New discoveries from the jurassic of patagonia: insights into the early history of frogs.

NICOLI, L.; BÁEZ, A.M:

Neuquén

Congreso; II Congreso Latino-Americano de Paleontología de Vertebrados.; 2008

Universidad Nacional del Comahue

 Remains of frogs are remarkably abundant in the Jurassic of Patagonia, especially considering the scarce pre-Cretaceous records of the anuran lineage from most parts of the world. In addition to the nearly complete specimens of Vieraella herbsti and Notobatrachus degiustoi from the Liassic Roca Blanca and Middle-Late Jurassic La Matilde formations of Santa Cruz Province (Báez and Basso, 1998 and literature cited therein; Báez and Nicoli, 2004), partial remains that represent a new species of Notobatrachus, N. reigi (Báez and Nicoli, 2008), have been discovered recently in the Callovian-Oxfordian Cañadón Asfalto Formation of central Chubut Province. Also, isolated bones preserved as impressions on complementary slabs from the latter stratigraphic unit have morphological features that might be interpreted as suggesting the presence of another taxon. In order to assess the phylogenetic relationships of the putative new taxa and in view that several hypotheses for the taxonomic position of Notobatrachus and Vieraella have been proposed (Stipanicic and Reig, 1957; Estes and Reig, 1973; Báez and Basso, 1998; Roček, 2000; Gao and Wang, 2001; Gao and Chen, 2004), a parsimony analysis based on osteological characters was performed. Extant as well as extinct members of the anuran and caudatan lineages and several Paleozoic fossil taxa that were proposed as close relatives of all, or some, of the living amphibians were included. The analysis supports a basal position for the Patagonian taxa, outside the node that unites the extant anurans.