Boletín de la Sociedad Geológica Mexicana ISSN: 1405-3322 Sociedad Geológica Mexicana, A.C. Rivera-Sylva, Héctor E.; Carbot-Chanona, Gerardo; Vivas- González, Rafael; Nava-Rodríguez, Lizbeth; Cabral-Valdéz, Fernando The first crocodyliforms remains from La Parrita locality, Cerro del Pueblo Formation (Campanian), Coahuila, Mexico Boletín de la Sociedad Geológica Mexicana, vol. 71, no. 3, 2019, September-December, pp. 727-739 Sociedad Geológica Mexicana, A.C. DOI: https://doi.org/10.18268/BSGM2019v71n3a6 Available in: https://www.redalyc.org/articulo.oa?id=94366148006 How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Journal's webpage in redalyc.org Portugal Project academic non-profit, developed under the open access initiative Boletín de la Sociedad Geológica Mexicana / 2019 / 727 The first crocodyliforms remains from La Parrita locality, Cerro del Pueblo Formation (Campanian), Coahuila, Mexico Héctor E. Rivera-Sylva, Gerardo Carbot-Chanona, Rafael Vivas-González, Lizbeth Nava-Rodríguez, Fernando Cabral-Valdéz ABSTRACT Héctor E. Rivera-Sylva ABSTRACT RESUMEN Fernando Cabral-Valdéz Departamento de Paleontología, Museo del Desierto, Carlos Abedrop Dávila 3745, 25022, The record of land tetrapods of El registro de tetrápodos terrestres en la Saltillo, Coahuila, Mexico. the Cerro del Pueblo Formation Formación Cerro del Pueblo (Cretácico (Late Cretaceous, Campanian), in Gerardo Carbot-Chanona tardío, Campaniano) en Coahuila, incluye Coahuila, includes turtles, pterosaurs, [email protected] tortugas, pterosaurios, dinosaurios y Museo de Paleontología “Eliseo Palacios Aguil- dinosaurs, and crocodyliforms. This era”, Secretaría de Medio Ambiente e Historia last group is represented only by crocodyliformes. Este último grupo está Natural. Calzada de los hombres ilustres s/n, representado por goniofólididos, eusuquios 29000, Tuxtla Gutiérrez, Chiapas, Mexico. goniopholidids, indeterminate eusu- chians, and Brachychampsa montana. In indeterminados y Brachychampsa montana. Rafael Vivas-González this work we report the first crocodyli- En este trabajo se reportan los primeros Villa Nápoles 6506, Colonia Mirador de las Mitras, 64348, Monterrey, N. L., Mexico. form remains from La Parrita locality, restos de crocodyliformes de la localidad Cerro del Pueblo Formation, based La Parrita, Formación Cerro del Pueblo, Lizbeth Nava-Rodríguez on one isolated tooth, vertebrae, and con base en un diente aislado, vértebras y Facultad de Ingeniería, Universidad Autóno- osteoderms. The association of croc- ma de San Luis Potosí, Dr. Manuel Nava 8, osteodermos. La asociación de crocodyli- Zona Universitaria Poniente, San Luis Potosi, odyliforms, turtles, dinosaurs, and formes, tortugas, dinosaurios y oogonias S.L.P., Mexico. charophyte oogonia provide evidence for stagnant to fluvial environments de cariofitas, proporcionan evidencia de on a delta plain with tropical climate ambientes fluviales en una llanura deltaica for the Cerro del Pueblo Formation de tipo tropical para la Formación Cerro during the Late Cretaceous. del Pueblo durante el Cretácico tardío. Keywords: Crocodyliforms, Palabras clave: Crocodyli- Globidonta, Late Cretaceous, formes, Globidonta, Cretácico Coahuila, Mexico. tardío, Coahuila, México. BOL. SOC. GEOL. MEX. 2019 VOL. 71 NO. 3 P. 727 ‒ 739 http://dx.doi.org/10.18268/BSGM2019v71n3a6 Manuscript received: January 5, 2018. Corrected manuscript received: April 10, 2018. Manuscript accepted: April 21, 2018. Crocodyliforms remains from La Parrita, Coahuila 728 / Boletín de la Sociedad Geológica Mexicana / 2019 1. Introduction mondi et al., 2015; Hastings et al., 2016), but Globidonta is explicitly a stem-based group, and The fossil record of land vertebrates from the Alligatoridae is node-based (Brochu, 1999). Fur- Cerro del Pueblo Formation in Coahuila includes thermore, some Late Cretaceous North American INTRODUCTION / GEOLOGICAL SETTING AND PALEOENVIRONMENT turtles, squamates, crocodyliforms, pterosaurs, and globidontans were excluded from Alligatoridae in dinosaurs. The turtle record includes a pleurodire earlier analyses (e.g., Brochu, 2004; Martin and with similarities to Chedighaii, the paracryptodires Lauprasert, 2010), such as Stangerochampsa mccabei Compsemys and Neurankylus, the cheloniid Mexiche- from the Early Maastrichtian Horseshoe Canyon lys coahuilaensis, the kinosternid Hoplochelys, the Formation, southern Alberta (Wu et al., 1996); trionychid Adocus, and indeterminate chelydrid, Albertochampsa langstoni from the middle Campan- kinosternoid, and trionychid remains (Brink- ian Dinosaur Park Formation of southern Alberta man, 2014). The only squamate is “Coniophis” (Erickson, 1972), and Brachychampsa reported sp., a taxon based on vertebrae collected near from several sites of early Campanian through Rincon Colorado (Aguillon-Martinez, 2010). late Maastrichtian age throughout western North Pterosaurs are represented by one indeterminate America (Gilmore, 1911; Carpenter and Lindsay, ornithocheiroid (Frey and Stinnesbeck, 2014). 1980; Bryant, 1989; Norell et al., 1994; Williamson, The dinosaur record comprises the hadrosaurids 1996; Sullivan and Lucas, 2003; Monroy Mújica, Velafrons coahuilensis and Latirhinus uistlani, the cera- 2009; Aguillon-Martinez, 2010; Irmis et al., 2013). topsian Coahuilaceratops magnacuerna, ankylosaurids, Two species of Brachychampsa are recognized: B. the dromeosaurids Tröodon and Saurornitholestes, the sealeyi from the Campanian De-Na-Zin Member problematic coelurosaur Richardoestesia, tyranno- of the Kirtland Formation, San Juan Basin, New saurids, and ornithomimosaurs (Rivera-Sylva and Mexico (Williamson, 1996); and the type species, Carpenter, 2014a, 2014b). Records of crocodyli- B. montana from the Hell Creek Formation of forms in the Cerro del Pueblo Formation include Montana (Gilmore, 1911; Bryant, 1989; Norell et indeterminate eusuchian and goniopholidid mate- al., 1994) and possibly elsewhere in western North rial (Rodríguez-de la Rosa and Cevallos-Ferriz, America. 1998), along with a skull table, two frontal bones, Institutional abbreviations: CPC, Colección Pale- isolated teeth, and isolated osteoderms that Agu- ontológica de Coahuila (Paleontological Collec- illon-Martinez (2010) referred to the globidontan tion of Coahuila), Museo del Desierto (MUDE), alligatoroid Brachychampsa montana. Saltillo, Coahuila, Mexico. The material described in the present work comes from the La Parrita locality, located 54 km to the west of Saltillo (Figure 1), and includes fragments 2. Geological setting and of a maxilla and lower jaw, vertebrae, osteoderms, paleoenvironment and one bulbous tooth. The morphology of the tooth allows the classification as Globidonta, and The locality of La Parrita is part of the Cerro del thus is the second record of this clade of croco- Pueblo Formation, which is the oldest geologic dyliforms in the Cerro del Pueblo Formation, formation from the Difunta Group (Figure 2A). Coahuila. The rest of the material can only be The Cerro del Pueblo Formation is dated between assigned as Eusuchia. 71 and 72.5 million years old (Obradovich, 1993; Globidonta is an alligatoroid clade characterized, Eberth et al., 2004), which indicates Campanian at least ancestrally, by the presence of bulbous age. The Cerro del Pueblo Formation was depos- posterior teeth. Its content in recent phylogenetic ited under marginal marine and shallow marine analyses is redundant with that of Alligatoridae conditions, which were influenced by sea-level (e.g., Brochu, 2011; Skutchas et al., 2014; Salas-Gis- oscillations and storm events (Eberth et al., 2004). Crocodyliforms remains from La Parrita, Coahuila Boletín de la Sociedad Geológica Mexicana / 2019 / 729 GEOLOGICAL SETTING AND PALEOENVIRONMENT Figure 1 Location of the La Parrita locality (red star), Cerro del Pueblo Formation, Coahuila state. The facies suggest deltaic systems with shallow Above the base follows a 0.30 m layer consisting flow channels, oxbow or residual lakes, bays and of exfoliated siltstones with a high concentra- lagoons, coastal swamps, and wetlands with exu- tion of oysters of diverse size, which indicate a berant vegetation (McBride, 1974; Hill, 1988). brackish environment. According to Stinnesbeck The stratigraphic sequence that outcrop in La and Frey (2014), the Cerro del Pueblo Formation Parrita locality is composed of alternating layers sandstone and siltstone deposits are character- of sandstone, siltstone and shale (Figure 2B). At istic of brackish conditions, indicated by oyster the base, it is comprised of 0.20 m of ochre-gray banks and abundant non-ostrean bivalves and shales with greenish tonalities. Marine taxa such gastropods. Above the siltstone lies a 0.90 m as the ammonite Sphenodiscus and some isolated, hard, massive, coarse-grained sandstone layer weathered dinosaur bones are associated with with high concentrations of gastropods at the this layer. According to Eberth et al. (2004: 350- top, which indicates marine costal environments 352, fig.5), Sphenodiscus is present in facies 1 cor- (Vivas-González, 2013). A grit layer continues responding to the Parras Shale, which means this by 1 m above, with a 0.40 m thick concentration first layer is the base in which Cerro del Pueblo of gastropods lies above the grit. The next layer Formation is supported (Vivas-González, 2013). consists of 10 m of ochre-gray shale characterized Crocodyliforms remains from La Parrita, Coahuila