El Museo Argentino de Ciencias Naturales Bernardino Rivadavia, cumplió 199 años y los festejó con el montaje en la exhibición de un nuevo dinosaurio: Bonatitan reigi. Analía Forasiepi, investigadora del Conicet, en el Museo de Historia Natural de San Rafael, Mendoza, contó que este nuevo ejemplar, que ahora puede verse en el museo de Parque Centenario, se halló junto con otros vertebrados que se recuperaron en el norte de Patagonia, mas precisamente en Río Negro, en 2004, junto al paleontólogo Agustín Martinelli. Entre los especímenes que se encontraron en la región figuran ciertos peces pulmonados, anuros (anfibios que en su estado adulto carecen de cola), tortugas Chelidae y serpientes. Bautizado en honor de su descubridor, el Dr. José Bonaparte, considerado el padre de la paleontología argentina, el Bonatitan está encuadrado entre los titanosaurios.  "La reconstrucción de este nuevo dinosaurio enriquece el patrimonio del Museo de Argentino de Ciencias Naturales y es un orgullo para la paleontología nacional, que está creciendo sin cesar desde los tiempos de Florentino Ameghino".

Fuente y foto: Diario La Nación

Horacio Parent, Ryszard Myczyn´ski , Armin Scherzinger and Günter Schweigert
The new genus Cieneguiticeras, assigned to the family Oppeliidae, is described on the basis of Andean lower-middle Tithonian ammonites from Arroyo Cieneguita, west-central part of the Neuquén-Mendoza Basin, Argentina. The macroconchs are closely homoeomorphic with Neochetoceras Spath and the microconchs have a ‘glochiceratid’-type morphology. The stratigraphic range of Cieneguiticeras nov. gen. includes the lower and middle Tithonian by means of a succession of two or three species which are interpreted as members of a phyletic lineage. Ammonites from the Tithonian of Cuba, Mexico and France are more or less confidently included in this new genus.

 Parent, H., Myczyn´ski, R., Scherzinger, A. and Schweigert, G. 2010. Cieneguiticeras, a new genus of Tithonian oppeliids (Ammonoidea, Late Jurassic). Geobios 43 (2010) 453463.

Braincases of Abelisaurid theropods

Ariana Paulina Carabajal
The braincases of the abelisaurid theropod dinosaurs Abelisaurus comahuensis and Aucasaurus garridoi are described and compared. These two taxa share the presence of a floccular recess that is ‘8’-shaped, the absence of a medullar eminence in the floor of the endocranial cavity and the possession of a well-developed, narrow and tall dorsal longitudinal sinus. The basisphenoidal recess is continuous dorsocaudally with two pneumatic cavities, which are separated medially by a thin septum. A connection between the metotic canal and the columellar recess that probably represents the exit of cranial nerve IX is observed in Abelisaurus. Aucasaurus has a skull roof with a wide sagittal crest and a low parietal eminence that differentiates it from other derived abelisaurids such as Abelisaurus, Carnotaurus and Majungasaurus. The abelisaurid braincases described herein show strong consistency in their general morphology and structure. However, there is some variation, and these detailed descriptions are important for understanding the variation and distribution of braincase characters within Abelisauridae.

Carabajal A. P., 2011.Braincases of Abelisaurid theropods from the Upper Cretaceous of North Patagonia. Paleontology, 1-14. doi: 10.1111/j.1475-4983.2011.01055.x.

Federico A. Gianechini, Peter J. Makovicky, and Sebastián Apesteguía.

The Unenlagiinae is a clade of Gondwanan dromaeosaurid theropods mainly known from incomplete skeletal material. The group includes two recently discovered theropods, Buitreraptor and Austroraptor, from which cranial remains are available with in situ maxillary and dentary teeth, thus allowing the study of tooth morphology. Among the derived traits that diagnose the dentition of unenlagiines are: (i) high tooth count, (ii) small size of individual teeth when compared with skull height, (iii) absence of denticles and carinae, and (iv) presence of longitudinal grooves on the tooth crown. This suite of dental characteristics, shared between Buitreraptor and Austroraptor, can be considered as diagnostic of the Unenlagiinae or, at least, a more exclusive clade within the group. The teeth of Buitreraptor exhibit a remarkable labiolingual compression, whereas Austroraptor possesses more conical teeth, probably respective autapomorphic features. On one hand, these dental morphologies differ from those observed in most Laurasian dromaeosaurids and, for instance, could be considered as further proof of the purported vicariant evolution of the lineage on the southern continents. On the other hand, the morphological similarities (e.g., absence of denticles) between the teeth of unenlagiines and other theropod lineages, including Mesozoic birds and ornithomimosaurs, can be considered as the result of parallel trends related to dental reduction.

Gianechini, F.A., Makovicky, P.J., and Apesteguía, S. 2011. The teeth of the unenlagiine theropod Buitreraptor from the Cretaceous of Patagonia, Argentina, and the unusual dentition of the Gondwanan dromaeosaurids. Acta Palaeontologica Polonica 56 (2): 279–290.