Doña Ana Mountains in a shale bed ~ 15 m possesses: (1) a hemicylindrical calcaneal Tooth Hill near San Jon yielded a microverte- below the top of the Shalem Colony Formation condyle for the fibula; (2) a flexed tibial facet on brate fauna composed of redfieldiid and semi- and only a few meters below fusulinacean pack- astragalus; (3) a single articulation between onotid fish, indeterminate reptiles, several mor- stones of the Pseudoschwagerina zone. This astragalus and calcaneum; and (4) single para- photypes of archosauriform teeth, small phy- assemblage occurs in the upper part of a 2.7-m- median osteoderm per vertebra. Further, it is tosaurs, and possible ornithischians. thick shale interval, which is overlain by a 0.4- assignable to a clade containing derived cruro- Chondrichthyans are conspicuously absent. m-thick, fossiliferous limestone bed containing tarsans on the basis of an advanced “crocodile- Many of the archosauriform tooth morphotypes brachiopods and gastropods. This assemblage normal” tarsus. are known from much older (Adamanian) taxa, consists of brachiopods (Squamaria moorei? and thus are not age-diagnostic. The microverte- Muir-Wood & Cooper, Derbyia sp., Composita brates do, however, provide some insight into cracens Cooper & Grant, Crurithyris tumibilis the small-bodied fauna of the Redonda Forma- Cooper & Grant), bivalves (Septimyalina burmai A SKULL OF THE PHYTOSAUR PSEUDO- tion, which appears to have been dominated by Newell), nautiloids (Pseudorthoceratidae), gas- PALATUS FROM THE UPPER TRIASSIC small archosauriforms. The putative ornithischi- tropods (Tychonia inexpectata Kues, Euphemites (LATE CARNIAN) SANTA ROSA FORMA- an teeth, while fragmentary, constitute the only sp.) and bryozoans (Protoretepora sp.). The fauna TION OF CENTRAL NEW MEXICO, Adrian record of ornithischian body fossils in the is dominated by S. moorei? and bryozoans. The P. Hunt, [email protected], and Redonda Formation. The diversity from this S. moorei? are in various states of preservation, Spencer G. Lucas, New Mexico Museum of preliminary sample hints at a large microverte- including specimens more complete than previ- Natural History and Science, 1801 Mountain brate fauna that remains largely undiscovered, ously reported from the Robledo Mountains. Road NW, Albuquerque, New Mexico 87104 and should spur additional interest in the The Shalem Colony Formation assemblage is microvertebrate record of the Redonda Forma- indicative of shallow marine, shelf waters with Pseudopalatus is a common genus of Late Triassic tion. Indeed, the Redonda Formation is the most enough energy to move large brachiopod shells. phytosaur that has biochronologic significance; fossiliferous stratigraphic unit of latest Triassic The macroinvertebrate assemblage from the its an index taxon for the early Norian Revuelt- age in western North America, and is clearly the Shalem Colony Formation is less diverse than, ian lvf. A skull from the late Carnian of central key to understanding latest Triassic vertebrate but similar in composition and relative abun- New Mexico is the first occurrence of this genus evolution. dances to, the more extensive assemblages before the Norian. known from the stratigraphically higher Roble- NMMNH P-25745 is from NMMNH locality do Mountains Formation in the Robledo Moun- 3108, which is the type locality of Typothorax tains. This suggests chronofaunal stability of the antiquum. This locality is in the Tres Lagunas COPROLITES AND COLOLITES FROM THE invertebrate macrofauna during much of Hueco LATE TRIASSIC THEROPOD DINOSAUR, Member of the Santa Rosa Formation in Santa Fe COELOPHYSIS BAURI Group deposition on the Early Permian Robledo County. NMMNH P-25745 is a partial skull rep- , WHITAKER shelf of southern New Mexico. resented by the region posterior to the mid point QUARRY, RIO ARRIBA COUNTY, NEW of the orbits. The anterior margin slopes anteri- MEXICO, Larry F. Rinehart, rinehartl@nmmnh orly such that the lateral temporal fenestrae are .state.nm.us, Adrian P. Hunt, Spencer G. Lucas, preserved on both sides. The skull is slightly and Andrew B. Heckert, New Mexico Museum THE POSTCRANIAL SKELETON OF of Natural History and Science, 1801 Moun- REVUELTOSAURUS CALLENDERI flattened dorsoventrally. NMMNH P-25745 can be assigned to Pseudopalatus on the basis of: pos- tain Road NW, Albuquerque, New Mexico (ARCHOSAURIA: CRUROTARSI) FROM sessing a moderately wide postorbital squamos- 87104 THE UPPER TRIASSIC BULL CANYON al bar, supratemporal fenestrae that are short FORMATION OF EAST-CENTRAL NEW and narrow in dorsal view with narrow anterior New Mexico Museum of Natural History’s MEXICO, Adrian P. Hunt, ahunt@nmmnh margins, and a parietal-supraoccipital complex Whitaker (Coelophysis) Quarry block (C-8-82) .state.nm.us, and Spencer G. Lucas, New Mexi- that has an inverted U shape. from the Apachean-aged Rock Point Formation co Museum of Natural History and Science, This is the first occurrence of Pseudopalatus of the Chinle Group contains abundant fossils of 1801 Mountain Road NW, Albuquerque, New before the beginning of the Norian. This pro- Coelophysis bauri, non-dinosaurian tetrapods, Mexico 87104 vides evidence for a refinement of the robust fish, and invertebrates. At least three specimens biochronology of the Late Triassic based on land of C. bauri have fossil fecal material directly In 1986 field parties collected an extensive verte- vertebrate biochrons. associated with articulated skeletal material brate fauna from the Late Triassic (Revueltian These specimens apparently include material lvf: early Norian) Bull Canyon Formation of retained within the posterior intestine (cololites) east-central New Mexico. These included teeth as well as evacuated material (coprolites). The assigned to Revueltosaurus callenderi, which was THE MICROVERTEBRATE FAUNA OF cololites and coprolites occur between the ischia considered to represent an ?ornithischian SHARK TOOTH HILL, REDONDA FOR- and the proximal caudal vertebrae, and postero- dinosaur. Other associated remains included a MATION (LATE TRIASSIC:APACHEAN), ventral to this area. Most of the coprolite materi- partial skeleton (NMMNH P-16932) and other QUAY COUNTY, NEW MEXICO, Andrew B. al is formless and was apparently somewhat specimens of an undescribed armored cruro- Heckert, [email protected], Spen- mixed with still-wet mud and silt at or near the tarsan. Preparation of dentulous cranial frag- cer G. Lucas, and Adrian P. Hunt, New Mexico time of death. In P-44801, a small amount of ments of NMMNH P-16932 has shown that this Museum of Natural History and Science, 1801 coprolite material contains sparse bone frag- animal is Revueltosaurus and that it is not an Mountain Road NW, Albuquerque, New Mex- ments. The cololite and/or coprolite material ornithischian dinosaur. ico 87104 associated with P-42352 is enigmatic; it consists Revueltosaurus is a crurotarsan distinguished of small bone fragments in a densely packed by wide rectangular paramedian osteoderms The Upper Triassic Redonda Formation in east- matrix of small (~1 mm long by ~0.1 mm diam- with an irregular pattern of deep pits and no lat- central New Mexico consists of fluvial, lacus- eter), rod-shaped material. The coprolitic mate- eral osteoderms, a wide tarsus that has a small trine, and lacustrine-margin strata deposited rial associated with P-44552 is copious, formless, astragalar medial process and corresponding during latest Triassic time. The macrovertebrate and rich in bone fragments. Bone fragments pre- medial calcaneal concavity, and teeth that are body fossil record of the formation is under- pared from this material include a distal ulna, an remarkably convergent on ornithischians. studied, but known to include the redfieldiids ulnare, and partial phalanges that apparently Many partial osteoderms and one complete Cionichthys and Synorichthys stewarti, the semi- pertain to juvenile Coelophysis and provide fur- osteoderm are in the collection. The complete onotids Semionotus and cf. Hemicalypterus, the ther evidence of cannibalism in this dinosaur. osteoderm is rectangular and is 64 mm long, 33 lungfish Arganodus, an indeterminate coela- Additional material appears to include wrist mm wide, and 5 mm thick. The dorsal surface is canth, the temnospondyl Apachesaurus gregorii, a bones, long-bone and rib fragments, and thin covered by an irregular pattern of deep, round- large cynodont, the archosauromorph Van- sheets similar to skull or pelvic bone. Few exam- ed pits. The medial end of the osteoderm is cleavea, the phytosaur Redondasaurus, the ples of close associations between fecal material thickened. The osteoderm thins at its lateral and aetosaur Redondasuchus, a giant sphenosuchian, and vertebrate fossils are known, and this is a anterior margins. A smooth lapet runs along the and possible theropod dinosaurs. The microver- unique occurrence for a dinosaur. anterior margin and broadens near the lateral tebrate fauna is essentially unstudied, but is margin. known to include a broadly similar fish fauna. This taxon represents a crurotarsan because it Screenwashing for microvertebrates at Shark

May 2005, Volume 27, Number 2 NEW MEXICO GEOLOGY 53