Rodolfo A. García and Virginia Zurriaguz

            Dental histology of periodontal tissues (cementum, periodontal ligament and alveolar bone) has been studied in mammals, crocodylians and some basal tetrapods, but these structures have never been studied in titanosaur sauropods. The goal of this work was to study the structures of dental insertion in Titanosaurs. Like many physiological processes, histological analysis of titanosaur teeth shows hard tissue formation, characterized by a circadian rhythm. From thin sections it was possible to observe microstructures such as incremental lines of von Ebner, dentinal tubules and cross striations, all key to the understanding of developmental tooth dynamics. The structural and histological analyses carried out here on teeth of Late Cretaceous titanosaurs reveals the presence of acellular and cellular cementum, periodontal ligament, and alveolar bone, all structures necessary for a truly thecodont dentition. This is the first time documented for a dinosaur via histological tissue, and is an important finding that will help elucidate aspects of dinosaurian dentition, tooth replacement rate, feeding strategy, metabolism, and general biology.

García, R. A. and Zurriaguz, V. 2016. Histology of teeth and tooth attachment in titanosaurs (Dinosauria; Sauropoda) Cretaceous Research 57: 248-256.


            V. Zurriaguz
            Neuquensaurus is a small-sized titanosaur from the Upper Cretaceous of Patagonia, Argentina, for which two species were recognised in the past (Neuquensaurus australis and Neuquensaurus robustus). Given that such division was only based on the relative robustness of the limb bones, the validity of the species N. robustus has been questioned. In this work, we studied the morphological variation of the vertebrae of this genus through geometric morphometric techniques and the description of relevant anatomical features in order to assess if there are one or more morphotypes within Neuquensaurus. We found two distinguishable morphotypes, one belonging to N. australis and other that includes specimens assigned to both N. australis and N. robustus. The occurrence of a posterior cervical vertebra with a particular anatomical feature (i.e. four sprl) could indicate the presence of another taxon than N. australis in the studied sample. Although the validity of the species N. robustus cannot be discussed on the basis of the current data, our study supports the hypothesis of at least two different morphotypes of Neuquensaurus (which could be related to different taxa).

V. Zurriaguz (2015): Morphological diversity of Neuquensaurus Powell, 1992 (Sauropoda; Titanosauria): insights from geometric morphometrics applied to the vertebral centrum shape, Historical Biology: An International Journal of Paleobiology, DOI: 10.1080/08912963.2015.1079630


 La posibilidad futura de contar con un nuevo edificio para el MAU, ha generado el desarrollo de un proyecto que tiene como objetivo la confección de réplicas parciales de algunos ejemplares de la colección, para la actual exhibición, las cuales a su vez, servirán como prueba piloto para la construcción de réplicas completas.  Luego de haber experimentado y llevado a delante exitosamente la primer réplica en el MAU durante el 2012, de la pata delantera de uno de los dinosaurios titanosaurios, se ha encarado el primero de los proyectos, la realización a escala del brazo derecho de Megarraptor, un particular dinosaurio carnívoro que poseía brazos con enormes garras afiladas. Si bien este dinosaurio no pertenece a la colección del MAU, en las últimas salidas de campo se ha registrado el hallazgo de restos aislados de algunos ejemplares de este grupo en la zona de La Invernada. Algunas de las pruebas realizadas, utilizando las nuevas técnicas para la realización de réplicas, han arrojado resultados muy satisfactorios, por lo que la posibilidad de poder replicar los ejemplares para una exhibición futura, es muy probable. A pesar de que este ambicioso proyecto signifique un gran reto, el personal del MAU se encuentra trabajando en la búsqueda de nuevos materiales y la utilización de diferentes técnicas que resulten alternativas viables para poder desarrollarlo.

Oliver W. M. Rauhut, José L. Carballido, And Diego Pol

Late Jurassic dinosaur faunas from the Southern Hemisphere are still poorly known, and it thus remains unclear whether or not the famous Tendaguru fauna (Kimmeridgian–Tithonian, Tanzania) represents a typical Gondwanan dinosaur assemblage of that time. In South America, only the Oxfordian–Kimmeridgian Cañaadón Calcáreo Formation of Chubut Province, Argentina, has yielded more than isolated Late Jurassic dinosaur remains so far. Here we report fragmentary remains of a dipolodocid sauropod from this unit, representing the first record of this family from the Late Jurassic of South America. Incorporating the basal macronarian Tehuelchesaurus, an unidentified brachiosaurid, the dicraeosaurid Brachytrachelopan, and the diplodocid described here, the taxonomic composition of the sauropod fauna from the Cañadón Calcáreo Formation is remarkably similar to that of the Tendaguru Formation, but also to roughly contemporaneous faunas in North America and Europe. The diverse non-neosauropodan sauropod fauna known from the early Middle Jurassic (Aalenian–Bajocian) of the same depositional basin within Chubut Province is congruent with the dominance of non-neosauropodan sauropods in continental faunas globally to at least the Bathonian. These assemblages suggest a rapid faunal turnover within sauropod faunas in the late Middle Jurassic-earliest Late Jurassic at least in western Pangea, through which basal eusauropods were replaced by diplodocoid and macronarian neosauropods. Taking paleogeographical reconstructions into account, this faunal replacement might have taken place in a surprisingly short time interval of maximally five million years close to the end of the Middle Jurassic.

Oliver W. M. Rauhut, José L. Carballido & Diego Pol (2015) A diplodocid sauropod dinosaur from the Late Jurassic Cañadón Calcáreo Formation of Chubut, Argentina, Journal of Vertebrate Paleontology, 35:5, e982798, DOI: 10.1080/02724634.2015.982798

Lucio M. Ibiricu, Gabriel A. Casal, Rubén D. Martínez, Matthew C. Lamanna, Marcelo Luna And Leonardo Salgado

         Cretaceous outcrops in southern South America preserve a rich and evolutionarily important record of sauropod dinosaurs. Among Sauropoda, South American titanosaurs have garnered particular interest due to their abundance and taxonomic diversity. Nevertheless, the fossil record of rebbachisaurids has also improved significantly in recent years, and consequently so has knowledge of the group. However, many aspects of the anatomy and phylogenetic relationships of Rebbachisauridae remain unresolved, due in large part to the fragmentary nature of many members of the clade. Within this context, we describe new fossils of Katepensaurus goicoecheai Ibiricu, Casal, Martínez, Lamanna, Luna, and Salgado, a recently-named rebbachisaurid from the Upper Cretaceous (Cenomanian/Turonian) Bajo Barreal Formation of central Patagonia (Argentina). Based on these additional materials, we propose two new autapomorphies of this taxon: (1) ventral portion of posterior articular surface of anterior dorsal vertebral centrum wider than dorsal portion, conferring a ‘teardrop-shaped’ contour; and (2) ovoid fossa on dorsal aspect of anterior to middle dorsal vertebral transverse processes. These features enhance our understanding of morphological diversity within Rebbachisauridae and augment the diagnosis of Katepensaurus. Furthermore, phylogenetic analysis confirms the assignment of this taxon to the rebbachisaurid subclade Limaysaurinae. Katepensaurus is the southernmost record of a rebbachisaurid that is identifiable to the generic level.

Lucio M. Ibiricu, Gabriel A. Casal, Rubén D. Martínez, Matthew C. Lamanna, Marcelo Luna, and Leonardo Salgado (2015). New material of Katepensaurus goicoecheai (Sauropoda: Diplodocoidea) and its significance for the morphology and evolution of Rebbachisauridae. Ameghiniana 52: 430–446.


Ricardo N. Martínez, Cecilia Apaldetti, Gustavo Correa, Carina E. Colombi, Eliana Fernández, Paula Santi Malnis, Angel Praderio, Diego Abelín, Laura G. Benegas, Andrea Aguilar-Cameo And Oscar A. Alcober

The Quebrada del Barro Formation (QBF) is part of the continental Marayes-El Carrizal Basin, in NW Argentina. Here we report a diverse faunal assemblage recently discovered in the Quebrada del Barro Formation, along with a preliminary discussion of the taxonomic status and affinities of numerous vertebrate specimens found at two localities where this unit is exposed. The new vertebrate association includes remains of at least 12 different new species related to six major vertebrate groups: Cynodontia, Testudinata, Sphenodontia, Pseudosuchia, Pterosauria, and Dinosauromorpha. The most abundant specimens in this faunal assemblage are opisthodontian sphenodonts, tritheledontid cynodonts and basal sauropodomorph dinosaurs, but the assemblage also includes diagnostic remains of lagerpetid dinosauromorphs, theropods, pterosaurs, basal crocodylomorphs, and stem testudinatans. Several of these groups have also been reported for the Los Colorados Formation (LCF), although the two units differ in their taxonomic content at the species level and in the relative abundance of different taxonomic groups. A comparison of these two faunal assemblage suggest the fauna of QBF is younger than that of LCF and we tentatively assess a late Norian– Rhaetian age for the QBF. Some of the specimens reported here are known from well-preserved specimens and yield important new information for understanding the evolution of these groups, which underscores the relevance of the QBF fauna for assessing the dynamics of the major groups of vertebrates that dominated the terrestrial ecosystems during the early Mesozoic in Pangea.

Ricardo N. Martínez, Cecilia Apaldetti, Gustavo Correa, Carina E. Colombi, Eliana Fernández, Paula Santi Malnis, Angel Praderio, Diego Abelín, Laura G. Benegas, Andrea Aguilar-Cameo, and Oscar A. Alcober (2015). A new Late Triassic vertebrate assemblage from northwestern Argentina. Ameghiniana 52: 379–390.


El registro de dinosaurios terópodos identificados para la Formación Bajo de la Carpa (Santoniano, Cretácico Superior), corresponden a diversos restos de abelisauroideos (Velocisaurus unicus Bonaparte, una pelvis completa, una vértebra caudal y un nuevo espécimen casi completo recientemente descubierto), una tibia de un terópodo indeterminado, restos postcraneanos de un probable megaraptórido, alvarezsáuridos (Alvarezsaurus calvoi Bonaparte y Achillesaurus manazzonei Martinelli y Vera) y aves (Neuquenornis volans Chiappe y Calvo y Patagopteryx deferrariisi Alvarenga y Bonaparte). Aquí presentamos nuevos restos de dinosaurios carnívoros, recuperados a aproximadamente 100 m de la base de la unidad portadora y a unos 8 m por debajo del 58 contacto con la Fm. Anacleto (Campaniano inferior-medio), en depósitos de planicie de inundación fangosa, asociados a sistemas de canales fluviales de tipo anastomosado de carga mixta (areno-fangoso). Estos nuevos materiales corresponden a individuos de la familia Abelisauridae, e incluyen una fúrcula, un sacro y una pelvis incompleta, y un par de centros vertebrales dorsales, uno de ellos correspondiente a un ejemplar juvenil o subadulto. También se recuperaron dos restos vertebrales de un miembro del clado Megaraptora. La abundancia y diversidad de estos nuevos hallazgos refuerzan el concepto de que los abelisáuridos fueron el grupo dominante de depredadores, al menos en el norte de la Patagonia, pero que compartieron el tope de la cadena trófica con otros grupos de terópodos como los megaraptóridos.
XXIX Jornadas Argentinas de Paleontología de Vertebrados, Diamante, Entre Ríos 2015.


El neurocráneo del holotipo de Narambuenatitan palomoi Filippi, García y Garrido fue tomografiado permitiendo la reconstrucción virtual tridimensional del endocráneo y oído interno. Como en otros saurópodos, el endocráneo es bulboso anteroposteriormente corto, con una pituitaria bien desarrollada y proyectada posteroventralmente. Como en otros titanosaurios, los tractos y bulbos olfatorios son cortos y proyectados horizontalmente, el flocculus no está visible, el nervio craneano VI no penetra la fosa pituitaria y hay un solo canal para la salida del nervio craneano XII. Narambuenatitan se caracteriza por la presencia de una expansión dorsal bien desarrollada dorsalmente al mesencéfalo; una vena orbitocerebral diferenciada, y un canal mediano que comunica el piso de la cavidad endocraneana con la fosa pituitaria (arteria basilar?). Esta última está también presente en Bonatitan Martinelli y Forasiepi, y en el saurópodo basal Spinophorosaurus Remes et al. En el oído interno, el canal semicircular anterior es aproximadamente circular y levemente más grande que el canal semicircular posterior, que es sub-circular. El ángulo formado entre los canales anterior y posterior es de 90°. El canal semicircular lateral no es significativamente menor que el canal semicircular posterior. La lagena es simple, cónica y corta. En términos generales, la morfología endocraneana de Narambuenatitan se asemeja a la descrita para algunos titatnosaurios europeos. La nueva información sobre la morfología endocraneana y del oído interno en Narambuenatitan será de utilidad para aumentar el conocimiento de la paleoneurología del grupo, pero también para cotejar hipótesis en aspectos taxónómicos, filogenéticos y paleobiológicos.
XXIX Jornadas Argentinas de Paleontología de Vertebrados, Diamante, Entre Ríos 2015.