Browsing by Autor "Fernando E. Novas"

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A New Snake Skull from the Paleocene of Bolivia Sheds Light on the Evolution of Macrostomatans
(Public Library of Science, 2013) Agustín Scanferla; Hussam Zaher; Fernando E. Novas; Christian de Muizon; Ricardo Céspedes
Macrostomatan snakes, one of the most diverse extant clades of squamates, display an impressive arsenal of cranial features to consume a vast array of preys. In the absence of indisputable fossil representatives of this clade with well-preserved skulls, the mode and timing of these extraordinary morphological novelties remain obscure. Here, we report the discovery of Kataria anisodonta n. gen. n. sp., a macrostomatan snake recovered in the Early Palaeocene locality of Tiupampa, Bolivia. The holotype consists of a partial, minute skull that exhibits a combination of booid and caenophidian characters, being the presence of an anisodont dentition and diastema in the maxilla the most distinctive trait. Phylogenetic analysis places Kataria basal to the Caenophidia+Tropidophiidae, and represents along with bolyeriids a distinctive clade of derived macrostomatans. The discovery of Kataria highlights the morphological diversity in the maxilla among derived macrostomatans, demonstrating the relevance of maxillary transformations in the evolution of this clade. Kataria represents the oldest macrostomatan skull recovered, revealing that the diversification of macrostomatans was well under way in early Tertiary times. This record also reinforces the importance of Gondwanan territories in the history of snakes, not only in the origin of the entire group but also in the evolution of ingroup clades.
Bizarre notosuchian crocodyliform with associated eggs from the Upper Cretaceous of Bolivia
(Taylor & Francis, 2009) Fernando E. Novas; Diego F. Pais; Diego Pol; Ismar de Souza Carvalho; Agustín Scanferla; Álvaro Mones; Mario Súarez Riglos
Discovery of several, almost complete skeletons of a new notosuchian taxon constitutes the most important body-fossil discovery for the Mesozoic of Bolivia, adding substantially to the meager record of this region of South America. At least two partially disarticulated skeletons and two complete eggs were found together in a small area, constituting one of the few available associations of skeletal remains and eggs for extinct crocodyliforms. In this paper we describe this material as a new genus and species. We consider only the skull morphology, because most of available postcranial remains are still under technical preparation.
The postcranial anatomy of <i>Yacarerani boliviensis</i> and the phylogenetic significance of the notosuchian postcranial skeleton
(Taylor & Francis, 2015) Juan Leardi; Diego Pol; Fernando E. Novas; Mario Súarez Riglos
In this contribution, we describe new specimens of Yacarerani boliviensis from the Cajones Formation (Upper Cretaceous) of Bolivia. We focus on the postcranial anatomy of Y. boliviensis, because this anatomical region is completely unknown in other sphagesaurid notosuchians up to the present. At least eight individuals representing almost the entire postcranial skeleton are described. Although the postcranial anatomy of Yacarerani resembles that of other notosuchians in many features, five autapomorphic characters were identified: pedicles of the atlas bearing a lateral bulge; absence of rounded depressions on the dorsal surface of the anterior to middle dorsal vertebrae; coracoid bearing an oblique crest on its lateral surface; lateromedially compressed anterior ungual phalanges; and femur with a shallow depression for the M. puboischiofemoralis internus 1 and M. caudifemoralis longus. Observed variation in the postcranial anatomy of basal mesoeucrocodylians was incorporated as new characters in a phylogenetic analysis, expanding the postcranial information used in current phylogenetic data sets. The phylogenetic analysis depicts Yacarerani forming a clade with Adamantinasuchus, which is positioned at the base of Sphagesauridae. This family is well nested among a clade of ’advanced notosuchians,’ and Mariliasuchus is recovered as its sister group. The cladistic analysis recovered new postcranial synapomorphies for Notosuchia and less inclusive clades, although the fact that many taxa lack postcranial remains limits the number of unambiguous postcranial synapomorphies within Notosuchia.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Leardi, J. M., D. Pol, F. E. Novas, and M. Suarez Riglos. 2015. The postcranial anatomy of Yacarerani boliviensis and the phylogenetic significance of the notosuchian postcranial skeleton. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2014.995187.