New abelisaurid skeletal remains from La Invernada (Bajo de la Carpa Formation, Santonian), northwestern Patagonia, Argentina

The La invernada fossil area (Bajo de la Carpa Formation, Santonian) has provided abundant dinosaur remains, which are mainly represented by titanosauriform sauropods and abelisaurid theropods. The latter include Viavenator exxoni and other partial skeletons. Recently a new abelisaurid specimen (MAu-Pv-Li-665) was found in La invernada, which consists of three vertebrae (anterior cervical, cervico-dorsal and dorsal) and cervical and dorsal ribs, found closely associated.Fil: Gianechini, Federico Abel. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Departamento de Bioquímica y Ciencias Biológicas. Área de Zoología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; 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: Filippi, Leonardo Sebastián. Gobierno de la Provincia del Neuquén. Municipalidad de Rincón de Los Sauces. Secretaria de Turismo y Patrimonio. Museo Municipal Argentino Urquiza; ArgentinaFil: Juarez Valieri, Ruben Dario. Gobierno de la Provincia de Río Negro. Ministerio de Turismo, Cultura y Deporte. Secretaría de Cultura; Argentina1º Reunión Virtual de Comunicaciones de la Asociación Paleontológica ArgentinaBuenos AiresArgentinaAsociación Paleontológica Argentin

A new and well-preserved early-diverging abelisaurid (theropoda: ceratosauria: abelisauroidea) from the early late cretaceous of northern patagonia

Abelisaurid theropods were the most diverse and abundant medium-sized to large-bodied carnivorous dinosaurs in many Gondwanan and European paleoecosystems during the Late Cretaceous, frequently occupying the apex predator niche in these environments. Although several derived abelisaurids (e.g., the Patagonian brachyrostrans Ekrixinatosaurus novasi, Skorpiovenator bustingorryi, Viavenator exxoni, Aucasaurus garridoi, and Carnotaurus sastrei and the Madagascan majungasaurine Majungasaurus crenatissimus) are represented by well-preserved skeletons, earlier-diverging members of the clade (e.g., the African Kryptops palaios and Rugops primus) are known from much less complete material. Consequently, the early evolutionary history of Abelisauridae remains poorly understood. Here we report a new taxon of medium-sized (body length ~5 m) basal abelisaurid collected from an exposure of the lowermost Upper Cretaceous (Cenomanian) Candeleros Formation in an area known as Aguada Pichana near the town of Añelo in Neuquén Province, northern Patagonia, Argentina. The new form is known from two individuals, one of which is represented by a largely complete, partially articulated skeleton (including much of an articulated skull and multiple teeth plus dorsal, sacral, and caudal vertebrae, dorsal ribs, hemal arches, a scapula, the forelimb lacking the manus, the pelvis, and several hind limb elements); the second individual is known only from a partial skull (consisting of the maxilla, lacrimal, jugal, quadratojugal, quadrate, pterygoid, ectopterygoid, palatine, and dentary with teeth). Notable osteological features include: (1) maxilla with 14 tooth positions (as in Carnotaurus and some generically unidentified abelisaurids but 3–5 fewer than in Rugops, Skorpiovenator, and Majungasaurus); (2) lacrimal with prominent anterior process; (3) postorbital with ‘inflated’ dorsal terminus and suborbital flange; (4) anterior caudal transverse processes with well-developed anterior projection at distal end; (5) humerus and metatarsals proportionally slender, recalling those of non-abelisaurid abelisauroids; and (6) radius and ulna ~34% length of humerus (proportionally longer than in Aucasaurus, Carnotaurus, and Majungasaurus). Phylogenetic analysis using two independent datasets recovers the new Candeleros form as a basal (i.e., non-brachyrostran, nonmajungasaurine) abelisaurid. As such, the new taxon is herein regarded as the earliest-branching abelisaurid that is known from the greater part of the skeleton.Fil: Lamanna, Matthew. Carnegie Museum Of Natural History; Estados UnidosFil: Porfiri, Juan Domingo. Universidad Nacional del Comahue; ArgentinaFil: Dos Santos, Domenica. Universidad Nacional del Comahue; ArgentinaFil: Juarez Valieri, Ruben Dario. Universidad Nacional del Comahue; ArgentinaFil: Gandossi, Paolo. Progetto Argendino, Bergamo; ItaliaFil: Baiano, Mattia Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo "Carmen Funes"; Argentina79th Annual Meeting of Society of Vertebrate PaleontologyBrisbaneAustraliaSociety of Vertebrate Paleontolog

Theropods from the La Bonita site, Bajo de la Carpa Formation (Neuquén Group, Santonian), Río Negro, Argentina: analysis of dental evidence

The abundant record of theropods from Bajo de La Carpa Formation (Neuquén Group, Santonian), known from the end of the nineteenth century, come from numerous locations within the Neuquén Basin. During the excavation of the titanosaur Bonitasaura salgadoi at the La Bonita fossiliferous site, northwest of Río Negro province Argentina, were recovered three isolated teeth assignable to non-avian theropod dinosaurs. Previous studies of these dental materials suggested that MPCA-Pv-247 corresponds to an indeterminate tetanure possibly related to Orkoraptor, a taxon of uncertain phylogenetic position at that moment, and MPCA-Pv-249 and 251 as possible abelisauroids. Three methods were carried out, namely, a cladistic analysis performed on a dentition-based data matrix, and a discriminant and cluster analyses performed in a large dataset including measurements of non-avian theropod teeth. The results assign for the first time a confidently phylogenetic position to the described dental material. The analysis shows that MPCA-Pv 247 belongs to Megaraptoridae, whereas MPCA-Pv 249 and 251 were recovered as belonging to Abelisauridae, supporting in a reliable way the previous assignments. The results show the presence of Megaraptoridae at La Bonita and, additionally, they represent an evidence of the first direct association of megaraptorids and abelisaurids at the same locality of the Bajo de La Carpa Formation, according to similar associations from other units of the Neuquén Group.Fil: Meso, Jorge Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Gianechini, Federico Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto Multidisciplinario de Investigaciones Biológicas de San Luis; ArgentinaFil: Juarez Valieri, Ruben Dario. Gobierno de la Provincia de Río Negro. Ministerio de Turismo, Cultura y Deporte. Secretaría de Cultura; ArgentinaFil: Apesteguía, Sebastián. Fundación de Historia Natural Félix de Azara; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Da Silva Correa, Samuel Aparecido. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentin