Paleobios 35: 1–8, December 22, 2018 Paleobios

PaleoBios 35: 1–8, December 22, 2018 PaleoBios

OFFICIAL PUBLICATION OF THE UNIVERSITY OF CALIFORNIA MUSEUM OF PALEONTOLOGY

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ADAM D. MARSH (2018). A new record of Dromomeron romeri Irmis et al., 2007 (Lagerpetidae) from the Chinle Formation of Arizona, U.S.A.

Cover: Figure 2 illustrating distal tarsals of dinosauromorphs from the Triassic of Arizona, U.S.A. Citation: Marsh, A.D. 2018. A new record of Dromomeron romeri Irmis et al., 2007 (Lagerpetidae) from the Chinle Forma- tion of Arizona, U.S.A. PaleoBios, 35. ucmp_paleobios_42075. A new record of Dromomeron romeri Irmis et al., 2007 (Lagerpetidae) from the Chinle Formation of Arizona, U.S.A.

ADAM D. MARSH

Petrified [email protected] National Park, 1 Park Road #2217 Petrified Forest National Park, AZ 86028

The relatively recent discovery and contextualization of silesaurid and lagerpetid dinosauromorphs has led to a revolution in understanding the early evolutionary history of the dinosaurian lineage. Lagerpetids

areDromomeron known from gregorii North America and South America in Middle and Upper Triassic rocks, especially the Chinle Formation of New Mexico and the Dockum Group of Texas. Until now, only a single specimen of on Ward Terrace in thewas Navajo known Nation from of the Arizona Upper is Triassic referred Chinle to Dromomeron Formation ofromeri. Arizona. MNA However, V7237 reprea new- lagerpetidsents the youngest astragalus radioisotopically-dated specimen (MNA V7237) record from theof Lagerpetidae, Owl Rock Member indicating of the that Chinle D. Formationromeri persisted found

Keywords:throughout Upperthe entire Triassic, Norian Chinle (Otischalkian Formation, into Dinosauromorpha, the Apachean) in Lagerpetidae, North America. Dromomeron

INTRODUCTION et al. 2009a, 2010, Nesbitt 2011, Nesbitt and Ezcurra Historically, interpretations of the vertebrate assem- 2015, , Baron and Williams 2018). More blages within the Upper Triassic Chinle Formation of profoundly, discoveries at exceptionally well-sampled Arizona emphasized a diverse group of ‘thecodontians,’ NorianMarsh sites suchet al. 2016as the Hayden Quarry at Ghost Ranch, now a paraphyletic group comprising pseudosuchian New Mexico show that non-dinosaur dinosauromorphs archosaurs (aetosaurs) and non-archosaur archosauro- not only co-occurred with their dinosaurian relatives, but morphs (phytosaurs), with only two coeval representa- also may have been more diverse ( , Irmis tive dinosaur groups (herrerasaurids and coelophysoids) et al. 2007, Nesbitt et al. 2009b) (Fig. 1) . This includes (e.g., Camp 1930, Colbert 1947, 1989, Long and Murry the Lagerpetidae , a cladeEzcurra of non-dinosau 2006 - 1995). However, more recent discoveries of dinosaurs riform dinosauromorphs that comprises Lagerpeton and non-dinosaur dinosauromorphs (e.g., Irmis et al. chanarensis Romer,Arcucci, 1971 from1986 the Chañares Formation 2007a, Nesbitt et al., 2009a, 2009b, Nesbitt and Ezcurra, of Argentina (Sereno and Arcucci 1994a), an unnamed 2015, Lessner et al., 2018) from the southwestern United taxon from the Ischigualasto Formation (Martinez et States have cast more light on the diversity of Dinosauro- al. 2012), Ixalerpeton polesinensis morpha Benton, 1985 and its early evolutionary history from the Santa Maria Formation of Brazil, and three up to the end-Triassic extinction. species within the genus DromomeronCabreira Irmis et al.,al., 20072016: The alpha taxonomy of coelophysoids within the D. romeri Irmis et al., 2007 and D. gregorii Nesbitt et al., Chinle Formation and other Upper Triassic sedimentary 2009a - Arizona, New Mexico, and Texas, and D. gigas Martinez stood, and the presence of herrerasaurids in the Upper from fromthe Chinle the Quebrada Formation del and Barro Dockum Formation Group of rocksTriassic in ofwestern North AmericaNorth America is now isdoubted still not based well underon the Brazil. A lagerpetid referred to D. romeri is present in the reinterpretation of holotype specimens and a more Chinleet al., 2016 Formation of the Eagle Basin in Colorado (Small comprehensive understanding of the suite of character 2009, Small and Martz 2013). Hypothetical relationships states that diagnose avemetatarsalian clades (Nesbitt L. chanarensis and

within Lagerpetidae generally reflect Citation: Marsh, A.D. 2018. A new record of Dromomeron romeri Irmis et al., 2007 (Lagerpetidae) from the Chinle Formation of Arizona, U.S.A. PaleoBios, 35. ucmp_paleobios_42075. Permalink: https://escholarship.org/uc/item/8w5755sg Copyright: Items in eScholarship are protected by copyright, with all rights reserved, unless otherwise indicated. 2 PALEOBIOS, VOLUME 35, DECEMBER 2018

Age (Ma)

203 A Garza County, B Ghost Ranch, NM Randall County, TX 204 northern AZ RHAETIAN Apachean 205 MNA composite Argtentina 206 795 1000 km (C) 207 upper Eagle Basin, CO Owl Rock Member 208 * ‘siltstone’ member 209

210 SQ Chinle Formation * DMNH QdP 692 211 QdP, ASRH, VP

H3 Chinle Formation 212 ‘red siltstone’ member Petrified Forest Member Revueltian * Formation del Barro Quebrada BR

213 Petrified Forest Member * middle 214 MOTT 3898 DMNH 692 215 * Formation Canyon Cooper Poleo Ss 216 NORIAN 217 CMNA 795 H3, Sonsela Member SQ 218 * UCMP A269 lSC MOTT 219 3624 MOTT 3898, * MOTT 3624, Chinle Formation UCMP southern Brazil MOTT 2000/ MOTT 3869 220 A269 TMM 31100 * 500 km Adamanian 221 Howard County, TX lower 222

223 * lSC Blue Mesa Member 224

225 * MOTT 2000/ MOTT TMM 31100 3869 226 *

227 City Formation Colorado 228 *

Mesa Redondo Member

229 Formation Caturrita D Boren RanchBoren sandstones PVSJ 883 Otischalkian 230 Ischigualasto Formation Ischigualasto

231 * VP

232 Los CARNIAN

Rastros Fm 233

Moenkopi Formation * BR 234 *

235

236 other lagerpetids ~ * ASRH Chanares Formation Chanares 237 MariaSanta Formation

Figure 1. See caption on top of page 3. MARSH—DROMOMERON ROMERI FROM THE CHINLE FORMATION OF ARIZONA, USA 3

Figure 1. Relative stratigraphic locations of fossil localities. A. Adapted from Riggs et al. 2003, Martz 2008, Irmis et al. 2011, Ra- mezani et al. 2011, 2014, Martinez et al. 2012, Mariscano et al. 2015, , Ezcurra et al. 2017, , Langer et al. 2018, Lessner et al. 2018). B, C. Geographic distribution of lagerpetids. D. Hypothetical relationships within Lager- petidae from Müller et al. (2018 Sarigül 2016 Martz and Parker 2017 of lagerpetid specimens. Tan color represents the Navajo Nation. Silhouette of Dromomeron by Nobu Tamura, used under the Cre- ). Asterisks indicate radiometrichttp://creativecommons.org/licenses/by-sa/3.0/ dates, and silhouettes indicate approximate stratigraphic position ativeAbbreviations Commons: Attribution-ShareAlikeASRH, A.S.R. Hill; BR, Buriol 3.0 Unported ravine; H3license ([ lSC, lower Sunday Canyon; QdP, Quebrada]). Vector del maps Puma; of SQNorth, Snyder America, Quarry; Central VP, ValleAmerica, Pintado. and South America were used from [FreeVectorMaps.com]; Materials and Methods for full links. , Hayden quarry #3; I. polesonensis as early members of the Lagerpetidae, the (Fig. 1A, C). Preparation of this material was accom- Dromomeron clade being more derived with respect to plished with “airscribe and carbon needle” in addition the unnamed taxon from the Ischigualasto Formation Kirby 1991, p. (Langer et al. 2017, Nesbitt et al. 2017, Müller et al. 2018) 32). The lagerpetid specimen from MNA 795 (see below) (Fig. 1D). Stratigraphic and geographic locations of these wasto unknown found with adhesives unionid and bivalves consolidants (Antediplodon ( cf. cris- lagerpetids are shown in Fig. 1. tonensis [ , MNA N9282), partial paramedian With the exception of a referred specimen from the osteoderms of the aetosaur, Typothorax coccinarum Cope, Placerias Quarry near St. Johns, Arizona, the fossil record 1875 (e.g.,Meek MNA 1875] V5583), and pseudopalatine phytosaur of lagerpetids from the Chinle Formation of Arizona squamosals (e.g., MNA V7143). Much of the collection is depauperate compared to the Chinle Formation in - New Mexico, where the Hayden Quarry at Ghost Ranch tifying Ornithischia Seeley, 1887, Rauisuchidae Huene, D. romeri, and 1942,from this Postosuchus locality includes Chatterjee, field 1985 and ,collection or Sphenosuchidae tags iden the nearby Snyder Quarry also preserves a Dromom- Huene, 1942, but an apomorphy-based approach to iden- eronpreserves astragalocalcaneum associated skeletal (Irmis remains et al. of2007, Nesbitt et Bell et al. 2004, Nesbitt et al., 2007, Nesbitt al. 2009b, Smith et al. 2018) (Fig. 1). Described here is , Bell et al. 2010) can only constrain a new specimen of Lagerpetidae referable to D. romeri mosttification of these ( specimens to the level of Archosauria from the Chinle Formation of Arizona at Ward Terrace and Stocker, except2008 for partial shuvosaurid limb bones

Member on Ward Terrace may represent the youngest Cope, 1869 - on the Navajo Nation. The specimen from the Owl Rock ers(e.g., upon MNA request. V5615). More precise locality information is provides further evidence for the long and geographically repositedVector mapsat MNA of andNorth is availableAmerica, toCentral qualified America, research and spreadknown lagerpetidstratigraphic in North range America, of the lagerpetid if not worldwide, fossil record. and South America were used from [https://freevectormaps. Institutional abbreviations—DMNH, Denver Mu- com/world-maps/north-america/WRLD-NA-01-0002 seum of Natural History, Denver, Colorado; GR, Ruth [https://freevectormaps.com/world-maps/central-amer- Hall Museum of Paleontology, Ghost Ranch, New Mexico; ica/WRLD-CAM-01-0002 https://freevectormaps.], MNA, Museum of Northern Arizona, Flagstaff, Arizona; com/world-maps/south-america/WRLD-SA-01-0002 MOTT, Museum of Texas Tech locality; NMMNH, New ], and [ Mexico Museum of Natural History and Science, Albu- SYSTEMATIC PALEONTOLOGY ]. querque, New Mexico; PEFO ARCHOSAURIA sensu PVSJ, Museo de Ciencias Naturales, Uni- AVEMETATARSALIA sensu ORNITHODIRA Cope, 1869 sensu Nesbitt, 2011 versidad Nacional de San Juan,, SanPetrified Juan, Argentina; Forest National TMM, DINOSAUROMORPHABenton, 1999 sensuNesbitt, 2011 VertebratePark, Arizona; Paleontology Laboratory, University of Texas, LAGERPETIDAEGauthier, 1986 sensu Nesbitt et al., 2017a Austin, Texas; TTU-P, Museum of Texas Tech University DROMOMERONBenton, ROMERI 1985 Sereno, 1991 UCMP, Museum of Pale- Arcucci, 1986 Nesbitt et al., 2009 Irmis et al., 2007 Paleontology, Lubbock, Texas; Referred Specimen andFig. 2A–ILocality—MNA V7237, par- ontology, UniversityMATERIALS of California, AND METHODS Berkeley, California. tial left astragalus (Ceratosauria in Kirby 1991) (Fig. 2A, The specimen described here from MNA 795 was col- D, G); locality MNA 795 (Fig. 1C), Billingsley Southeast; lected as a part of a project by crews from the MNA in the - 1980s on the Navajo Nation and was included in Randy Kirby’s thesis on the Upper Triassic assemblages in the OwlNorian Rock (<208 Member Ma, Ramezani of Chinle Formationet al. 2011 ).along This Ward locality Ter is Kirby 1991) race; Badger Spring, AZ USGS 7.5 minute quadrangle;).

Owl Rock Member of the Chinle Formation ( most likely Apachean in age (Martz and Parker, 2017 4 PALEOBIOS, VOLUME 35, DECEMBER 2018

pap pap as fo as ca ca A B C

fo aap amr fo aap amr pap aap aap fo amr D E F ca as as ca aap pap amr pap fo fo fo amr G H I

as Figure 2. A, D, G. Images and drawings of the left astragalusca of Dromomeron romeri from Ward caTerrace, as MNA V7237. B, E, H (reversed). Drawing of the right astragalocalcaneum of D. romeri, GR 223 (paratype). C, F, I. Drawing of the left astragalus and calcaneum of Dilophosaurus wetherilli, UCMP 37302 (holotype). Specimens in proximal (A–C), anterior (D–F), and posterior view between MNA V7237 and GR 223. Abbreviations: aap, anterior ascending process; amr, anteromedial ridge; as, astragalus; ca, (G–I).calcaneum; Dashed ctf lines indicate broken marginsfo, foramen; and papblack, posterior rectangles ascending indicate whichprocess. region Scale of bars=1 the astragalus cm. is preserved in common

, crista tibiofibularis; Description and Rationale for Assignment—MNA and posterior ascending processes found in lagerpetids. V7237 belongs to the Lagerpetidae because it preserves Early dinosaurs such as Chindesaurus bryansmalli Long a posterior ascending process on the astragalus (Sereno and Murry, 1995, Coelophysis bauri Cope, 1887 (Colbert and Arcucci 1994b, Nesbitt et al. 2009b, character 355 in 1989), and Dilophosaurus wetherelli Welles, 1970 (Welles Nesbitt 2011). This specimen can be referred to Drom- 1954, 1984 omeron romeri the anterior ascending process is especially tall and of a large crest or ridge on the anteromedial edge of the pyramidal in) lackneotheropods the posterior (Fig. ascending 2F). A foramen process, passes and astragalus (Irmis based et al. on 2007 the presence, Nesbitt etof al.the 2009b broken). base through the top of the posterior process of MNA V7237 MNA V7237 in the same place as that of the paratype specimen of D. romeri, GR 223 (Nesbitt et al. 2009a), illustrated in to the astragalusis as broken it is in laterallyother lagerpetids, and medially pterosaurs, so it is Figure 2B, E, and H for comparison. Another foramen andimpossible coelophysoid to determine theropods if the (calcaneumIrmis et al. was 2007 co-ossified, Nesbitt penetrates the posterior surface of the anterior ascend- et al. 2009a) (Fig. 2). MNA V7237 is mediolaterally ing process in MNA V7237, which is also shared in other dinosauromorphs (Nesbitt 2011, Langer et al. 2013) (Fig. ornithodiran archosaurs (Langer et al. 2013, Nesbitt et 2A–C). The prominent anteromedial ridge unique to D. al.elongate 2017) and(Fig. roller-shaped 2D, F), and it ventrallyis easy to like understand that of other why romeri is sheared near its base in this specimen, but it Kirby 1991) was obviously a large structure that was connected to - the medial side of the posterior ascending process by morphit was originallyastragali. MNAidentified V7237 as preserves a theropod both ( the anterior an additional low ridge (Irmis et al. 2007, Nesbitt et al. owing to the superficial similarity of many dinosauro MARSH—DROMOMERON ROMERI FROM THE CHINLE FORMATION OF ARIZONA, USA 5

2009a) (Fig. 2A). This ridge divides the tibial facet into (Small 2009, Langer et al. 2013, Small and Martz 2013) (Fig. 1A, C). However, another specimen referred to D. is present in GR 223 (Fig. 2A, B). The anteromedial corner romeri is reported from the lower Sunday Canyon site in anterolateral and posteromedial basins, much like what the lower part of the Cooper Canyon Formation of Garza tibial facet is a single large basin (Nesbitt et al. 2009a, County, Texas ( ) (Fig. 1A). Dromomeron Nesbittof the astragalus 2011) (Fig. in early2C). dinosaurs lacks a crest, and the gregorii from specimens Sarigülfrom the 2016 Cooper Canyon Formation and DISCUSSION and unnamed lagerpetids are known primarily Prior to 2003, our understanding of the early evolu- County and Howard County, Texas, respectively (Nesbitt tion of the dinosaurian lineage was restricted largely to etColorado al. 2009a City, Martz Formation 2007 ,of 2008 the ,Dockum Small and Group Martz in Garza2013, early-branching taxa such as Lagerpeton chanarensis, Lessner et al. 2018) (Fig. 1A, C). The age of these units Lewisuchus admixtus, and Marasuchus lilloensis from the is not well-constrained outside of vertebrate biostra- Middle Triassic Chañares Formation of Argentina (Fig. tigraphy, but the horizon containing lagerpetids in the 1A, B), and early theropod dinosaurs such as Herrerasau- Cooper Canyon Formation (MOTT 3839) may be roughly rus ischigualastensis and Eoraptor lunensis Sereno et al. 1993 from the Middle to Upper Triassic Formation (~212 Ma, early Revueltian), and that con- Ischigualasto FormationReig, of Argentina1963 and coelophysoids tainingequivalent D. gregorii to the Petrified in the lower Forest part Member of the Colorado of the Chinle City Formation (MOTT 2000/TMM 31100) may be roughly Africa (i.e., Raath 1977, Colbert 1989, Sereno and Novas equivalent to the Mesa Redondo Member of the Chinle 1992from Upper, Sereno Triassic and Arcucci rocks in 1994a North, America1994b). andA revolution southern Martz 2007, 2008, Ra- in dinosauromorph anatomy and systematics began mezani et al. 2011, , , with the publication of Silesaurus opolensis FormationLessner et al.(~225 2018 Ma,). A Otischalkian, single distal end of a left femur of D. ( ), and subsequent discover- gregorii was referredSarigül from 2016 the PlaceriasMartz and Quarry Parker (Fig. 2017 1A, ies and reinterpreted taxa all around the worldDzik, 2003have redistributedPiechowski and character Dzik 2010 states along the avemetatarsalian evolutionary tree (e.g., , Ferigolo and Langer in1C, age UCMP (Nesbitt 25815, et al.loc. 2009a A269), Ramezani in northeastern et al. 2014 Arizona,, Martz is , Irmis et al. 2007, Nesbitt et al. 2009a, 2009b, now known to be). approximately Until now, that 219 specimen Ma, or wasAdamanian, the only Nesbitt et al. 2010, KammererEzcurra 2006 et al. 2011, Cabreira et 2006 , , Nesbitt et al. 2017). Thus, andThe Parker oldest 2017 dated lagerpetids are found in the Chañares Lagerpetidae, the earliest group of dinosaur relatives that lagerpetid known from the Chinle FormationMariscano ofet Arizona.al. 2015, al.were 2016 onceMartinez restricted et toal. the2016 Middle Triassic of Argentina, Ezcurra et al. 2017) or the Santa Maria Formation of Bra- was recognized as a clade that lived alongside silesaurid zilFormation (~233 Ma. in ArgentinaLanger et al. (~236 2018 Ma,), and old forms are found dinosauriforms, theropods, and sauropodomorphs in in the Colorado City Formation and Cooper Canyon For- the Late Triassic of North American and South America. - dates (Langer et al. 2013, Lessner et al., 2018, Müller et al. mation2018). Lagerpetids in Texas, but were those present units lack throughout reliable radiometric most of the (FigLagerpetids 1A). Dromomeron are known romeri from was nearly originally every major named terres from Late Triassic and persisted well into the Norian (Langer trial Upper Triassic rock unit in western North America et al. 2013, Müller et al. 2018). Until now, the youngest of the Chinle Formation in the Hayden Quarry at Ghost lagerpetids associated with independent radiometric Ranch,specimens New collected Mexico, whichfrom the is approximatelyPetrified Forest 212 Member Ma in dates were those from the Hayden Quarry (~212 Ma) age (Revueltian, Irmis et al. 2007, 2011, and the slightly higher Snyder Quarry within the Chinle 2017). An additional astragalocalcaneum is present from Formation in New Mexico (Irmis et al. 2011, Langer et al. the nearby Snyder Quarry (NMMNH P-35379),Martz and which Parker is 2013). However, the MNA specimen described here from slightly higher stratigraphically relative to the Hayden Quarry but well below the Coelophysis Quarry within the ‘siltstone member’ (Nesbitt et al. 2009a, Whiteside et al. locality MNA 795 is from the Owl Rock Member, which is 2015). A lagerpetid referred to D. romeri is present in the hasassociated been dated with aat U-Pb approximately date from the 208 uppermost Ma (Ramezani Petrified et Chinle Formation of the Eagle Basin in western Colorado al.Forest 2011 Member) (Fig. 1A). at Thus,Petrified the Forestspecimen National here referred Park, which to D. (Small and Martz 2013), which has been correlated with romeri older than 208 million years and is currently the youngest from the Owl Rock Member at Ward Terrace is no the Petrified Forest Member and is Revueltian in age PALEOBIOS, VOLUME 35, DECEMBER 2018

6 radioisotopically-dated non-dinosaur dinosauromorph, Triassic of Texas, USA and its implications for early dinosaur as other young records (i.e., the Eagle Basin lagerpetid evolution. Acta Palaeontologica Polonica https:// and Dromomeron gigas) await more precise age control. doi.org/10.4202/app.00372.2017 Bell, C.J., J.J. Head, and J.I. Mead. 2004. Synopsis 63: 129–145. of the [ herpe- At present, only more derived lagerpetids (D. romeri ] in and D. gregorii (ed.). Biodiversity Response to Climate Change in the Middle tofaunaPleistocene: from The Porcupine Porcupine Cave. Cave Pp. Fauna117–126 from Colorado.A.D. Barnosky Uni- Carnian record) areof Lagerpetidae identified from includes the Upper Lagerpeton Triassic [https://doi. chanarensisrocks in Arizona,, Ixalerpeton New Mexico, polesinensis and ,Texas and PVSJ (Fig. 883, 1). Theand org/10.1525/california/9780520240827.003.0011 Bell,versity C.J., J.A.of California Gauthier, Press, and G.S.Berkeley, Bever. California. 2010. Covert biases, is restricted to Gondwana, whereas the Norian record ] only includes species within the genus Dromomeron from American Quaternary Herpetofaunal Stability Hypothesis. Qua- Laurasia (except for D. gigas, which is from northwest- ternarycircularity, International and apomorphies: a[ critical look at the North ern Argentina). It is unclear whether this temporal and quaint.2009.08.009 geographic segregation is real or artifactual, as much of 217:30–36. https://doi.org/10.1016/j. reptiles. Zoological Journal] of the Linnean Society Benton,[ M.J. 1985. Classification and phylogeny of the diapsid - Benton, M.J. 1999. Scleromochlus taylori and the origin 84:97–164. of dino- tionthe first in Brazil half orof thethe Carnian Norian ofis Northmissing America. in Argentina, Regardless, and saurshttps://doi.org/10.1111/j.1096-3642.1985.tb01796.x and pterosaurs. Philosophical Transactions of the ]Royal thislagerpetids specimen are of not D. yet romeri known from the Caturrita Forma Society of London Series B Biological Sciences of the Chinle Formation on the Navajo Nation extends [https://doi.org/10.1098/rstb.1999.0489 the stratigraphic range of Lagerpetidae from the Owl at Rock or above Member the Cabreira, S.F., Kellner, A.W.A., Dias-da-Silva, S.,354:1423–1446. da Silva, L.R., Norian-Rhaetian boundary, and it may extend from the Bronzati, M., de Almeida Marsola, J.C., Müller,] R.T., de Souza Bittencourt, J., Batista, B.J.A., Raugust, T. and R. Carrilho. - chean. At least in North America, lagerpetid dinosauro- reveals dinosaur ancestral anatomy and diet. Current Biology morphslatest Otischalkian occurred alongside or earliest theropod Adamanian dinosaurs into the a mereApa 2016. A unique Late Triassic dinosauromorph assemblage seven million years prior to the end-Triassic extinction. Camp, C.L. 1930. A study of the phytosaurs with description of new26:3090–3095. material from [https://doi.org/10.1016/j.cub.2016.09.040 western North America. Memoirs of the] ACKNOWLEDGEMENTS University of California Case, E.C. 1928. A cotylosaur from the Upper Triassic of western Texas. Journal of the10:1–161. Washington Academy of Sciences Association, the Museum of Northern Arizona, and the 18:177–178. DorisThis O. work and wasSamuel funded P. Welles by the Fund Petrified at the Forest University Museum of Chatterjee, S. 1985. Postosuchus, a new thecodontian reptile from the Triassic of Texas and the origin of tyrannosaurs. Philo- Smith (PEFO), Dave and Janet Gillette (MNA), Pat Holroyd sophical Transactions of the Royal Society of London, Series B, (UCMP),California and Museum Kristen of MacKenzie Paleontology. (DMNH) Thank for you access to Matt to Biological Sciences [https://doi.org/10.1098/ rstb.1985.0092 specimens in their collections. The MNA specimen from Colbert, E.H. 1947. Studies 309:395–460. of the phytosaurs Machaeroprosopus the Navajo Nation was collected under a permit from and Rutiodon. Bulletin] of the American Museum of Natural His- the Navajo Nation Minerals Department. Any persons tory [ wishing to conduct geologic investigations on the Navajo Colbert, E.H. 1989. The Triassic dinosaur Coelophysis. Museum of Northern 88:53–96. Arizona http://hdl.handle.net/2246/395 Bulletin ] Cope, E.D. 1875. Report on the geology of that part of northwest- Nation must first apply for and receive a permit from, 57:1–160. Pp. 981–1017 in G.M. Wheeler (ed.). Annual Report Upon the P.O. Box 1910, Window Rock, AZ 86515 and telephone Geographicalern New Mexico Explorations examined West during of the the One field Hundredth season of Merid 1874.- number (928) 871-6587. This manuscript was greatly improved by suggestions and comments by Bill Parker, New Mexico, Wyoming and Montana. United States Printing viewsJeffrey presented Martz and Sterlingherein are Nesbitt. those This of the is Petrified author and Forest do ian in California, Nevada, Nebraska, Utah, Arizona, Colorado, notNational represent Park thePaleontological views of the U.S.Contribution Federal Government. No. 60. The AvesOffice, of Washington, North America. D.C. Transactions of the American Philosophi- Cope,cal E.D.Society 1869. 14:1–252. Synopsis [https://doi.org/10.2307/1005355 of the extinct Batrachia, Reptilia and LITERATURE CITED Cope, E.D. 1887. The dinosaurian genus Coelurus. American Natu- La- ralist ] gerpeton chanarensis Romer (Thecodontia, Largerpetonidae - Arcucci,nov.) delA.B. Tríassic 1986. Nuevos medio materialesde La Rioja, y Argentina. reinterpretacion Ameghiniana de ities from 21:367-369. the early Late Triassic of Poland. Journal of Vertebrate 23:233–242. Dzik,Paleontology J. 2003. A beaked herbivorous[ archosaur with dinosaur affin Baron, M.G., and M. Williams. 2018. 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