Découverte de plaques osseuses d’Ankylosauridé (Dinosauria : Thyreophora) du Crétacé supérieur de la Formation Cerro del Pueblo à Coahuila, Mexique

Découverte de plaques osseuses d’Ankylosauridé (Dinosauria : Thyreophora) du Crétacé supérieur de la Formation Cerro del Pueblo à Coahuila, Mexique.- Des plaques osseuses d’un ankylosauridé ont été découvertes dans la localité El Palmar, commune de General Cepeda, SE de l’État de Coahuila. Ces fossiles proviennent de couches sédimentaires appartenant à la Formation Cerro del Pueblo (Crétacé supérieur : Campanien) du Groupe Difunta. Le matériel comprend des plaques osseuses identifiées comme appartenant à la famille Ankylosauridae et d’autres fragments associés qui n’ont pas été identifiés. Nous présentons ici la première description détaillée de matériel de ce type provenant de l’État de Coahuila.Ankylosaurian dinosaur osteoderms have been discovered in the southeastern part of the State of Coahuila, Mexico, in the township of General Cepeda, in the locality known as El Palmar. The osteoderms were collected from rocks that had been correlated to the Cerro del Pueblo Formation (Late Cretaceous: Campanian) of the Difunta Group. The fossil material includes four dermal scutes and three associated fragments that at present cannot be identified. This is the first description of ostoederms and ankylosaurian material from Coahuila

Evidencia de depredación en una vértebra de un dinosaurio hadrosáurido del Cretácico Superior (Campaniano) de Coahuila, México

Dans des sédiments appartenant à la Formation Aguja (Crétacé supérieur : Campanian) près de La Salada dans le nord de l’état de Coahuila, Mexique, plusieurs fossiles de vertébrés parmi lesquels des Hadrosauridae ont été découverts. Une vertèbre d’hadrosaure suggère une prédation, probablement par un crocodilien géant Deinosuchus riograndensis.En los sedimentos relacionados a la Formación Aguja (Cretácico Tardío: Campaniano) cerca de La Salada en el norte del Estado de Coahuila, México, se han descubierto diversos fósiles de vertebrados incluyendo Hadrosauridae. Una vértebra de hadrosáurido muestra evidencia de depredación posiblemente por Deinosuchus riograndensis.In sediments of the Aguja Formation (Late Cretaceous: Campanian) at La Salada in northern part of the state of Coahuila, Mexico, numerous fossils of vertebrates have been discovered including Hadrosauridae. One hadrosaur vertebra provides evidence of predation probably by a giant alligator Deinosuchus riograndensis

Late Cretaceous Nodosaurids (Ankylosauria: Ornithischia) from Mexico

Restos de anquilosaurios nodosáuridos del Cretácico Superior de México son descritos aquí. Las muestras proceden de la Formación El Gallo de Baja California, de las formaciones Pen y Aguja del noroeste de Coahuila, y de la Formación Cerro del Pueblo, sureste de Coahuila, México. Estas muestras presentaron diferencias significativas con otros nodosáuridos conocidos, incluyendo el cúbito con olécranon bien desarrollado y la muesca del húmero prominente, el extremo distal del fémur de diferente medida no visto en otros nodosáuridos, y una espina similar a un cuerno con los surcos vasculares en un lado. Las muestras son importantes porque son los hallazgos más meridionales de América del Norte, y proporcionan un vínculo biogeográfico importante entre los nodosáuridos de los Estados Unidos y Canadá, por un lado, y Argentina y la Antártida por el otro.Nodosaurid ankylosaur remains from the Upper Cretaceous of Mexico are summarized. The specimens are from the El Gallo Formation of Baja California, the Pen and Aguja Formations of northwestern Coahuila, and the Cerro del Pueblo Formation of southeast Coahuila, Mexico. These specimens show differences from other known nodosaurids, including an ulna with a well developed olecranon and prominent humeral notch, the distal end of the femur not flaring to the extent seen in other nodosaurids, and a horn-like spine with vascular grooves on one side. The specimens represent the southernmost occurrences of nodosaur remains in North America, and provide an important biogeographical link between nodosaurids of the United States and Canada on the one hand, and Argentina and Antarctica on the other

A Centrosaurine (Dinosauria: Ceratopsia) from the Aguja Formation (Late Campanian) of Northern Coahuila, Mexico

<div><p>While centrosaurines and ceratopsids in general are abundant in the Late Campanian of northern Laramidia, they are much less commonly found in southern Laramidia. This has supported hypotheses of dinosaur provinciality and endemism in the Late Cretaceous with the delineation of at least two separate faunal zones, north and south Laramidia. There have been 12 genera of centrosaurines recognized from northern Laramidia while two genera, <i>Diabloceratops</i> and <i>Nasutoceratops</i>, have been named from southern Laramidia. We present an osteological description and taphonomic outline for a new centrosaurine ceratopsid from the Aguja Formation of northern Coahuila, Mexico that is not currently diagnosable to the generic level, but likely represents a new taxon. Further, we have included three-dimensional surface scans of all material attributed to this animal. Considering the large number of centrosaurines from northern Laramidia, it is likely that cladistic analyses are biased towards this faunal zone. New findings of southern centrosaurines are needed to correct this bias. This discovery expands the range of centrosaurines south to Coahuila, Mexico and adds new information to better characterize the morphology and taxonomy of centrosaurines from southern Laramidia and their evolution in comparison to their northern counterparts.</p></div

CPC 274 Dorsal Vertebra- A complete dorsal centrum and ventral neural arch in (A) cranial, (B) left lateral, (C) caudal, and (D) right lateral views.

<p>Scale = 10 cm.</p

CPC 274 Squamosal- The right squamosal of CPC 274 in (A) lateral and (B) medial views.

<p>Scale = 5 cm. Inset showing the rugose lateral bump. Scale = 5 cm.</p

CPC 274 Parietal- The partial fragment of CPC 274 in both front and back views (A, B).

<p>No parietal edge is preserved in this fragment. Scale = 10 cm.</p

Squamosal Measurements.

<p>Squamosal Measurements.</p

CPC 274 Left Scapula- The complete left scapula of CPC 274 in (A) lateral and (B) medial views.

<p>Scale = 10 cm.</p