The Campanian Terlingua Local Fauna, with a Summary of Other Vertebrates from the Aguja Formation, Trans-Pecos Texas Author(S): Timothy Rowe, Richard L

Home , Baculites, Cimolestes, El Gallo Formation, Judith Schiebout, Onchopristis, Sclerorhynchidae

The Campanian Terlingua Local Fauna, with a Summary of Other Vertebrates from the Aguja Formation, Trans-Pecos Texas Author(s): Timothy Rowe, Richard L. Cifelli, Thomas M. Lehman, Anne Weil Source: Journal of Vertebrate Paleontology, Vol. 12, No. 4 (Dec. 15, 1992), pp. 472-493 Published by: The Society of Vertebrate Paleontology Stable URL: http://www.jstor.org/stable/4523473 Accessed: 12/04/2010 20:53

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474 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992

SN SW NE

------(non-marine)- upper shale mbr.------

V58/TMM 43057 (approx.) Terlingua Creek sandstone mbr. S- MNH (approx.)-- -..,58/TMM43057 RattlesnakeMt. sandstone mbr. McKinneySprings tongue of PenFm. o

----lower shale mbr. basal sandstonembr -

PEN FORMATION (marine)

TEXAS

OMNHV58/ TMM 43057

FIGURE 2. Stratigraphicrelationships of the Pen and Aguja formationsthrough Big Bend National Park, includinginformal units designated by Lehman (1985a, 1989). The shaded area of the map, includingthe approximatelocation of the microsite, is BrewsterCounty, Texas. centrate contained abundant residual carbon, the sam- continuous lignite that contains twigs and branches of ples were subsequently separated with the heavy liquid carbonized wood, leaf material, amber, and angio- zinc bromide (e.g., Reynolds, 1983), adjusted to a spe- sperm seeds. The microvertebrate-bearing bed is 13 to cific gravity of between 2.3 and 2.4, prior to picking 18 cm thick, and consists of discontinuous stringers of concentrate under a dissecting microscope. Processing fine (granule to small pebble) conglomerate separated of samples collected in 1988 yielded approximately 17 by thin lenses of fine sandstone and clayey siltstone. mammal specimens per 100 kg of original rock matrix, The conglomerate stringers are the principal source of a high level of productivity by Cretaceous standards. the microvertebrate fossils. Clasts in the conglomerate range up to 2 cm in diameter, although most are less than 1 cm. The clasts THE TERLINGUA LOCAL FAUNA LOCALITY comprise clay balls, wood, coal, amber, coprolites, and abundant, disarticulated mi- The microvertebrate locality (OMNH V58; TMM crovertebrate bones and teeth. The site also produces 43057) lies approximately 8 km NNE of Study Butte, isolated larger bones, most notably isolated limb ele- Brewster County, Texas (Figs. 1, 2). Detailed locality ments and vertebrae of a hadrosaur, and shell frag- information is on file at the Oklahoma Museum of ments of a huge trionychid turtle. Many bones in all Natural History and the Vertebrate Paleontology and size classes are broken. Some bones exhibit varying Radiocarbon Laboratory of the University of Texas. degrees of abrasion and rounded edges indicative of The locality is stratigraphically within the lower part transport before burial. Branches of carbonized wood of the upper shale member of the Aguja Formation, lacking preferred orientation are common at the top within several meters of the top of the underlying ma- of the bone-producing horizon. Most of this wood con- rine Terlingua Creek sandstone member (Fig. 2). The tains mud filled Teredolites (shipworm) borings. bone-producing bed rests upon a distinctive, laterally The bone-bearing deposit ranges up to 10 m wide, ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 475 and represents deposition in a shallow channel with a Slaughter (1972), only some of the Aguja archosaurs sluggish current. Downcutting into the underlying lig- were subsequently described (Coombs, 1978; Davies, nite was not observed at the locality itself, but it does 1983; Lehman, 1982, 1985a, 1989). Much of the work occur in similar, adjacent deposits at the same strati- carried out by Louisiana State University in the Aguja graphic level. Overlying the channel are overbank de- Formation was summarized in a dissertation (Stand- posits of clay-rich siltstone, typical of Lehman's (1985a) hardt, 1986), but apart from a faunal summary tabu- coastal floodplain facies. lated by Standhardt (in Langston et al., 1989), none of Both the geology and faunal composition (see below) this work is published. indicate a predominantly terrestrial source for the sed- iment and fossils at the site. there preserved However, THE TERLINGUA LOCAL FAUNA is also evidence of significant marine influence on the faunal composition, which is not surprising given the Below is a list of taxa comprising the Terlingua local stratigraphic proximity of marine sediments. Teredoli- fauna, and a brief discussion of its major components. tes indicates a brackish or saline environment, and We adopted a conservative approach in taxon iden- relatively direct communication to an open marine tification, taking names only to the levels permitted by environment. There are eight sharks in the fauna (see material recovered from this locality. For example, below) that further support this interpretation, in that although isolated ceratopsian teeth recovered from the all eight taxa have also been recovered from marine locality probably represent Chasmosaurus mariscalen- sediments. Lepisosteids and amiids, also well repre- sis, named from material collected elsewhere in the sented in the fauna, are primarily freshwater taxa al- Aguja (Lehman, 1982, 1989, 1990a), we prefer to as- though both have high salinity tolerances and are con- sign them to Ceratopsidae until more specifically diag- sistent with an estuarine environment (Hoese and nostic material is identified in collections from the site. Moore, 1977; Bryant, 1987). We also note that many identifications are based more on phenetic resemblances than on the presence of de- monstrable because VERTEBRATE COLLECTIONS FROM THE synapomorphies, phylogenetic at levels are not available for most AGUJA FORMATION analyses alpha yet of the taxa at issue. Thus, many of the names used Significant collections from the Aguja Formation below could be thought of as "form taxa" rather than were first made between 1938 and 1940 under the monophyletic entities. The major exception to this is direction of William Strain (University of Texas at El in our discussion of the squamates, which benefits from Paso), who directed a Works Progress Administration the phylogenetic hypotheses developed by Estes paleontological project in west Texas. At nearly the (1983b), Estes et al. (1988), Gauthier (1982) and Gau- same time, collections were made by Barnum Brown thier et al. (1988). Taxa marked with an asterisk (*) for the American Museum of Natural History, and by represent first occurrences for the Aguja Formation. William McAnulty, Donald Savage, and Wann Lang- Voucher specimens are listed in Appendix 1 for all ston, Jr., for the University of Oklahoma (for details taxa discussed below. see Lehman, 1985a, 1989; Langston et al., 1989; Da- vies and Lehman, 1989). From the 1960s through the CHONDRICHTHYES 1980s, Dr. Langston assembled a large collection of Euselachii Aguja vertebrates for the Vertebrate Paleontology Lab- Hybodontoidea oratory of the University of Texas, an effort carried on Hybodontidae by some of his students (e.g., Davies, 1983; Lehman, *Hybodus sp. 1982, 1985a, 1989). Most of this work focused on the Hybodontidae, indet. megafauna, but a recent collaborative effort by the Uni- Polyacrodontidae versity of Oklahoma and University of Texas collected Lissodus (=Lonchidion) selachos a large sample of Aguja microvertebrates that signifi- Lamniformes cantly increased the documented diversity of Aguja Mitsukurinidae vertebrates (Cifelli and Rowe, 1990). Judith Schiebout Scapanorhynchys sp. and Barbara Standhardt of Louisiana State University Batomorphii made additional microvertebrate collections in the Rajiformes 1970s and early 1980s. The net result of these 50 years Sclerorhynchidae of collecting in the Aguja is more than 1,000 cataloged Onchopristis dunklei specimens representing roughly 70 vertebrate species. *Ischyrhiza avonicola Although Aguja vertebrates have been known for Rajiformes incertae sedis more than half a century, few Aguja taxa have received Squatirhina americana comprehensive treatment in the literature. The first Ptychotrygon sp. descriptions of these materials were by Brown (1942), Batomorphii indet. followed by Colbert and Bird (1954) on the giant croc- Myliobatiformes odilian Deinosuchus (=Phobosuchus) riograndensis. Dasyatidae Apart from the description of a shark by McNulty and Chondrichthyes indet. 476 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992

ACTINOPTERYGII Maniraptora Lepisosteidae Troodontinae Amiidae *cf. Troodon Teleostei Velociraptorinae *Phyllodontidae *cf. Saurornitholestes Teleostei indet. Dromaeosaurinae LISSAMPHIBIA *cf. Dromaeosaurus Urodela Maniraptora incertae sedis Prosirenidae *cf. Ricardoestesia Albanerpeton sp. MAMMALIA Scapherpetontidae Multituberculata Urodela indet. *Neoplagiaulacidae *Anura Cimolomyidae CHELONIA *Cimolomys clarki Cryptodira Meniscoessus Trionychidae *Meniscoessus sp. nov. "Aspideretes" *Cimolodontidae Baenidae *Cimolodon cf. electus "Baena" *cf. Cimolodon Chelonia indet. Multituberculata incertae sedis SQUAMATA gen. et sp. nov. *Anguimorpha Marsupialia *Anguidae *"Peradectidae" *Glyptosaurinae *Alphadon cf. A. wilsoni * Odaxosaurus sp. *Alphadon sp. nov. * Proxestops sp. *Turgidodon sp. Glyptosaurinae indet. Pediomyidae Anguidae indet. *Pediomys cf. P. krejcii *Xenosauridae ?Eutheria *Restes sp. *Gallolestes sp. Varanoidea Mammalia, incertae sedis ("metatherian-eutherian *Necrosauridae grade" or "Tribotheria" ) *Scincomorpha *sp. nov. *Scincidae *Sauriscus sp. *Scincidae sp. nov. A. Chondrichthyes *Teiidae For convenience, we use the nomenclature of Cap- *Teiidae sp. nov. B petta (1987) for chondrichthyans, though we note that *Serpentes the monophyly of most of the categories recognized Squamata indet. below is not demonstrated. spe- *Squamata sp. nov. X Eight chondrichthyan cies were identified in the Terlingua local fauna *Squamata sp. nov. Y (Fig. 3). Five are batoids, represented by abundant isolated CROCODYLIA teeth, occasional denticles, and rostral spine fragments. Mesosuchia These include two sclerorhynchid rajiforms, Oncho- Goniopholidae pristis dunklei McNulty and Slaughter (1962) and Is- Eusuchia chyrhiza avonicola Estes (1964), and two rajiforms of Deinosuchus riograndensis uncertain affinities, Squatirhina americana Estes (1964) *PTEROSAURIA and what may be a new species of Ptychotrygon (Fig. DINOSAURIA 3). The occurrence of Onchopristis dunklei is a range Ornithischia extension, being previously known no higher in strati- Ankylosauria graphic position than the Cenomanian Woodbine For- Ornithopoda mation (McNulty and Slaughter, 1962; Slaughter and Hadrosauridae Steiner, 1968). Cappetta (1987) noted with skepticism Ceratopsia reports of Onchopristis dunklei from the Upper Cre- Ceratopsidae taceous (Campanian or Maastrichtian) of New Zealand Saurischia and India. Theropoda The fifth batoid is an indeterminate dasyatid, rep- Carnosauria resented by a single, large square tooth. Several frag- Tyrannosauridae mentary teeth in our collection may represent addi-

478 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992 species, of which the prosirenian Albanerpeton sp. Anguimorpha -As in other Late Cretaceous and ear- (=Prodesmodon copei, in part, of Estes, 1964; see Estes, ly Tertiary faunas from the Western Interior, the most 1981) is the most abundant, being represented by more common squamate elements are isolated osteoderms than 100 maxilla and dentary fragments. Albanerpeton of glyptosaurine anguids. Also preserved are jaw frag- is easily recognized by its non-pedicillate teeth and by ments and isolated teeth with the characteristic square a complex, interdigitating joint at the dentary sym- profile of Odaxosaurus sp. (=Pancelosaurus piger, in physis (Estes, 1981). A wide size range of these ele- part, of Meszoely, 1970; =Peltosaurus piger of Estes, ments is present in the large sample of jaws from Ter- 1964; see Gauthier, 1982). These specimens are among lingua. The largest specimens are more than twice the the oldest known glyptosaurines; other Campanian oc- size of the smallest specimens. Whether this is the currences are reported in the correlative Fruitland, Ju- manifestation of ontogenetic or taxonomic diversity is dith River, and "Mesaverde" formations (Estes, 1964, not yet known. A second salamander, probably a sca- 1983a; Sullivan, 1987), and from the eastern seaboard pherpetonid, is represented by isolated vertebral ele- (Denton et al., 1991). Glyptosaurines are also well ments. This may be the taxon that Standhardt (1986) known from early Tertiary deposits of Wyoming and identified from elsewhere in the Aguja as Scapherpeton Montana (Meszoely, 1970; Gauthier, 1982; Sullivan tectum. Anurans, rare elements in the fauna, are rep- 1982, 1987); the group became extinct near the end of resented by jaw fragments, distal ends of humeri, and the Oligocene. Scutes referable to the glyptosaurine partial ilia. The number and identity of the anuran Proxestops (see Gauthier, 1982) are also present in the taxa remain to be determined. Terlingua local fauna, though comparatively rare. Albanerpeton, which ranges from the Middle Juras- An additional anguid is represented by three jaw sic to the Middle Miocene (Estes, 1981), is uninform- fragments. The teeth in these specimens are strongly ative regarding the age of the Terlingua local fauna. recurved or bowed posteriorly, and the crowns are stri- Without more specific identification, none of the lis- ated lingually but not laterally. The crowns are bi- samphibians is helpful in this respect. cusped, with a small anterior lobe separated from the larger posterior lobe by a groove on both the lingual Chelonia and lateral surfaces. Specimens such as these were com- monly assigned to Gerrhonotinae in earlier literature Seven turtle taxa are reported from the Aguja For- mation (Table 1), but only two were identified in the (e.g., Armstrong-Ziegler, 1978, 1980; Sullivan, 1981). However, Good that this tooth Terlingua local fauna. A large trionychid referable to (1988) recently argued form is plesiomorphic for and that the form genus "Aspideretes" is represented by nu- Anguidae, high in the other characters merous large shell fragments. The rear half of a skull variability among anguids preserved in the material leave the and possibly other shell fragments indicate the pres- fragmentary Terlingua specimens to but not to a more ence of a large baenid, which Hutchison (pers. comm.) assignable Anguidae, specific level. assigns to the form genus "Baena." We also recovered several isolated turtle dentaries that are from much In addition to the three anguids, two other angui- are rare. One smaller individuals and that represent two or morphis present, though comparatively may pos- is a a maxilla with teeth that three taxa. Although turtles provided xenosaur, represented by sibly significant have a weak anterior that is set off from the stratigraphic resolution elsewhere in Late Cretaceous cusp large posterior cusp by a weak on the lateral surface. and Early Tertiary terrestrial sediments (e.g., Hutchi- groove son and are as too We refer this specimen to Restes (=Exostinus; Gau- Archibald, 1986), they yet poorly The second known in the Terlingua local fauna to be informative thier, 1982) sp. non-anguid anguimorph is referred to Necrosauridae. It is known in this regard. provisionally from a few jaw fragments with pleurodont teeth that are and that have the character- Squamata laterally compressed istic infolded enamel of varanoids. All teeth are broken Until now, squamates were poorly represented in above their infolded bases. Several osteoderms in our southerly Late Cretaceous faunas of North America collection may also represent this taxon. Both xeno- (Estes, 1983a, b). Apart from a passing mention of saurs and necrosaurids are reported from Maastrich- indeterminate mosasaurs in marine facies (Maxwell et tian deposits elsewhere (Estes, 1983a; Sullivan, 1987); al., 1967), no squamates were previously reported in their occurrence in the Terlingua local fauna is the first the Aguja Formation. Only four species are known in report from Campanian sediments. Older angui- the Fruitland Formation (Armstrong-Ziegler, 1978, morphs were described by Winkler et al. (1990) from 1980; Sullivan, 1981), and only one is reported for the several localities in Early Cretaceous (Commanchean) "El Gallo" Formation (Estes, 1983a). The Terlingua sediments of Texas. None of the Terlingua angui- local fauna fills this important geographic gap with a morphs is sufficiently constrained temporally to offer diverse assemblage of squamates (Fig. 4). All of the useful information on the age of the fauna. material at this site is fragmentary, consisting of iso- Scincomorpha- Three scincomorphs are now known lated cranial elements, jaw fragments, isolated teeth, in the Terlingua local fauna. Two are referable to Scin- and isolated scutes. Nevertheless, the material permits cidae (Fig. 4), extending the distribution of Scincidae recognition of 10 taxa. into the Campanian for the first time in North Amer- ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 479

_...

~5~t I s~r.E

FIGURE 4. Scincids of the Terlingua local fauna. A-D, Scincidae sp. nov. (TMM 43057-286), right dentary: A, lateral view; B, lingual view; C, D, details of posterior dentary tooth crowns in occlusal and lingual views. E-G, Sauriscus sp. (OMNH 25347), maxilla: E, lateral view; F, medial view; G, details of tooth crowns in labial view.

ica. As Estes (1983a) and Sullivan (1987) argued, ear- mids, iguanines, and amphisbaenians, evidently aris- lier reports of Campanian scincids (Russell, 1975, 1982) ing independently in each case (Estes et al., 1988; were in error. The most common squamate in the Ter- Ethridge and de Queiroz, 1988). The teeth in the Ter- lingua local fauna, next to the glyptosaurines, is a large lingua material are similar to the large, bulbous teeth scincid with a highly distinctive dentition, which we of the extant scincid, Tiligua scincoides. However, the refer to informally as species A. It is represented by a Terlingua taxon is seemingly unique in that the teeth number ofjaw fragments and isolated teeth. A peculiar occluded to produce on each tooth a pair of crescentic feature of the dentary is that the Meckelian groove is wear facets, separated by a transverse ridge. Teeth lying enclosed to form a tube by fusion of the dentary along near the front of the mouth are compressed antero- its ventral edge, from very near the symphysis poste- posteriorly and are considerably smaller than the more riorly to near the level of the coronoid. The splenial is posterior, 'molariform' teeth. They also developed wear absent from the tooth-bearing portion of the mandible. facets. In their functional arrangement and degree of The most comparable dentaries are in other scincids, heterodonty, these teeth are reminiscent of the massive although similar features also occur in dibamids, py- dentitions of the Late Cretaceous teiid Peneteius (Estes, gopodids, gekkonids, xantusiids, some gymnophthal- 1969), and to a lesser degree the polyglyphanodontines 480 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992

TABLE 1. Uncritical tabulation of vertebrates reported from the Aguja Formation.

Taxon References Chondrichthyes Hybodus sp. This paper Lissodus selachos This paper; Standhardt, 1986 Cretorectolobus olsoni Standhardt, 1986 Odontaspis sp. Langston et al., 1989 Anomotodon angustidens Lehman, 1985a Scapanorhynchus texanus Lehman, 1985a Scapanorhynchus raphidon Langston et al., 1989 Scapanorhynchus sp. This paper; Russell, 1988 Squalicorax kaupi Lehman, 1985a Squalicorax sp. Russell, 1988 Onchopristis dunklei This paper Onchopristis sp. Davies, 1983; Russell, 1988 Ischyrhiza avonicola This paper Ischyrhiza mira Lehman, 1985a Squatirhina americana This paper; Standhardt, 1986 Ptychotrygon agujaensis McNulty and Slaughter, 1972; Langston et al., 1989; Russell, 1988 Phychotrygon sp. This paper; Lehman, 1985a; Standhardt, 1986 Myledaphus bipartitus Standhardt, 1986 Dasyatidae sp. This paper Psuedocorax (=Corax) sp. Wixson, 1963 Isurus sp. Wixson, 1963 Lamna appendiculata Langston et al., 1989 Cretolamna sp. Russell, 1988 Actinopterygii Melvius thomasi Boreske, 1974 cf. Melvius Bryant, 1987; Russell, 1988 Amiidae This paper; Lehman, 1985a; Standhardt, 1986 Lepisosteidae This paper; Davies, 1983; Lehman, 1985a; Standhardt, 1986 Lepisosteus sp. Russell, 1988 Atractosteus sp. Standhardt, 1986 Lissamphibia Albanerpeton This paper Albanerpeton nexosus Standhardt, 1986 Scapherpetontidae indet. This paper Scapherpeton tectum Standhardt, 1986 Anura sp. This paper Chelonia Adocus sp. Lehman, 1985a; Langston et al., 1989 "Aspideretes" This paper; Lehman, 1985a; Langston et al., 1989 "Baena" cf. B. nodosa Lehman, 1985a; Langston et al., 1989 "Baena" This paper cf. Basilemys sp. Davies, 1983; Lehman, 1985a; Langston et al., 1989 Compsemys victa Standhardt, 1986; Langston et al., 1989 ? Taphrosphys sp. Lehman, 1985a; Langston et al., 1989 Thescelus cf. T. insiliens Lehman, 1985a; Langston et al., 1989 Thescelus sp. Lawson, 1972; Langston et al., 1989 Squamata Odaxosaurus sp. This paper Proxestops sp. This paper Restes sp. This paper Necrosauridae This paper Scincidae, sp. A This paper Sauriscus sp. This paper Teiidae, sp. B This paper Squamata indet., sp. X This paper Squamata indet., sp. Y This paper Serpentes This paper ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 481

TABLE 1. (Continued)

Taxon References Mosasauridae Maxwell et al., 1967; Lehman, 1985a; Standhardt, 1986; Langston et al., 1989 Crocodylia Goniopholidae This paper Goniopholus cf. kirtlandicus Lehman, 1985a Deinosuchus riograndensis This paper; Colbert and Bird, 1954 cf. Leidyosuchus Langston et al., 1989 cf. Brachychampsa Standhardt, 1986; Langston et al., 1989 Pterosauria Pterosauria This paper Dinosauria Kristosaurus cf. K. navajovius Lawson, 1972; Davies, 1983 (= ?Gryposaurus) Weishampel and Homer, 1990 Hadrosauridae This paper; Weishampel and Homer, 1990; Weishampel, 1990 Lambeosaurinae indet. Davies, 1983; Weishampel, 1990 Hypsilophodontidae Davies, 1983 Stegoceras sp. Lehman, 1985a; Weishampel, 1990 Panoplosaurus sp. Coombs, 1978; Carpenter, 1990 cf. Euoplocephalus Standhardt, 1986 Nodosaurinae Lehman, 1985a Edmontonia cf. rugosidens Coombs and Maryanska, 1990; Weishampel, 1990 cf. Ankylosauridae Standhardt, 1986 Chasmosaurus mariscalensis Lehman, 1989; Weishampel, 1990 Ceratopsidae This paper; Standhardt, 1986 Tyrannosauridae This paper; Lehman, 1985a; Weishampel, 1990 Ornithomimidae Davies, 1983; Weishampel, 1990 Paronychodon lacustris Standhardt, 1986; Langston et al., 1989 Troodon sp. Standhardt, 1986 cf. Troodon This paper cf. Saurornithoides This paper cf. Dromaeosaurus This paper cf. Ricardoestesia This paper Mammalia "tribothere" new sp. This paper Ptilodontoidea Standhardt, 1986 Eucosmodontidae Standhardt, 1986 Cimolomyidae, new sp. Standhardt, 1986 Meniscoessus sp. Standhardt, 1986 Meniscoessus, sp. nov. This paper Cimolodon cf. electus This paper cf. Cimolodon This paper Cimolomys clarki This paper Neoplagiaulacidae This paper Multituberculata incertae sedis, sp. nov. This paper Alphadon ef. A. wilsoni This paper Alphadon cf. A. marshi Standhardt, 1986 Alphadon sp. This paper Turgidodon sp. This paper Pediomys cf. P. krejcii This paper Gallolestes sp. This paper

(Estes, 1983a), both of which are unknown in the Ter- ent from previously described species in having crowns lingua local fauna. that are only incipiently divided into three weakly de- The second scincid is referable to Sauriscus sp., and fined lobes; in other species the crowns are markedly is represented in the fauna by several broken jaws. Its tricusped (e.g., Estes, 1964). Both of the Terlingua scin- tooth crowns bear weak striations lingually and marked cids represent new taxa. striations laterally. The teeth appear somewhat differ- In addition to the two scincids, at least one teiid 482 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992

occurs in the Terlingua local fauna, which we refer to opholid. The Terlingua goniopholid may prove to be informally as species B. It is represented by broken jaw Goniopholis cf. G. kirtlandicus, which is known else- fragments and isolated teeth in which there is a widely where in the Aguja (Lehman, 1985a), but available open Meckelian fossa (indicating a large splenial), ex- material is too fragmentary to permit more specific tensive deposition of cementum around the bases of identification. Standhardt (in Langston et al., 1989) the teeth, and a well developed subdental shelf and referred isolated teeth from the Aguja to Leidyosuchus sulcus dentalis (Estes et al., 1988). The Terlingua taxon and Brachychampsa, but we found no record of either differs from other Cretaceous teiids in having teeth that in the Terlingua local fauna. We also note that Dr. are weakly tricusped. The crowns are smooth laterally, Langston (pers. comm.) doubts that either taxon can weakly striated lingually, and faintly defined anterior be diagnosed by the fragmentary material currently and posterior cusps are set off from the main crown known from the Aguja. by a shallow lingual groove. Teiids have an extensive Dinosauria: Ornithischia - Three ornithischians oc- Cretaceous record in North America. Winkler et al. cur in the Terlingua local fauna, the most common of (1990) tentatively referred material to Teiidae from which is an indeterminate hadrosaur represented by the Commanchean (Early Cretaceous) of Texas, and isolated teeth, ossified tendons, isolated limb elements, there is a diversity of named teiids from the Late Cre- and vertebrae. This material includes very young and taceous. Chamops segnis and Leptochamops denticu- adult individuals. Both Kritosaurus (=?Gryposaurus of latus are known from the correlative Fruitland For- Weishampel and Homer, 1990) cf. K. navajovius (Law- mation (Armstrong-Ziegler, 1978, 1980; Estes, 1983a; son, 1972; Davies, 1983) and an indeterminate lam- Sullivan, 1987). Kequin and Fox (1991) recently de- beosaurine (Davies, 1983; Weishampel and Homer, scribed five new teiid species in the correlative Oldman 1990) are reported from elsewhere in the Aguja. Cer- Formation, and they list eight additional Lancian teiids atopsians are also present, but in less relative abun- from North America. Like the anguimorphs, the Ter- dance than the hadrosaurs. Chasmosaurus mariscalen- lingua scincomorphs are currently of little use in refin- sis (Lehman, 1989), described from material discovered ing the age of the Terlingua local fauna. elsewhere in the Aguja, is in all likelihood the Terlingua Serpentes - A snake is present in the Terlingua local ceratopsian, but diagnostic material has yet to be re- fauna. One tiny jaw fragment preserves one recurved covered from the locality. The third ornithischian re- tooth that is set into a shallow socket, and on either corded is an ankylosaur, known only from osteoderms. side is an additional shallow socket. The tooth has a None of the ornithischian remains from the Terlingua circular base, is strongly recurved, and lacks serrations. locality offers any refinement of the age of the Terlingua Armstrong-Ziegler (1978, 1980) described a snake, local fauna, although specimens from elsewhere in the which she identified as an aniliid, from the Campanian Aguja support our Judithian assignment (see below). Fruitland-Kirtland formations. The specimen was lat- Theropoda - Theropods are present, although only isolated teeth and a few isolated and er identified as a boid (Rage, 1984; Estes and Baiez, bones bone frag- 1985; Sullivan, 1987). Apart from its being a snake, ments have yet been recovered. We followed the cri- little can be said of the identity of the Terlingua spec- teria described by Currie et al. (1990) in identifying imen at present. isolated teeth from the Judith River Formation. The Squamata indet. - Two additional lizards, which we Terlingua local fauna includes at least one large tyran- refer to informally as species X and species Y, are, at nosaurid, and four smaller maniraptorans (Fig. 5) which present, indeterminate members of Squamata. In the we provisionally refer to cf. Dromaeosaurus, cf. Saur- former, the teeth are solidly ankylosed to the jaws and ornitholestes, cf. Ricardoestesia, and cf. Troodon. their crowns are blunt and rounded. The inframan- Standhardt (1986) identified Paronychodon lacustris dibular septum was evidently long and relatively slen- in the upper Aguja, which may be what we refer to as der. Species Y has distinctive teeth that have smooth, cf. Saurornitholestes (see Currie et al., 1990). Several unicusped crowns, and there is a very narrow dental other teeth do not easily fit into any of those categories gutter. Few other details of morphology are available but generally resemble teeth of the small, bird-like for either taxon at present. theropods. The general similarity of the Judith River theropod assemblage to that of the Terlingua local fauna may Archosauria offer further corroboration of a Judithian assignment for the latter. As Currie et al. (1990) point out, how- Crocodylia--At least two crocodilians occur in the ever, small theropod teeth are common in most Late Terlingua local fauna. These are Deinosuchus (=Pho- Cretaceous faunas, and the distributions of these re- bosuchus) riograndensis and an indeterminate goni- cently recognized taxa are not yet well documented.

FIGURE 5. Small theropods of the Terlingualocal fauna. A-C, Cf. Saurornitholestestooth (TMM 43057-316): A, lateral and lingual views; B, detail of tip; C, detail of serrationsalong posterior edge. D-F, Cf. Ricardoestesiatooth (TMM 43057- 313): D, lateral and lingual views; E, detail of tip; F, detail of serrationsalong posterioredge. G-I, Cf. Dromaeosaurustooth

484 JOURNALOF VERTEBRATEPALEONTOLOGY, VOL. 12, NO. 4, 1992

FIGURE 6. Mammals of the Terlingualocal fauna. A, Tribotheria,incertae sedis, right lower molar (OMNH 22789). B, Alphadonsp., left upper molar (OMNH 22721). C, Alphadoncf. A. wilsoni, left upper molar (OMNH 22724). D, Gallolestes sp. left lower molar (OMNH 22788). E, F, Cimolodoncf. electus, left fourth lower premolar(OMNH 25042): E, lingual;F, labial. G, Cimolomys clarki, upper right first molar in occlusal view (OMNH 25014). A, B, C, D, and G in occlusal view; scale is 1 mm.

Pterosaurs- Several crushed, incomplete bones in- in size, anteriorly placed, but not so lingual as is gen- dicate the presence of pterosaurs in the Terlingua local erally seen in marsupials (Clemens, 1979). The cristid fauna, although specimens now in hand are too frag- obliqua attaches anteriorly to the base of the trigonid mentary for more specific identification. in a median position; a distal metacristid is lacking. The hypoconulid is in a median position, not shifted as is true of Mammalia lingually generally marsupials (Clemens, 1979; Clemens and Lillegraven, 1986; Cifelli and Ea- Order and Family Uncertain, gen. and sp. indet.-- ton, 1987). A labial postcingulid, also characteristic of A presumablynew taxon is representedby severallow- early marsupials but seen in some Cretaceous eutheri- er molars. These teeth (Fig. 6) bear fully developed, ans as well (Cifelli, 1990b), is lacking. tricuspid, basined talonids, and thus belonged to a tri- The affinities of this taxon are puzzling. Differences bosphenic therian in the sense of Crompton (1971). in height and width of the trigonid and talonid are less Beyond this, the affinities of the species are uncertain. pronounced than in presumably primitive Tribosphe- Distinctive marsupial or eutherian characters are lack- nida such as Kermackia texana (cf. Butler, 1978). The ing, and for convenience we refer to the taxon infor- lack of a distal metacristid is also a derived condition mally as a therian of "metatherian-eutherian grade" within Tribosphenida (Fox, 1975), perhaps suggesting (Patterson, 1956; Kielan-Jaworowska et al., 1979) or a relationship to certain "advanced" Theria of meta- "tribothere" (Clemens and Lillegraven, 1986), though therian-eutherian grade, marsupials, and eutherians we recognize that neither term refers to a monophy- (Cifelli, 1990e). However, the unreduced, anteriorly letic unit. The species is small, with teeth slightly small- placed paraconid is unlike that typical of Cretaceous er than those of Alphadon wilsoni Lillegraven, 1969. Eutheria. Likewise, the median position of the para- The positions of the referred teeth are unknown. All conid, lack of a labial postcingulid, and lack of ento- specimens have rounded, posteriorly narrowing tal- conid to hypoconulid twinning differ from conditions onids, suggesting that they may be ultimate lower mo- seen in early presumed marsupials or marsupial-like lars, but this may simply be a characteristic of all lower taxa (Cifelli, 1990c, d). An unusual tribosphenic upper molars of the taxon. The trigonid is broadly open lin- molar, almost certainly too small for this species, is gually, with the paraconid, subequal to the metaconid tentatively referred below to Gallolestes. ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 485

Multituberculata - Multituberculates are by far the tiny second molars. These teeth closely resemble Me- most common mammals at the Terlingua locality, with sodma, Cimexomys, and Paracimexomys, but second more than 400 specimens recovered to date. The ma- molars alone do not permit discrimination among these jority of these are incisors and premolars, and many taxa. We refer them to an indeterminate position with- of the larger teeth are fragmented. With three excep- in Neoplagiaulacidae. tions, the specimens are isolated teeth. Marsupialia: "Peradectidae" - We follow the usage Meniscoessus is the most common multituberculate. of Reig et al. (1987) in referring generally primitive Nine lower fourth (ultimate) premolars are now re- Cretaceous marsupials to "Peradectidae," thereby per- covered, but none is intact. These show size and struc- mitting Didelphidae, formerly used for this purpose, tural diversity that suggest the possibility of more than to be diagnosed on the basis of presumed synapomor- one taxon, though the small sample size leaves doubt phy (Cifelli, 1990a, d). We acknowledge, however, that on this point. Complicating identification of this ma- this practice perpetuates, rather than eliminates, usage terial are upper and lower first molars, clearly referable of "wastebasket" taxa. Remains of peradectid mar- to Meniscoessus, but which do not show divergence supials are abundant in the assemblage, but sample like that of the premolars. The Terlingua specimens sizes are currently insufficient to identify or circum- most closely resemble M. major, but are smaller than scribe any species reliably. Present evidence suggests known specimens of that taxon. We refer to these as the presence of two small species, herein placed in Meniscoessus, sp. nov., elsewhere in this paper. Alphadon, and at least one large species, probably re- Cimolodon is known from four entire and several ferable to Turgidodon (genera as defined and diagnosed fragmentary lower fourth premolars. These are nearly by Cifelli, 1990a). identical in size and structure to those of C. electus Alphadon sp.--This taxon, the smaller of the two from the Milk River Formation (Fox, 1971). Specific Aguja species referred to Alphadon, is represented by identification of the Terlingua Cimolodon is compli- several upper molars (Fig. 6); lower molars have not cated, however, by the presence of upper fourth pre- been positively identified. Morphologically, this spe- molars that are also assignable to Cimolodon (Fig. 6). cies is typical of Alphadon. It is distinct in having small, In most aspects of morphology they more closely re- sharp cusps C and D on the stylar shelf and, especially, semble C. nitidus than C. electus, but they are smaller in being noticeably smaller than other known Creta- than any known specimens of C. nitidus. We provi- ceous marsupials. For example, the average antero- sionally refer to all of these teeth as Cimolodon cf. posterior length (A-P length as defined by Lillegraven, electus. 1969) for M2 is 1.39 mm; averages for M2 of other Also provisionally referred to Cimolodon are several small species are: Iqualadelphis lactea, 1.70; Alphadon molars showing an unusual, complex pattern of pitting wilsoni, 2.1; and A. attaragos, 1.83 (data from Cifelli, that creates reticulated ridges on the occlusal surfaces. 1990a and Lillegraven, 1969). Teeth of Essonodon also share this feature, but Essono- Alphadon cf. A. wilsoni--This species is the most don has a more regular pattern of occlusal pits and abundant therian in the fauna. It is closely comparable ridges, and the upper second molars have a much lower to Alphadon wilsoni Lillegraven, 1969, and especially length to width ratio than is seen in the Terlingua resembles that species in that stylar cusp C is well- material. Eaton (1987) described similar teeth from defined and conical (Fig. 6). However, the Aguja ma- the Kaiparowits plateau of southern Utah, arguing that, terial is slightly more than one standard deviation with the exception of the pitting, the teeth most closely smaller than Alphadon wilsoni (cf. Lillegraven, 1969: resemble Cimolodon. We follow Eaton's conclusions 36-37), suggesting that it may prove to be a distinct by provisionally referring to the Terlingua material as taxon as our sample improves. cf. Cimolodon. Turgididon sp.--A third peradectid taxon, currently Cimolomys clarki Sahni, 1972, is represented in the known only from molar fragments, indicates an un- Terlingua local fauna (Fig. 6) by two upper first molars, identified species of Turgidodon, identified by large size one of which is fragmentary. It is significant that C. and by robust, inflated tooth cusps and heavy wear clarki is known exclusively from Judithian faunas (Lil- (Cifelli, 1990a). It is approximately the size of the Ju- legraven and McKenna, 1986); this occurrence sup- dithian Turgidodon russelli and T. madseni, but is in- ports the more compelling marine invertebrate data sufficiently known to make detailed comparisons. (see below) which indicate the Terlingua local fauna is Pediomyidae: Pediomys cf. P. krejcii--One small of Judithian "age." fragment of an upper molar records a tribosphenic Two additional multituberculate taxa occur in the therian with a reduced anterior stylar shelf. Recogniz- Terlingua local fauna. One is based on two upper first ing the difficulties involved in interpreting the affinities molars that are small, with low length to width ratios, of such taxa (see Fox, 1987), we refer the species ten- and that have distinctive, square-based pyramidal tatively to Pediomys. The species is small, comparable cusps. These features indicate a new taxon endemic to in size to Lancian P. krejcii Clemens, 1966; as in that the Terlingua local fauna, but one whose more general species, cusp D is small and C is apparently lacking. affinities are uncertain. For the moment, we refer it to ?Eutheria incertae sedis: Gallolestes sp.- This small Multituberculata incertae cedis, sp. nov. species (average A-P length for lower molars = 1.44) The last multituberculate is based on a number of resembles Gallolestes pachymandibularis, from the 486 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992

Campanian "El Gallo Formation," Baja California entrant into the literature on Aguja vertebrate pale- (Lillegraven, 1972, 1976). The Aguja species is known ontology than as a verified tabulation of the Aguja by lower molars (Fig. 6); a poorly preserved upper biota. molar may belong to it, but cannot be assigned to G. pachymandibularis with confidence. As in G. pachy- DISCUSSION mandibularis, the entoconid is placed lingually and the Age of the Terlingua Local Fauna paraconid is low and placed well anterior and labial to the metaconid. In addition to its smaller size, the Aguja Because radiometric dates have not been reported species is distinct in having less robust molars, less from the Upper Cretaceous section in the Big Bend height differential between protoconid and metaconid, region, dating of these deposits rests entirely on cor- and a deeper labial ectoflexid dividing the trigonid and relation of the vertebrate and invertebrate faunas, and talonid. An upper molar lacking most of the enamel on limited paleomagnetic stratigraphy. The Big Bend possibly belongs to this species, based on size (upper region is uniquely situated between the Cretaceous molars of Gallolestes are otherwise unknown) and its Western Interior and Gulf Coast marine zoogeographic dissimilarity to other tribosphenic therians from the provinces, and allows correlation of the biostratigraph- fauna (i.e., it does not belong to a marsupial and ap- ic zonations developed for each province. Marine in- pears to be too small for the metatherian-eutherian vertebrates from the intergonguing Pen and Aguja for- grade taxon noted above). The stylar shelf, which ap- mations provide a lower limit on the age of the pears to have lacked cusps in the C to D positions, is Terlingua local fauna assemblage; continental verte- modestly developed, except that an enormous para- brates from the overlying Javelina Formation provide style is present, giving the tooth the appearance of an an upper limit. ultimate upper molar. The metacone is well-devel- The main body of the Pen Formation lies within the oped, a point of difference from ultimate upper molars lower Campanian Delawarella delawarensis zone, based of marsupials and certain Late Cretaceous eutherians, on the occurrence of this Gulf Coast and Tethyan zonal such as Cimolestes. The tooth most resembles ultimate ammonite, as well as Menabites belli, Submortoniceras upper molars of other Eutheria, such as Procerberus vanuxemi, S. mariscalense, and S. chicosense (Young, formicarum; however, it may be a penultimate molar 1963). The upper part of the Pen Formation may ex- of a more primitive taxon (cf. Fox, 1975). tend into the overlying Delawarella sabinalensis zone, The affinities of Gallolestes are problematic. Lille- based on a single occurrence of this ammonite (Young, graven (1976) referred the genus to Eutheria, but Clem- 1963). However, the most common ammonite in the ens (1980), more conservatively, considered it simply Pen Formation, and in the paralic basal sandstone as Theria incertae sedis (see also Clemens and Lille- member of the Aguja Formation, is Placenticeras syr- graven, 1986). More recently, Nessov (1985) returned tale, known elsewhere from the lower Campanian of Gallolestes to Eutheria, placing it in the otherwise Asi- both the Gulf Coast and the Western Interior. Placen- atic suborder Mixotheridia. However, the trigonid ticeras meeki also occurs in the Pen Formation, the configuration does not resemble that of any other Cre- McKinney Springs tongue of the Pen Formation, and taceous mammal, although the reduction of the para- all sandstone members of the Aguja Formation, but conid is suggestive of Eutheria. Evidence provided by this is a wide-ranging species known elsewhere from the Aguja materials is inconclusive; if the upper molar throughout the Campanian and Maastrichtian (e.g., is correctly referred and if it represents M3, there is Reeside, 1927). The lower Campanian Gulf Coast am- some suggestion of relationship to Late Cretaceous monite Parapuzosia paulsoni occurs in the Rattlesnake Eutheria. Mountain sandstone member of the Aguja Formation. In summary, the Terlingua mammals include at least Several fragments of Hoplitoplacenticeras sp. are now one strictly Judithian element, Cimolomys clarki (Fox, known from the Terlingua Creek sandstone and, more 1971; Lillegraven and McKenna, 1986), and the re- importantly, poorly preserved specimens of Baculites maining taxa are all consistent with a Judithian as- maclearni are known from all sandstone members of signment. the Aguja Formation. Baculites maclearni is a zonal index for the base of the upper Campanian in the West- SUMMARY OF AGUJA VERTEBRATES ern Interior (Kauffman, 1977), and is the highest ammonite zone recorded in the Aguja. Lillegraven and Table 1 is an uncritical listing of all taxa reported Ostresh (1990) recently placed the Aguja above the from the Aguja Formation by previous researchers (with Baculites gregoryensis zone (their Zone 16), whereas citations) and from the Terlingua local fauna. The Agu- the data available to us indicate it to lie no higher than ja Formation includes marine, terrestrial, and inter- the Baculites maclearni zone (zone 11). Collectively, mediate deposits. It appears to span a considerable the ammonites indicate that the Pen Formation and length of time, including most of the Campanian and the lower part of the Aguja Formation, up to and in- perhaps the early part of the Maastrichtian (see below). cluding the Terlingua Creek sandstone member, are This list mixes taxa that may have been separated by Campanian in age. The lower/upper Campanian several million years and that lived in different envi- boundary probably lies at or above the level of the ronments. Table 1 should thus be viewed more as an Rattlesnake Mountain sandstone member. ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 487

Gryphaeid, ostreid, and inoceramid bivalves pro- ern Interior, although its composition is considerably vide a useful supplement to the correlation based on different from the typical Judithian faunas upon which ammonite zonation. Exogyra ponderosa ponderosa is the Land Mammal "age" was established. It is also abundant in the main body of the Pen Formation and likely that the Aguja Formation as a whole records a in the lower part of the McKinney Springs tongue of considerable expanse of time, and that the Aguja sec- the Pen Formation. In the Gulf Coast, E. ponderosa tion lying stratigraphically above the Terlingua locality ponderosa is known from lower and upper Campanian may span Judithian through the beginning of Lancian strata, up to the zone of Hoplitoplacenticeras vari time. is also (Young, 1963). Exogyra ponderosa upatoiensis with Other Southern Late known from the main of the Pen it Relationship Cretaceous body Formation; Terrestrial Faunas is not known to occur elsewhere above the zone of Delawarella delawarensis (Young, 1963). E. ponderosa The Terlingua local fauna is not strictly comparable erraticostata also occurs throughout the Pen Forma- to any other known Cretaceous local fauna, though it tion, but it is a temporally wide-ranging subspecies. does include elements known elsewhere from the West- The oysters, Flemingostrea pratti and F. subspatulata, ern Interior. Comparison of the Aguja microvertebrate are abundant in the Rattlesnake Mountain sandstone locality with faunas of the Fruitland-Kirtland forma- member of the Aguja Formation, and also occur in the tions of the San Juan Basin are problematic, in part Terlingua Creek sandstone member. Flemingostrea because the age of the Fruitland-Kirtland formations pratti is known from upper Campanian, and F. sub- has been controversial, and in part because their fauna spatulata from upper Campanian and lower Maas- is different in many regards from the classic northern trichtian, strata of the Gulf and Atlantic coasts (Wol- faunas. Like the Aguja Formation, the Fruitland-Kirt- leben, 1977; Sohl and Christopher, 1983). The oyster land formations probably span a considerable expanse Crassostrea cusseta is locally abundant in the basal of time. Most recent authors concluded that the Fruit- sandstone and Rattlesnake Mountain sandstone mem- land-Kirtland faunas are of "Edmontonian" age (Lil- bers; this species is known elsewhere only from middle legraven and Ostresh, 1990; see also Clemens, 1973; Campanian strata of the Gulf Coast (Sohl and Kauff- Clemens et al., 1979; and Lillegraven and McKenna, man, 1964). Inoceramus vanuxemi, I. barabini, and I. 1986; Kequin and Fox, 1991), but data from ammonite oblongus occur abundantly in the McKinney Springs stratigraphy and radiometric dates suggest that the best- tongue of the Pen Formation, suggesting an early late known mammal faunas, those from the Hunter Wash Campanian age for these strata. Hence, oyster and ino- and Fossil Forest localities, are Judithian, even though ceramid faunas also indicate a Campanian age for the they do not resemble the typical northern Judithian Pen and for the lower, marine part of the Aguja for- assemblages. These localities lie along the southwest- mation, with the lower/upper Campanian boundary ern edge of the San Juan Basin, in the stratigraphically falling perhaps at the level of the Rattlesnake Mountain lowest part of the Fruitland-Kirtland Formations. Sandstone member. Overlying the localities is a well-dated ash bed that Continental Cretaceous strata above the Terlingua yields an age of 72 to 75 Ma (Brookins and Rigby, Creek sandstome member of the Aguja Formation must 1987), which is about the age of the Didymoceras chey- at present be correlated on the basis of their vertebrate ennense zone. The highest ammonite beneath the lo- faunas. The theropod and mammal assemblages in the calities is Baculites scotti, known from the underlying Terlingua local fauna suggest a Judithian assignment, Pictured Cliffs Sandstone. Hence, the Hunter Wash and all of the remaining Terlingua taxa are consistent and Fossil Forest mammal faunas are bracketed be- with this position. The dinosaurs Chasmosaurus, Kri- tween the B. scotti and D. cheyennense zones, which tosaurus, Panoplosaurus, and ?Stegoceras are known are equivalent in age to the Judithian faunas of Mon- by specimens from higher levels in the upper shale tana and Canada (e.g., Goodwin and Deino, 1989); member, and also suggest a Judithian or "Edmonton- stratigraphically higher parts of the Fruitland-Kirtland ian" age for these beds (Lehman, 1989). The overlying formations probably extend into the "Edmontonian" Javelina Formation bears dinosaurs (Alamosaurus, and perhaps also Lancian. These conclusions are fur- Torosaurus, Tyrannosaurus) and mammals considered ther supported by Flynn's (1986) comparison of the to be Lancian (middle to late Maastrichtian) in age Hunter Wash mammals with northern Late Cretaceous (Lawson, 1976; Standhardt, 1986; Lehman, 1990b). assemblages. Flynn noted that no Lancian species is Limited paleomagnetic stratigraphy suggests that the present in the Hunter Wash fauna, and that the latter's base of the Javelina Formation must lie at least as low closest resemblance is to the Pre-Lancian Judith River as polarity chron C30N (mid-Maastrichtian; see Stand- and Milk River assemblages that define the Judithian hardt, 1986; Lehman, 1990b). "age." In sum, the combined evidence now available sug- If our preliminary identifications of mammals bear gests that the Terlingua local fauna, which lies at the up under more detailed comparisons, the Terlingua base of the upper shale member of the Aguja Forma- and Hunter Wash/Fossil Forest local faunas share Al- tion, is late Campanian in age. This fauna appears to phadon cf. wilsoni and Cimolodon cf. electus (Flynn, be correlative with Judithian Land Mammal "age" 1986); the former taxon is also reported in the Fossil faunas known from more northerly parts of the West- Forest local fauna (Rigby and Wolberg, 1987). Both 488 JOURNAL OF VERTEBRATEPALEONTOLOGY, VOL. 12, NO. 4, 1992 taxa occur in northern faunas (Sahni, 1972; Fox 1971); at this time in the Western Interior Seaway (e.g., Sohl, their occurrence in the Terlingua local fauna is south- 1971; Kauffman, 1977, 1984; Nicholls and Russell, ern range extension. 1990). Apart from ceratopsians, which are different in the Among mammals, the ?eutherian Gallolestes is two faunas, the archosaurian components are not well known only in the two southern-most localities. The known in either case. Several ceratopsians are tenta- distinctive multituberculate that we refer to as cf. Cim- tively reported in older literature from the Fruitland- olodon, which is present in the Terlingua and Kaipa- Kirtland formations, but all identifiable specimens rowits faunas (Eaton 1987), has not been found any- recovered from the Hunter Wash-Fossil Forest strat- where north of the Kaiparowits Plateau. In this context, igraphic interval are referable to Pentaceratops stern- it is also notable that pediomyid marsupials are rare bergii (Rowe et al., 1981; Lehman, 1990a). Its close and stagodontids appear to be absent in the Terlingua relative, Chasmosaurus mariscalensis, is the only diag- fauna, as is the case with other southern faunas (e.g., nosable ceratopsian yet recognized in the Aguja (Leh- Clemens, 1973; Eaton and Cifelli, 1988). Further de- man, 1982, 1989, 1990a) and is probably the ceratop- marcating southern from northern faunas are endemic sian represented in the Terlingua local fauna. The multituberculate and marsupial species, which occur remaining vertebrates of the New Mexican faunas are in all of the southern faunas except the poorly known too poorly known to afford informative comparisons. "El Gallo." The best represented Late Cretaceous fauna from The Terlingua reptiles also show differences from the southern part of the Western Interior is that of the northern faunas. Four new, endemic squamate taxa Kaiparowits Formation, southern Utah, whose mam- occur in the Terlingua fauna, and the only known Cam- mals are now becoming well-known (Eaton, 1987; Ea- panian snakes occur in the Terlingua and Fruitland- ton and Cifelli, 1988; Cifelli, 1990a, b, c, d, e). The Kirtland faunas. Among archosauromorphs, the cer- Kaiparowits assemblages, distributed through 350 m atopsians of southern faunas are also distinct from of section, span a considerable period of time and, northern faunas. Pentaceratops sternbergii (Rowe et al., although quite distinct from more northerly local fau- 198 1) and Chasmosaurus mariscalensis (Lehman, 1982, nas, almost certainly include part or perhaps all of the 1989, 1990a) are endemic to the Fruitland-Kirtland Judithian. The Terlingua fauna shares with the Kai- and Terlingua faunas, respectively. Notably absent from parowits assemblages a new multituberculate taxon, the archosauromorph component of the Terlingua fau- which we referred to above as cf. Cimolodon, following na, and from the Aguja in general, are champsosaurs. Eaton's (1987) suggestion for the Kaiparowits material. They are reported in the San Juan Basin (Wolberg and No other mammalian species have yet been recognized LeMone, 1979) and are abundant in more northern that are shared by the Kaiparowits and Terlingua fau- faunas (Estes, 1964; Langston, 1975, 1976; Brinkman, nas, but this will bear reassessment as the faunas are 1990). more thoroughly studied. The non-mammalian ver- Collectively, the vertebrates of the Terlingua local tebrates are not yet adequately studied to afford in- fauna indicate an appreciable degree of latitudinal dif- formative comparisons. ferentiation among contemporaneous faunas border- The "El Gallo Formation" of Baja California pro- ing the Cretaceous interior seaway. The full signifi- duced the only other Late Campanian non-marine fau- cance of Late Cretaceous faunal differentiation will na known at present (Morris, 1973; Lillegraven, 1972, become clear only after the faunas become known in 1976; Clemens et al., 1979). In the "El Gallo" fauna greater detail. is the only other occurrence of Gallolestes. The "El Gallo" and faunas also share the wide Terlingua rang- ACKNOWLEDGMENTS ing taxa Pediomys and possibly Mesodma, but neither taxon is adequately known in these southern faunas to We are indebted to Dr. Tony Runkle, Mr. Ray Kap- permit more specific comparisons. Absent from the tijna, and Mr. Arnold Rogers for showing us the study Terlingua fauna are polyglyphanodontine squamates, area, and Mr. Wayne Swoboda for providing access to which occur in the "El Gallo" and many northern lo- the site. We also thank Welton and Patty Fiedler for calities (Estes, 1983a). their warm hospitality during our fieldwork. Many col- leagues helped us to identify the Aguja fossils and with the considerable labor that went into their recovery, Campanian Faunal Differentiation including Bud Barnett, Gorden Bell, William Clemens, The composition of the Terlingua local fauna cor- Lowell Dingus, Richard Estes, Jacques Gauthier, Eliz- roborates previous suggestions that latitudinal biotic abeth Gordon, Howard Hutchison, Wann Langston, differentiation developed along the Interior Seaway, Beth Larson, Jay Lillegraven, Ernest Lundelius, David and that a biogeographically distinct southern terres- Polly, Amy Sheldon, Rick Toomey, Hillary Tulley, and trial fauna existed during the Campanian (Clemens, Jack Wilson. For generous access to collections, we 1973; Clemens et al., 1979; Flynn, 1986; Eaton, 1987; thank Drs. Richard Fox, Jeff Eaton, Jay Lillegraven, Lehman, 1987; Wolfe and Upchurch, 1987; Lillegra- Bill Clemens, and Howard Hutchison. This project was ven and Ostresh, 1990). This is not surprising in light supported by the following: NSF BSR 8906992, Pe- of ample evidence of a distinct southern marine biota troleum Research Fund 2031 1-G8 (to RLC), and NSF ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 489

BSR 8958092 and Petroleum Research Fund 21470- the earliest Late Cretaceous of western U.S. Nature 325: G8 (to TBR). We also thank Bill R. Payne, the Owen 520-522. Coates fund, and the Lowe fund of the Geology Foun- and T. B. Rowe. 1990. Therian mammals from the dation of the University of Texas for supporting this Late Cretaceous of south Texas. Journal of Vertebrate research. Paleontology 10 (supplement to No. 3):18A. Clemens, W. A. 1966. Fossil mammals of the type Lance Formation Wyoming. Part II. Marsupialia. University REFERENCES of California Publications in Geological Sciences 62:1- 122. Armstrong-Ziegler, J. G. 1978. An aniliid snake and as- 1973. The roles of fossil vertebrates in interpreta- sociated vertebrates from the Campanian of New Mex- tion of Late Cretaceous stratigraphy of the San Juan ico. Journal of Paleontology 52:480-483. Basin, New Mexico; pp. 154-167 in Four Corners Geo- 1980. Amphibia and Reptilia from the Campanian logical Society Memoir, 1973. of New Mexico. Fieldiana Geology, 4:1-39. 1979. Marsupialia; pp. 192-221 in J. A. Lillegraven, Boreske, J. 1974. A review of North American fossil amiid Z. Kielan-Jaworowska, and W. A. Clemens (eds.), Me- fishes. Bulletin of the Museum of Comparative Zoology sozoic Mammals--The First Two-thirds of Mammalian 146:1-87. History. University of California Press, Berkeley. Brinkman, D. B. 1990. Paleoecology of the Judith River 1980. Gallolestes pachymandibularis (Theria, in- Formation (Campanian) of Dinosaur Provincial Park, certae sedis; Mammalia) from Late Cretaceous deposits Alberta, Canada: evidence from vertebrate microfossil in Baja California del Norte, Mexico. PaleoBios 33:1- localities. Palaeogeography, Palaeoclimatology, Palaeo- 10. ecology 78:37-54. Sand J. A. Lillegraven. 1986. New Late Cretaceous, Brookins, D. G., and J. K. Rigby, Jr. 1987. Geochronologic North American advanced therian mammals that fit nei- and geochemical study of volcanic ashes from the Kirt- ther the marsupial nor eutherian molds; pp. 55-85 in land Formation (Cretaceous), San Juan Basin, New Mex- K. M. Flanagan and J. A. Lillegraven (eds.), Vertebrates, ico; pp. 105-110 in J. E. Fassett and J. K. Rigby, Jr. Phylogeny and Philosophy. A Tribute to George Gay- (eds.), The Cretaceous-Tertiary boundary in the San Juan lord Simpson. Contributions to Geology, University of and Raton Basins, New Mexico and Colorado. Geolog- Wyoming, Special Paper 3. ical Society of America Special Paper 209. Boulder, Col- ,, J. A. Lillegraven, E. H. Lindsay, and G. G. Simpson. orado. 1979. Where, when, and what-a survey of known Me- Brown, B. 1942. The largest known crocodile. Natural His- sozoic mammal distribution; pp. 7-58 in J. A. Lille- tory 49:260-261. graven, Z. Kielan-Jaworowska, and W. A. Clemens (eds.), Bryant, L. J. 1987. A new genus and species of Amiidae Mesozoic Mammals--The First Two-thirds of Mam- (Holostei: Osteichthyes) from the Late Cretaceous of malian History. University of California Press, Berkeley. North America, with comments on the phylogeny of the Colbert, E. H., and R. T. Bird. 1954. A gigantic crocodile Amiidae. Journal of Vertebrate Paleontology 7:349-372. from the Upper Cretaceous beds of Texas. American Butler, P. M. 1978. A new interpretation of the mammal Museum Novitates 1688:1-22. teeth of tribosphenic pattern from the Albian of Texas. Coombs, W. P. 1978. The families of the ornithischian Breviora 446:1-27. dinosaur order Ankylosauria. Palaeontology 21:143-170. Cappetta, H. 1987. Chondrichthyes II: Mesozoic and Ce- and T. Maryanska. 1990. Ankylosauria; pp. 456- nozoic Elasmobranchii. Handbook of Paleoichthyology, 483 in D. B. Weishampel, P. Dodson, and H. Osmolska Vol. 3B. Gustav Fischer, New York, 193 pp. (eds.), The Dinosauria. University of California Press, Carpenter, K. 1990. Ankylosaur systematics: example us- Los Angeles. ing Panoplosaurus and Edmontonia (Anklyosauria: No- Crompton, A. W. 1971. The origin of the tribosphenic dosauridae); pp. 281-298 in K. Carpenter and P. J. Cur- molar; pp. 65-87 in D. M. Kermack and K. A. Kermack rie (eds.), Dinosaur Systematics: Perspectives and (eds.), Early Mammals. Zoological Journal of the Lin- Approaches. Cambridge University Press, Cambridge. nean Society 50 (supplement 1). Cifelli, R. L. 1990a. Cretaceous mammals of southern Utah. Currie, P. J., J. K. Rigby, Jr., and R. E. Sloan. 1990. The- I. Marsupials from the Kaiparowits Formation (Judith- ropod teeth from the Judith River Formation of south- ian). Journal of Vertebrate Paleontology 10:295-319. ern Alberta, Canada; pp. 107-125 in K. Carpenter and 1990b. Cretaceous mammals of southern Utah. IV. P. J. Currie (eds.), Dinosaur Systematics: Perspectives Eutherians from the Wahweap (Aquilan) and Kaiparo- and Approaches. Cambridge University Press, New York. wits (Judithian) formations. Journal of Vertebrate Pa- Davies, K. 1983. Hadrosaurian dinosaurs of Big Bend Na- leontology 10:346-360. tional Park, Brewster County, Texas. M.A. thesis, De- 1990c. Cretaceous mammals of southern Utah. III. partment of Geological Sciences, University of Texas at Therian mammals from the Turonian (early Late Cre- Austin, 236 pp. - taceous). Journal of Vertebrate Paleontology 10:332- and T. M. Lehman. 1989. The WPA Quarries; pp. 345. 32-42 in A. B. Busbey, III, and T. M. Lehman (eds.), 1990d. Cretaceous mammals of southern Utah. II. Vertebrate Paleontology, Biostratigraphy and Deposi- Marsupials and marsupial-like mammals from the Wah- tional Environments, Latest Cretaceous and Tertiary, weap Formation (early Campanian). Journal of Verte- Big Bend Area, Texas. Guidebook, Field Trip Nos. la, brate Paleontology 10:320-331. b, c, Society of Vertebrate Paleontology 49th Annual - 1990e. A primitive higher mammal from the Late Meeting, Austin, Texas. Cretaceous of southern Utah. Journal of Mammalogy Denton, R. K., Jr., R. C. O'Neill, B. S. Grandstaff, and D. 71:343-350. C. Parris. 1991. Earliest record of an advanced glyp- S and J. G. Eaton. 1987. Marsupial mammal from tosaurine lizard from the Late Cretaceous (Campanian) 490 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992

of New Jersey. Journal of Vertebrate Paleontology 11 assigned to the Gerrhonotinae (Squamata: Anguidae). (supplement to No. 3):25A. Journal of Vertebrate Paleontology 8:188-195. Eaton, J. G. 1987. Stratigraphy, depositional environ- Goodwin, M. B., and A. L. Deino. 1989. The first radio- ments, and age of Cretaceous mammal-bearing rocks in metric ages from the Judith River Formation (Upper Utah, and systematics of the Multituberculata (Mam- Cretaceous), Hill County, Montana. Canadian Journal malia). Ph.D. dissertation, University of Colorado, of Earth Sciences 26:1384-1391. Boulder, 308 pp. Hoese, H. D., and R. H. Moore. 1977. Fishes of the Gulf and R. L. Cifelli. 1988. Preliminary report on Late of Mexico; Texas, Louisiana, and adjacent waters. Texas Cretaceous mammals of the Kaiparowits Plateau, south- A&M University Press, College Station, 327 pp. ern Utah. Contributions to Geology, University of Wy- Hutchison, J. H., and J. D. Archibald. 1986. Diversity of oming 26:45-55. turtles across the Cretaceous/Tertiary boundary in Estes, R. 1964. Fossil vertebrates from the Late Cretaceous northeastern Montana. Palaeogeography, Palaeoclima- Lance Formation, Eastern Wyoming. University of Cal- tology, and Palaeoecology 55:1-22. ifornia Publications in Geological Sciences 49:1-180. Kauffman, E. G. 1977. Geological and biological overview: 1969. Relationships of two Cretaceous lizards (Sau- Western Interior Cretaceous Basin. Mountain Geologist ria, Teiidae). Breviora 317:1-8. 14:75-99. 1981. Gymnophiona, Caudata. Handbuch der Pa- 1984. Paleobiogeography and evolutionary re- liioherpetologie, P. Wellnhofer (ed.), Part 2. Gustav sponse dynamic in the Cretaceous Western Interior Sea- Fischer Verlag, Stuttgart, 115 pp. way of North America; pp. 273-306 in G. E. G. Wes- 1983a. Sauria terrestria, Amphisbaenia. Handbuch termann (ed.), Jurassic-Cretaceous Paleogeography of der Paliioherpetologie, P. Wellnhofer (ed.), Part 10a. North America. Geological Association of Canada, Spe- Gustav Fischer Verlag, Stuttgart, 249 pp. cial Paper 27. 1983b. The fossil record and early distribution of Kequin, G., and R. C. Fox. 1991. New teiid lizards from lizards; pp. 365-398 in A. G. J. Rhodin and K. Miyata the Upper Cretaceous Oldman Formation (Judithian) of (eds.), Advances in Herpetology and Evolutionary Bi- southeastern Alberta, Canada, with a review of the Cre- ology. Museum of Comparative Zoology, Harvard Uni- taceous record of teiids. Annals of Carnegie Museum 60: versity. 145-162. and A. Baiez. 1985. Herpetofaunas of North and Kielan-Jaworowska, Z., J. G. Eaton, and T. M. Bown. 1979. South America during the Late Cretaceous and Ceno- Theria of metatherian-eutherian grade; pp. 182-191 in zoic: evidence for interchange?; pp. 139-179 in F. G. J. A. Lillegraven, Z. Kielan-Jaworowska, and W. A. Stehli and S. D. Webb (eds.), The Great American Biotic Clemens (eds.), Mesozoic Mammals--The First Two- Interchange. Plenum Press, New York and London. thirds of Mammalian History. University of California -), K. de Queiroz, and J. Gauthier. 1988. Phylogenetic Press, Berkeley. relationships within Squamata; pp. 119-281 in R. Estes Krause, D. W., and D. Baird. 1979. Late Cretaceous mam- and G. Pregill (eds.), Phylogenetic Relationships of the mals east of the North American Interior Seaway. Jour- Lizard Families. Stanford University Press, Stanford. nal of Paleontology 53:562-565. Ethridge, R., and K. de Queiroz. 1988. A phylogeny of Langston, W., Jr. 1975. The ceratopsian dinosaurs and as- Iguanidae; pp. 283-367 in R. Estes and G. Pregill (eds.), sociated lower vertebrates from the St. Mary River For- Phylogenetic Relationships of the Lizard Families. Stan- mation (Maastrichtian) at Scabby Butte, Southern Al- ford University Press, Stanford. berta. Canadian Journal of Earth Science 12:1576-1608. Flynn, L. J. 1986. Late Cretaceous mammal horizons from 1976. A Late Cretaceous vertebrate fauna from the the San Juan Basin, New Mexico. American Museum St. Mary River Formation in western Canada; pp. 114- Novitates 2845:1-30. 133 in C. S. Churcher (ed.), Athlon: Essays on Paleon- Fox, R. C. 1971. Early Campanian multituberculates tology in Honor of Loris Shano Russell. Royal Ontario (Mammalia: Allotheria) from the Upper Milk River For- Museum, Toronto. mation, Alberta. Canadian Journal of Earth Sciences 8: , B. Standhardt, and M. Stevens. 1989. Fossil ver- 916-938. •- tebrate collecting in the Big Bend-history and retro- 1975. Molar structure and function in the Early spective; pp. 11-21 in A. B. Busbey, III, and T. M. Cretaceous mammal Pappotherium: evolutionary im- Lehman (eds.), Vertebrate Paleontology, Biostratigraphy plications for Mesozoic Theria. Canadian Journal of Earth and Depositional Environments, Latest Cretaceous and Sciences 12:412-442. Tertiary, Big Bend Area, Texas. Guidebook, Field Trip 1987. An ancestral marsupial and its implications Nos. la, b, c, Society of Vertebrate Paleontology 49th Annual Texas. for early marsupial evolution; pp. 101-105 in P. J. Currie Meeting, Austin, and E. H. Koster (eds.), Fourth Symposium on Mesozoic Lawson, D. A. 1972. Paleoecology of the Tornillo For- Terrestrial Ecosystems. Occasional Paper 3, Tyrrell Mu- mation, Big Bend National Park, Brewster County, Tex- seum of Palaeontology, Drumheller. as. M.A. thesis, University of Texas at Austin, 182 pp. Gauthier, J. A. 1982. Fossil xenosaurid and anguid lizards S1976. Tyrannosaurus and Torosaurus, Maastricht- from the early Eocene Wasatch Formation, southeast ian dinosaurs from Trans-Pecos Texas. Journal of Pa- Wyoming, and a revision of the Anguioidea. Contri- leontology 50:158-164. butions to Geology, University of Wyoming 21:7-54. Lehman, T. M. 1982. A ceratopsian bone bed from the , K. de Queiroz, and R. Estes. 1988. Phylogenetic Aguja Formation (Upper Cretaceous), Big Bend Na- relationships within Squamata; pp. 15-98 in R. Estes tional Park, Texas. M.A. thesis, Department of Geolog- and G. Pregill (eds.), Phylogenetic Relationships of the ical Sciences, University of Texas at Austin, 209 pp. Lizard Families. Stanford University Press, Stanford. 1985a. Sedimentology, stratigraphy, and paleon- Good, D. A. 1988. The phylogenetic position of fossils tology of Upper Cretaceous (Campanian-Maastrichtian) ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 491

sedimentary rocks in Trans-Pecos Texas. Ph.D. disser- Baja California. National Geographic Society Research tation, University of Texas at Austin, 299 pp. Reports, 1966 Projects:197-209. 1985b. Transgressive-regressive cycles and envi- Nessov, L. A. 1985. New Cretaceous mammals in the Ki- ronments of coal deposition in upper Cretaceous strata zylkum Desert. Vestnik Leningradskovo Universitete, of Trans-Pecos Texas. Gulf Coast Association of Geo- Geologiyia, Geografaiyia, Leningrad 17:8-18. [Russian] logical Societies Transactions, 35:431-438. Nicholls, E. L., and A. P. Russell. 1990. Paleobiogeography 1986. Late Cretaceous sedimentation in Trans-Pe- of the Cretaceous Western Interior Seaway of North cos Texas. West Texas Geological Society Bulletin 25: America: the vertebrate evidence. Palaeogeography, Pa- 4-9. laeoclimatology, Palaeoecology 79:149-169. 1987. Late Maastrichtian paleoenvironments and Patterson, B. 1956. Early Cretaceous mammals and the dinosaur biogeography in the Western Interior of North evolution of mammalian molar teeth. Fieldiana, Geol- America. Palaeogeography, Palaeoclimatology, and ogy 13:1-105. Palaeoecology 60:189-217. Rage, J. C. 1984. Serpentes. Handbuch per Palioherpeto- 1989. Chasmosaurus mariscalensis, sp. nov., a new logie, part 11, Gustav Fischer Verlag, 80 pp. ceratopsian dinosaur from Texas. Journal of Vertebrate Reeside, J. B. 1927. The cephalopods of the Eagle Sand- Paleontology 9:137-162. stone and related formations in the Western Interior of S1990a. The ceratopsian subfamily Chasmosaurinae: the United States. United States Geological Survey, Pro- sexual dimorphism and systematics; pp. 211-229 in K. fessional Paper 151, 87 pp. Carpenter and P. J. Currie (eds.), Dinosaur Systematics: Reig, O., J. A. Kirsch, and L. G. Marshall. 1987. Systematic Perspectives and Approaches. Cambridge University relationships of the living and neocenozoic American Press, New York. "opossum-like" marsupials (Suborder Didelphimor- S1990b. Paleosols and the Cretaceous/Tertiary tran- pha), with comments on the classification of these and sition in the Big Bend region of Texas. Geology 18:362- of the Cretaceous and Paleogene New World and Eu- 364. ropean metatherians; pp. 1-89 in M. Archer (ed.), Pos- Lillegraven, J. A. 1969. Latest Cretaceous mammals of sums and Opossums: Studies in Evolution. Surrey Beatty upper part of Edmonton Formation of Alberta, Canada, & Sons and the Royal Zoological Society of New South and review of marsupial-placental dichotomy in mam- Wales, Sydney. malian evolution. Paleontological Contributions, Uni- Reynolds, R. E. 1983. Laboratory methodology; in Pale- versity of Kansas 50 (Vertebrata 12): 1-122. ontological Salvage, Highway 138, Borrow Cut, Cajon 1972. Preliminary report on Late Cretaceous mam- Pass, San Bernardino County, California. Reports, Cal- mals from the El Gallo Formation, Baja California del ifornia Department of Transportation, District VIII, San Norte, Mexico. Contributions in Science, Natural His- Bernardino. tory Museum of Los Angeles County 232:1-11. Rigby, J. K., and D. L. Wolberg. 1987. The therian mam- 1976. A new genus of therian mammals from the malian fauna (Campanian) of Quarry 1, Fossil Forest Late Cretaceous "El Gallo Formation," Baja California, study area, San Juan Basin, New Mexico. Geological Mexico. Journal of Paleontology 50:437-444. Society of America, Special Paper 209:51-79. S and M. C. McKenna. 1986. Fossil mammals from Rowe, T., E. H. Colbert, and J. D. Nations. 1981. On the the "Mesaverde" Formation (Late Cretaceous, Judith- occurrence of Pentaceratops (Reptilia, Ceratopsia), with ian) of the Bighorn and Wind River basins, Wyoming, a description of its frill; pp. 29-48 in S. Lucas, J. K. with definitions of Late Cretaceous North American Rigby, and B. Kues (eds.), Advances in San Juan Basin Land-mammal "ages." American Museum Novitates Paleontology. University of New Mexico Press, Albu- 2840:1-68. querque. D. A. 1975. and the Creta- - and L. M. Ostresh. 1990. Late Cretaceous (earliest Russell, Reptilian diversity transition in North Campanian/Maastrichtian) evolution of western shore- ceous-Tertiary America; pp. 119- in W. Caldwell The Cretaceous in the lines of the North American Western Interior Seaway 136 (ed.), System Western Interior of North America. Asso- in relation to known mammalian faunas. Geological So- Geological ciation of Canada no. Toronto. ciety of America, Special Paper 243:1-30. Special Paper 13, 1982. The mass extinction of the Late Cretaceous. R. J. T. R. T. and J. A. Maxwell, A., Lonsdale, Hazzard, Scientific American 246:58-65. Wilson. 1967. of Bend National Geology Big Park, 1988. A check list of North American marine Cre- Brewster County, Texas. University of Texas Publica- taceous vertebrates including fresh water fishes. Occa- tion 6711, Bureau of Economic Geology, 320 pp. sional Papers of the Tyrrell Museum 4:1-57. M. C. 1965. microvertebrates McKenna, Collecting by Sahni, A. 1972. The vertebrate fauna of the Judith River and 193-203 in and washing screening; pp. B. Kummel Formation, Montana. Bulletin of the American Museum D. M. Handbook of Raup (eds.), Paleontological Tech- of Natural History, 147:321-412. W. H. San Francisco. niques. Freeman, Schiebout, J. A. 1974. Vertebrate paleontology and paleo- McNulty, C. L., and B. H. Slaughter. 1962. A new sawfish ecology of the Paleocene Black Peaks Formation, Big from the Woodbine Formation (Cretaceous) of Texas. Bend National Park, Texas. Texas Memorial Museum Copeia 1962:775-777. Bulletin 24:1-88. - and - 1972. The Cretaceous Selachian genus Slaughter, B. H., and M. Steiner. 1968. Notes on rostral Ptychotrygon Jaekel 1894. Eclogae Geologiae Helvetiae teeth of ganopristine sawfishes, with special references 65:647-656. to Texas material. Journal of Paleontology 42:233-239. Meszoely, C. A. M. 1970. North American fossil anguid Sohl, N. F. 1971. North American Cretaceous biotic prov- lizards. Bulletin of the Museum of Comparative Zoology inces delineated by gastropods. Proceedings of the North 139:87-150. American Paleontological Convention 2:1610-1637. Morris, W. J. 1973. Mesozoic and Tertiary vertebrates in - and R. A. Christopher. 1983. The Black Creek- 492 JOURNAL OF VERTEBRATE PALEONTOLOGY, VOL. 12, NO. 4, 1992

Peedee formational contact (Upper Cretaceous) in the Wilson, J. A. 1977. Stratigraphic occurrence and correla- Cape Fear River region of North Carolina. United States tion of Early Tertiary vertebrate faunas, Trans-Pecos Geological Survey, Professional Paper 1285, 37 pp. Texas. Texas Memorial Museum Bulletin 25:1-42. - and E. G. Kauffman. 1964. Giant Upper Cretaceous 1984. Vertebrate faunas 49 to 36 million years ago oysters from the Gulf Coast and Caribbean. United States and additions to species of Leptoreodon (Mammalia: Geological Survey, Professional Paper 483-H, 22 pp. Artiodactyla) found in Texas. Journal of Vertebrate Pa- Standhardt, B. R. 1986. Vertebrate paleontology of the leontology 4:199-207. Cretaceous/Tertiary transition of Big Bend National Park, 1986. Stratigraphic occurrence and correlation of Texas. Ph.D. dissertation, Louisiana State University, early Tertiary vertebrate faunas, Trans-Pecos Texas: Agua Baton Rouge, 298 pp. Fria-Green Valley areas. Journal of Vertebrate Paleon- Stevens, J. B., M. S. Stevens, and J. A. Wilson. 1984. Dev- tology 6:350-373. il's Graveyard Formation (new) Eocene and Oligocene --, P. C. Twiss, R. K. DeFord, and S. E. Clabaugh. Age Trans-Pecos Texas. Texas Memorial Museum Bul- 1968. Stratigraphic succession, potassium-argon dates, letin 32:1-21. and vertebrate faunas, Vieja Group, Rim Rock country, Stevens, M. S., J. B. Stevens, and M. R. Dawson. 1969. Trans-Pecos Texas. American Journal of Science 266: New early Miocene Formation and vertebrate local fau- 590-604. na, Big Bend National Park, Brewster County, Texas. Winkler, D. A., P. A. Murry, and L. L. Jacobs. 1990. Early Pearce Sellards Series 51:1-53. Cretaceous (Comanchean) vertebrates of central Texas. Sullivan, R. M. 1981. Fossil lizards from the San Juan Journal of Vertebrate Paleontology 10:95-116. Basin, New Mexico; pp. 76-88, in S. Lucas, J. K. Rigby, Wixson, B. G. 1963. Fossil shark teeth in the study of Jr., and B. Kues (eds.), Advances in San Juan Basin Cretaceous environments near Terlingua, Texas. Texas Paleontology. University of New Mexico Press, Albu- Journal of Science 15:415-416. querque. Wolberg, D. L., and D. E. LeMone. 1979. Paleontology of 1982. Fossil lizards from the Swain Quarry, "Fort Fruitland Formation near Bisti, San Juan Basin, New Union Formation," Middle Paleocene (Torrejonian), Mexico-a progress report. New Mexico Bureau of Carbon County, Wyoming. Journal of Paleontology 56: Mines, Annual Report:55-57. 996-1010. Wolfe, J. A., and G. R. Upchurch, Jr. 1987. North Amer- 1987. A reassessment of reptilian diversity across ican nonmarine climates and vegetation during the Late the Cretaceous-Tertiary boundary. Natural History Mu- Cretaceous. Palaeogeography, Palaeoclimatology, and seum of Los Angeles County, Contributions in Science, Palaeoecology 61:33-37. 391, 26 pp. Wolleben, J. A. 1977. Paleontology of the Difunta Group Weishampel, D. B. 1990. Dinosaurian distribution; pp. 63- (Upper Cretaceous-Tertiary) in northern Mexico. Jour- 139 in D. B. Weishampel, P. Dodson, and H. Osm6lska nal of Paleontology 51:373-398. (eds.), The Dinosauria. University of California Press, Young, K. 1963. Upper Cretaceous ammonites from the Los Angeles. Gulf Coast of the United States. University of Texas, and J. Horner. 1990. Hadrosauridae; pp. 534-561 Bureau of Economic Geology Publication no. 6304, 373 in D. B. Weishampel, P. Dodson, and H. Osmolska pp. (eds.), The Dinosauria. University of California Press, Los Angeles. Received 22 August 1991; accepted 22 January 1992.

APPENDIX 1

Voucher specimens for taxa from the Terlingua local fauna 43057-258; Prosirinidae sp. TMM 43057-259; Scapher- mentioned in the text. petontidae TMM 43057-248; Urodela indet. TMM 43057- 237, TMM 43057-239; Anura indet. TMM 43057-238, CHONDRICHTHYES: Hybodus sp. TMM 43057-289, TMM 43057-256, TMM 43057-310, TMM 43057-311, TMM 43057-293, TMM 43057-321; Hybodontidae, in- OMNH 25293, OMNH 25305. det. TMM 43057-290, TMM 43057-291; Lissodus sela- CHELONIA: Baenidae OMNH 23143; "Aspideretes" TMM chos TMM 43057-294, TMM 43057-302; Scapanorhyn- 43057-324; isolated dentaries: TMM 43057-129; TMM chys sp. TMM 43057-301; Onchopristis dunklei TMM 43057-130; TMM 43057-131; TMM 43057-132; TMM 43057-295, TMM 43057-305; Ischyrhiza avonicola TMM 43057-133. 43057-292, TMM 43057-306; Squatirhina americana SQUAMATA: Odaxosaurus sp. TMM 43057-278, TMM TMM 43057-297, TMM 43057-298; Ptychotrygon sp. 43057-279, TMM 43057-280, OMNH 25226; Proxestops TMM 43057-300, TMM 43057-304; Batomorphii indet. sp. TMM 43057-138; Glyptosaurinae indet. TMM 43057- TMM 43057-307; Dasyatidae indet. TMM 43057-296; 281, TMM 43057-282, TMM 43057-283, OMNH 22981, Chondrichthyes indet. TMM 43057-303. OMNH 25232, OMNH 25251; Restes sp. OMNH 25337; ACTINOPTERYGII: Leipsosteidae TMM 43057-34, TMM Anguidae indet. OMNH 23035 (in part), OMNH 23038 43057-242, TMM 43057-243, TMM 43057-245; Amiidae (in part), OMNH 23035; Necrosauridae indet. TMM TMM 43057-246; Phyllodontidae TMM 43057-244. 43057-266, OMNH 25222, OMNH 25334; Sauriscus sp. LISSAMPHIBIA: Albanerpeton cf. A. nexosus TMM TMM 43057-284, TMM 43057-285, OMNH 25336, 43057-247, TMM 43057-249, TMM 43057-250, TMM OMNH 25339, OMNH 25341, OMNH 25347; Scincidae 43057-251, TMM 43057-252, TMM 43057-253, TMM sp. A TMM 43057-286, TMM 43057-287, TMM 43057- 43057-254, TMM 43057-255, TMM 43057-257, TMM 288, OMNH 23034, OMNH 23039, OMNH 25223, ROWE ET AL.- VERTEBRATES OF THE CRETACEOUS AGUJA FORMATION 493

OMNH 25225, OMNH 25227, OMNH 25242; Teiidae TMM 43057-323; cf. Ricardoestesia TMM 43057-313; cf. sp. B TMM 43057-274, TMM 43057-275, TMM 43057- Dromaeosaurus TMM 43057-314; cf. Saurornitholestes 276, OMNH 23037, OMNH 25339, OMNH 25342, TMM 43057-316, 43057-317. OMNH 25343; Squamata indet. sp. X TMM 43057-261, MAMMALIA: Meniscoessus, sp. nov. TMM 43057-62, TMM 43057-263, TMM 43057-264, TMM 43057-265, 43057-63, 43057-64, OMNH 22667, 25089; Cimolodon TMM 43057-273, OMNH 25224; Squamata indet. sp. Y cf. electus OMNH 22658, 22661, 22692, 25038, 25041, TMM 43057-267, TMM 43057-268, TMM 43057-269, 25005, 25006, 25042; cf. Cimolodon 22670, 22673, 23031, TMM 43057-270, TMM 43057-271, OMNH 22982, 23032, 25035, 25088; Cimolomys clarki OMNH 22682, OMNH 23040; Serpentes TMM 43057-322. 25014; Multituberculata, incertae sedis sp. nov. OMNH ARCHOSAURIA: Goniopholidae indet. TMM 43057-6; 22683, 25019. Alphadon cf. A. wilsoni OMNH 25217; Deinosuchus TMM 43057-20, TMM 43057-147; Ptero- Alphadon, sp. OMNH 22721; Turgidodon sp. TMM 43057- sauria TMM 43057-13; Ankylosauria TMM 43057-136; 82; Pediomys sp. cf. P. krejcii OMNH 22748; Gallolestes Hadrosauridae TMM 43057-145; TMM 43057-146; TMM sp. OMNH 22788; Mammalia, incertae sedis ("metathe- 43057-152; Ceratopsidae TMM 43057-32; cf. Troodon rian-eutherian grade" or "Tribotheria") OMNH 22786.