A Late Cretaceous dinosaur and crocodyliform faunal association–based on isolate teeth and osteoderms–at Cerro Fortaleza Formation (Campanian-Maastrichtian) type locality, Santa Cruz, Argentina

The Late Cretaceous dinosaur record in southern South America has been improved recently; particularly with findings from Chorrillo and Cerro Fortaleza formations, both bearing ankylosaur remains, a clade that was not previously recorded in the Austral Basin. The dinosaur fauna of the type locality of Cerro Fortaleza Formation is known from -and biased to- large-sized sauropod remains and a single described taxon, the titanosaur Dreadnoughtus schrani. Here, we report the taxonomic composition of a site preserving thirteen isolated teeth and several osteoderms belonging to three dinosaur clades (Abelisauridae, Titanosauria, and Nodosauridae), and at least one clade of notosuchian crocodyliforms (Peirosauridae). They come from sediments positioned at the mid-section of the Cerro Fortaleza Formation, which is Campanian-Maastrichtian in age, adding valuable information to the abundance and biodiversity of this Cretaceous ecosystem. Since non-titanosaur dinosaur bones are almost absent in the locality, the teeth presented here provide a window onto the archosaur biodiversity of the Late Cretaceous in southern Patagonia. The nodosaurid tooth and small armor ossicles represent the first record of ankylosaurs for this stratigraphic unit. The peirosaurid material also represents the most austral record of the clade in South America.Fil: Paulina Carabajal, Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Barrios, Francisco. Provincia de Neuquén. Ministerio de Energía, Ambiente y Servicios Públicos. Dirección Provincial de Minería. Museo Provincial de Ciencias Naturales Prof. "Dr. Juan A. Olsacher"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Méndez, Ariel Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Cerda, Ignacio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Lee, Yuong Nam. Universidad Nacional de Seíl; Corea del Su

A new ankylosaurid skeleton from the Upper Cretaceous Baruungoyot Formation of Mongolia: its implications for ankylosaurid postcranial evolution

A new articulated postcranial specimen of an indeterminate ankylosaurid dinosaur from the Upper Cretaceous (middle-upper Campanian) Baruungoyot Formation from Hermiin Tsav, southern Gobi Desert, Mongolia includes twelve dorsal vertebrae, ribs, pectoral girdles, forelimbs, pelvic girdles, hind limbs, and free osteoderms. The new specimen shows that Asian ankylosaurids evolved rigid bodies with a decreased number of pedal phalanges. It also implies that there were at least two forms of fank armor within Ankylosauridae, one with spine-like osteoderms and the other with keeled rhomboidal osteoderms. Unique anatomical features related to digging are present in Ankylosauridae, such as dorsoventrally fattened and fusiform body shapes, extensively fused series of vertebrae, anteroposteriorly broadened dorsal ribs, a robust humerus with a well-developed deltopectoral crest, a short robust ulna with a well-developed olecranon process, a trowel-like manus, and decreased numbers of pedal phalanges. Although not fossorial, ankylosaurids were likely able to dig the substrate, taking advantage of it for self-defence and survival

The Early Cretaceous pterodactyloid pterosaur Coloborhynchus from North America

Volume: 37Start Page: 755End Page: 76