sullivan and Lucas (1996) there are no / FIGURE 7. Utahgenys gen. nov. from southern Utah. A P, Utahgenys evansi gen. et. sp. nov. from the Smoky Hollow Member (Turonian), Straight Cliffs Formation: A D, MNA V10014, holotype, incomplete right dentary: A, ventral view, with arrow indicating posterior process on intramandibular septum; B, medial view; C, oblique occlusal and medial view; D, close up of tooth crown in oblique occlusal and medial view. E G, MNA V10061, paratype, incomplete right dentary: E, stereopairs in medial view; F, stereopairs in occlusal view; G, stereopairs in lateral view. H J, MNA V10025, paratype, incomplete left dentary: H, medial view; I, oblique ventral and medial view; J, close up of teeth in occlusal view. K M, OMNH 64156, paratype, left maxilla: K, medial view; L, lateral view; M, occlusal view. N, MNA V10116, incomplete right maxilla in medial view. O, P, OMNH 64154, incomplete left dentary: O, medial view; P, occlusal view. Q, R, Utahgenys sp. from the Dakota Formation (Cenomanian), Utah, MNA V9113, incomplete left dentary: Q, medial view; R, occlusal view. Scale bars equal 1 mm, unless noted otherwise on figure.