Here we establish the stratigraphic and geographic provenance of the "Belodon" buceros Cope. The holotype, originally collected by David Baldwin in 1881, is an incomplete phytosaur skull discovered near "Huerfano Camp" in north-central New Mexico. This skull is the first phytosaur skull described from the American West, and its precise provenance has never been established. Baldwin's use of the term Huerfano Camp may refer to Orphan Mesa, an isolated butte just south of Arroyo Seco. Fossils collected by Baldwin, and our subsequent collections from Orphan Mesa, are from a fossiliferous interval high in the Petrified Formation of the Chinle Group. These strata yield a tetrapod fauna including the aetosaur Typothorax coccinarum and the phytosaur Pseudopalatus, both index taxa of the Revueltian (early-mid Norian) land-vertebrate faunachron. "Belodon" buceros is correctly referred to Pseudopalatus buceros (Cope) and is an index taxon of the Revueltian land-vertebrate faunachron

Heckert, Andrew B.

NC DOCKS at Appalachian State University

English

The University of North Carolina at Greensboro

Heckert, A.B., and Lucas, S.G., eds., 2002, Upper Triassic Stratigraphy and Paleontology. New Mexico Museum of Natural History and Science Bulletin No. 21. 189 THE TYPE LOCALITY OF BELODON BUCEROS COPE, 1881, A PHYTOSAUR (ARCHOSAURIA: PARASUCHIDAE) FROM THE UPPER TRIASSIC OF NORTH-CENTRAL NEW MEXICO SPENCER G. LUCAS, ANDREW B. HECKERT, KATE E. ZEIGLER and ADRIAN P. HUNT lNew Mexico Museum of Natural History, 1801 Mountain Road NW, Albuquerque, NM 87104-1375 Abstract-Here we establish the stratigraphic and geographic provenance of the "Belodon" buceros Cope. The holotype, originally collected by David Baldwin in 1881, is an incomplete phytosaur skull discov-ered near "Huerfano Camp" in north-central New Mexico. This skull is the first phytosaur skull de-scribed from the American West, and its precise provenance has never been established. Baldwin's use of the term Huerfano Camp may refer to Orphan Mesa, an isolated butte just south of Arroyo Seco. Fossils collected by Baldwin, and our subsequent collections from Orphan Mesa, are from a fossilifer-ous interval high in the Petrified Formation of the Chinle Group. These strata yield a tetrapod fauna including the aetosaur Typothorax coccinarum and the phytosaur Pseudopalatus, both index taxa of the Revueltian (early-mid Norian) land-vertebrate faunachron. "Belodon" buceros is correctly referred to Pseudopalatus buceros (Cope) and is an index taxon of the Revueltian land-vertebrate faunachron. Keywords: phytosaur, Belodon, Pseudopalatus, Revueltian INTRODUCTION In the Fall of 1874, Edward Drinker Cope (1840-1897) trav-eled through parts of north-central New Mexico and the San Juan Basin, collecting vertebrate fossils of Late Triassic, Late Cretaceous and early Eocene age (Simpson, 1951). The Triassic vertebrates he collected were the first fossils of that age collected in the Ameri-can West, even though Marcou (1858) had earlier posited the pres-ence of Triassic strata in New Mexico. More specifically, Cope collected Triassic vertebrate fossils in an area just north of Gallina (Fig. 1) that was relocated by Lucas and Hunt (1992). Cope's col-lections included the holotype of the aetosaur Typothorax coccinarum, described by Cope (1875). Subsequently, Cope's hired fossil collector, David Baldwin, obtained Triassic vertebrate fossils in north-central New Mexico. Among the fossils Baldwin sent Cope is an incomplete phytosaur skull, the holotype of Belodon buceros Cope, 1881 (Figs. 2-3). This skull is the first phytosaur skull described from the American West, IJ~ ; '. ·~7q,.s..,;~ ... ~ I------'~I ii\ \ I Cerro Blanco II \ b Triassic strata 20km FIGURE 1. Map of part of north-central New Mexico showing distribution of Upper Triassic strata of the Chinle Group (after Dane and Bachman, 1965) and locations mentioned in the text. As = Arroyo Seco; Cq = Canjilon quarry; G = Gallina; GR = Ghost Ranch; OM = Orphan Mesa; Sq = Snyder quarry. and its exact provenance has never been ascertained. Here, we establish the geographic and stratigraphic provenance of the ho-lotype of Belodon buceros and discuss its taxonomic position and biostratigraphic significance. Abbreviations: AMNH American Museum of Natural History, New York; NMMNH New Mexico Museum of Natural History and Science, Albuquerque; UCMP = University of Cali-fornia Museum of Paleontology, Berkeley; USNM = Smithsonian Institution, Washington D.C. PROVENANCE When naming Belodon buceros, Cope (1881, p. 922) merely noted it as "in my New Mexican collections" and provided no precise locality data. Huene (1915, p. 490-492, fig. 11) redescribed and illustrated the holotype of Belodon buceros (Fig. 3), reassign-ing it to Phytosaurus, but provided no locality data other than New Mexico. More recent authors have also only stated that the fossil is from New Mexico or have ventured to state that it is from Rio Arriba County (e.g., Hunt and Lucas, 1989, 1993a; Lucas and Hunt, 1992; Hunt, 1993, 1994; Long and Murry, 1995). Ironically, the records that establish the precise provenance of the holotype of Belodon buceros have always been with the fos-sil, and in the AMNH archives. Indeed, the holotype skull, AMNH 2318, has a packing slip written by David Baldwin that indicates it was "Sack 5. Box 5/1 shipped to Cope on 21 June 1881. The ship-ping manifest written by Baldwin, in AMNH archives, states the following for fossils shipped that date: Sack 5. Box 5. Large reptile head, southeastern side of Rincon, Huerfano Camp, Arroyo Seco, end of snout or jaw dug out showing some front teeth, June 1881. The large reptile head clearly refers to the holotype skull, and the locality, Arroyo Seco, is one discussed at length by Sullivan et aL (1996). Thus, the Arroyo Seco drainage is near Ghost Ranch in Rio Arriba County (Fig. I), and Baldwin evidently collected some of the syntypes and referred specimens of the dinosaur Coelophysis here in 1881. Furthermore, Baldwin's use of the term 190 -A-B c ---0 4cm FIGURE 2. AMNH 2318, holotype skull of the phytosaur Belodon buceros Cope, 1881, from the Petrified Forest Formation in the Chama basin, northern New Mexico. A-B, Lateral views; C, Occipital view; D, Dorsal aspect of posterior end of skulL "Huerfano Camp" may refer to Orphan Mesa (huerfano is Span-ish for orphan), an isolated butte just south of Arroyo Seco (Sullivan et aL, 1996, fig. 2). Baldwin's stratigraphic observations, also in the AMNH archives, indicate that his" Arroyo Seco" lo-calities are approximately 400 ft (-123 m) below the 1/ gypsum stra-tum," known now as the Middle Jurassic Todilto Formation (Sullivan et aL, 1996). Throughout the Chama basin, rocks 100+ m below the Todilto Formation are part of the Petrified Forest Formation (Lucas and Hunt, 1992; Hunt and Lucas, 1993a; Sullivan et aL, 1996). Fossils collected by Baldwin (especially some of the syntypes of the dinosaur Coelophysis), and subsequent NMMNH collections from the Orphan Mesa area, are from a fossiliferous interval high in the Petrified Formation of the Chinle Group (Fig. 4; Sullivan et aL, 1996; Sullivan and Lucas, 1999). It is thus highly likely that this is the stratigraphic provenance of AMNH 2318, the holotype of Belodon buceros. Indeed, the preservation of the specimen is siIni-lar to that of other vertebrate fossils from this horizon. Further-more, other fossils of "Belodon" buceros occur at this horizon, and only at this horizon (see below). In fact, a skull of "Belodon" buceros has just been collected near Orphan Mesa at this horizon by a field party from Ghost Ranch (A. Downs, oral commun., 2002). Therefore, we conclude that David Baldwin certainly col-lected the holotype of Belodon buceros in the Arroyo Seco drainage near Orphan Mesa in Rio Arriba County, New Mexico (in, or near, T24N, R4E). The fossil almost certainly was collected from a hori-zon in the upper part of the Petrified Forest Formation of the Chinle Group. This is in part because the bulk of the accessible strata in this region are in the upper half of the Petrified Forest Formation and because we and others have recovered additional FIGURE 3. Illustrations of the holotype skull, AMNH 2318, of Belodon buceros, from Huene (1915). fossils from this interval and had little success collecting above or below it (Sullivan et al., 1996; Sullivan and Lucas, 1999). REDESCRIPTION AND TAXONOMY AMNH 2318 (Figs. 2-3) is a poorly preserved skull of a Pseu-dopalatus-grade phytosaur. We assign this skull to Pseudopalatus (= Arribasuchus) because the supratemporal fenestrae are narrow and slit-like in dorsal view, the squamosals are generally rod-shaped with hook-like processes, the occipital region is u-shaped, and the external nares are at approximately the same level as the skull roof. The skull is approximately 745 mm long, but is missing the anterior end of the snout. The specimen is 277 mm wide across the quadrates and 150 mm high at the orbits. The ventral aspect of the specimen is in poor condition, but its morphology is simi-lar to other Pseudopalatus-grade phytosaurs. The rostral crest is 130 mm tall and 270 mm long, and because this crest is very ro-bust, we consider this skull to be a male morphotype of Pseudopalatus (Zeigler et al., 2002, 2003). Cope (1881) did not illustrate the holotype of his Belodon buceros. McGregor (1906, pl. 9) was the first to illustrate the speci-men, also referring the specimen to Belodon buceros. Jaekel (1910) erected the genus Metarhinus for this species, but this name was preoccupied by a Paleogene mammal (a brontothere). Mehl (1915) placed the species in the genus Lophoprosopus. Huene (1915, fig. 11) illustrated this specimen and placed buceros in the genus Phytosaurus, whereas Mehl et al. (1916) placed this species in his new genus Machaeroprosopus. Subsequently, Gregory (1962a,b) placed the species in Rutiodon, and Ballew (1989) in Pseudopalatus. Hunt and Lucas (1993a) and Hunt (1994) considered buceros to be a valid species of Nicrosaurus. Historically, workers have distinguished Nicrosaurus from Pseudopalatus principally by the presence of external nares elevated above the level of the skull roof in the latter (e.g., Ballew, 1989; Hunt, 1994; Long and Murry, 1995; Hungerbiihler and Hunt, 2000). Entrada Sandstone (Middle Jurassic) c c ~ &~ .:.:; E o ... o 0 a::u.. Canjilon quarry 191 Key l>==3 Repti!ebones Conglomerate ~ Mudstone c==J Sandstone, crossbedded c==J Sandstone, massive 10 blocky Sandstone-pebbly/coarse Sandslone,ripp!e'!amiMled ~Sandstone&cong!omerate.crossbedde Pedogenic? carbonale horizofl FIGURE 4. Measured stratigraphic sections of Upper Triassic strata in the Chama basin showing the distribution of Pseudopalatus buceros (modified from Lucas and Hunt, 1992; Sullivan et aL, 1996). We note here that this feature is often difficult to interpret as phytosaur skulls are often distorted and crushed, altering the apparent profile of the skull. Our assignment of B. buceros to Pseudopalatus is based on the derived features of Pseudopalatus listed above that are evident in AMNH 2318. Note also that we do not accept Long and Murry's (1995) synonymy of Redondasaurus with Pseudopalatus. Redondasaurus is a distinct phytosaur known from younger strata in Oklahoma, New Mexico, and Utah, including the Ghost Ranch Coelophysis quarry in the Rock Point Formation, approximately 60 m above the Pseudopalatus occurrences in the Chama basin (Hunt and Lucas, 1993a,b; Lucas et al., 1997a,b; Heckert et al., 2001). BIOSTRATIGRAPHY Fossils of Pseudopalatus buceros occur in the Chama basin at three localities (Fig. 1): 1. The type locality of P. buceros, discussed above. 2. The Canjilon phytosaur quarry north of Ghost Ranch (Lawler, 1974; Long et al., 1989; Hunt and Lucas, 1993a; Long and Murry, 1995 Zeigler et al., 2003). 3. The Snyder quarry, near the Canjilon quarry (Zeigler et al.,2002). All three of these occurrences are at essentially the same stratigraphic level: uppermost part of the Petrified Forest Forma-tion of the Chinle Group (Fig. 4). This level is of Revueltian (Norian) age, as it yields fossils of Pseudopalatus and the aetosaur Typothorax coccinarum (Lucas, 1998). P. buceros thus has an ex-tremely restricted stratigraphic range in the Chama basin indica-tive of Revueltian time. ACKNOWLEDGMENTS E.S. Gaffney and M. Norell made access to AMNH fossils and archives possible. J. Estep garnered corroborating informa-tion at the Academy of Natural Sciences in Philadelphia with the help of T. Daeschler. 192 REFERENCES Ballew, K L., 1989, A phylogenetic analysis of Phytosauria from the Late Triassic of the western United States; in Lucas, S. G., and Hunt, A P., eds., Dawn of the age of dinosaurs in the American Southwest: Albu-querque, New Mexico Museum of Natural History, p. 309-339. Cope, E. c., 1875, Report on the geology of that part of northwestern New Mexico examined during the field-season of 1874: Annual report upon the geographical explorations west of the 100th meridian [Wheeler Survey], Appendix LL, Annual Report Chief of Engineers for 1875, p. 61-97 of separate issue, 981-1017 of full report. Cope, E. D., 1881, Belodon in New Mexico: American Naturalist, v. 15, p. 922-923. Dane, C. H., and Bachman, G. 0., 1965, Geologic map of New Mexico: U.S. Geological Survey, scale 1:500,000. Gregory, J. T., 1962a, The genera of phytosaurs: American Journal of Sci-ence, v. 260, p. 652-690. Gregory,J. T., 1962b, The relationships of the American phytosaur Rutiodon: American Museum Novitates, v. 2095, p. 1-22. Heckert, A B., Lucas, S. G., Hunt, A P., and Harris, J. D., 2001, A giant phytosaur (Reptilia: Archosauria) skull from the Redonda Formation (Upper Triassic: Apachean) of east-central New Mexico: New Mexico Geological Society, Guidebook 52, p. 171-178. Huene, F. V., 1915, On reptiles of the New Mexican Triassic in the Cope collection: Bulletin of the American Museum of Natural History, v. 34, p.485-507. Hungerbiihler, A, and Hunt, A P., 2000, Two new phytosaur species (Archosauria, Crurotarsi) from the Upper Triassic of southwest Ger-many: Neues Jahrbuch fUr Geologie und Palaontologie Monatshefte, v. 2000, p. 467-484. Hunt, A. P., 1993, Taxonomy of phytosaurs (Reptilia:Archosauria) from the Canjilon quarry, Petrified Forest Formation, north-central New Mexico: New Mexico Museum of Natural History and Science Bulle-tin 3, p. G13. Hunt, A P., 1994, Vertebrate paleontology and biostratigraphy of the Bull Canyon Formation (Chinle Group, Upper Triassic), east-central New Mexico with revisions of the families Metoposauridae (Amphibia: Temnospondyli) and Parasuchidae (Reptilia: Archosauria) [PhD. dis-sertation]: Albuquerque, University of New Mexico, 404 p. Hunt, A P. and Lucas, S. G., 1989, Late Triassic vertebrate localities in New Mexico; in Lucas, S. G., and Hunt, A P., eds., Dawn of the age of dinosaurs in the American Southwest: Albuquerque, New Mexico Museum of Natural History, p. 72-101. Hunt, A P., and Lucas, S. G., 1993a, Stratigraphy and vertebrate paleon-tology of the Chinle Group (Upper Triassic), Chama Basin, north-cen-tral New Mexico: New Mexico Museum of Natural History and Sci-ence, Bulletin 2, p. 49-90. Hunt, A P., and Lucas, S. G., 1993b, A new phytosaur (Reptilia: Archo-sauria) genus from the uppermost Triassic of the western United States and its biochronological significance: New Mexico Museum of Natu-ral History and Science, Bulletin 3, p. 193-196. Jaekel, 0., 1910, Uber einen neuen Belodonten aus dem Buntsandstein von Berburg: Sitzungsberichte Gesellschaft naturforschender Freunde zu Berlin, v. 5, p. 197-229. Lawler, D. A, 1974, Osteological variation in the phytosaur Rutiodon tenuis from Ghost Ranch, New Mexico [M.A thesis]: Berkeley, University of California, 137 p. Long, R. A, and Murry, P. A, 1995, Late Triassic (Carnian and Norian) tetrapods from the southwestern United States: New Mexico Museum of Natural History and Science, Bulletin 4, 254 p. Long, R. A, Lucas, S. G., Hunt, A P., and McCrea, R. T., 1989, Charles Camp: collecting Late Triassic vertebrates in the American Southwest during the 1920's and 1930's; in Lucas, S. G., and Hunt, A P., eds., Dawn of the Age of Dinosaurs in the American Southwest: Albuquer-que, New Mexico Museum of Natural History, p. 65-71. Lucas, S. G., 1998, Global Triassic tetrapod biostratigraphy and biochron-ology: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 143, p. 347-384. Lucas, S. 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Zeigler, KE., Lucas, S.G., and Heckert, AB., 2002, A phytosaur skull from the Upper Triassic Snyder quarry (Petrified Forest Formation, Chinle Group) of north-central New Mexico: New Mexico Museum of Natu-ral History and Science, Bulletin 21, p. 171-177. Zeigler, K E., Lucas, S. G. and Heckert, A B., 2003, Variation in the Late Triassic Canjilon quarry (Upper Chinle Group, New Mexico) phytosaur skulls: A case for sexual dimorphism in phytosaurs: PaIaontologische Zeitschrift (in press). 

The type locality of Belodon buceros Cope, 1881, a phytosaur (Archosauria: Parasuchidae) from the Upper Triassic of north-central New Mexico

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The type locality of Belodon buceros Cope, 1881, a phytosaur (Archosauria: Parasuchidae) from the Upper Triassic of north-central New Mexico

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