Acta Palaeontologica Polonica

A glimpse at the ontogeny of the fossil neobatrachian frog Calyptocephalella canqueli from the Deseadan (Oligocene) of Patagonia, Argentina

Paula Muzzopappa and Laura Nicoli

Acta Palaeontologica Polonica 55 (4), 2010: 645-654 doi: http://dx.doi.org/10.4202/app.2009.0093

Two fossil tadpoles collected in the Deseadan levels (Oligocene) at the Scarritt Pocket locality of central Patagonia are studied herein. These specimens, which show different degrees of skeletal development, have been assigned to the neobatrachian Calyptocephalella canqueli based on the morphology of the frontoparietals and the presence of adult specimens of this fossil species at the same locality. The concurrent analysis of three developmental stages (Gosner Stages 35/36 and 38/39, and adult) has provided significant data about the ontogeny of this species, including the change of the pattern of exostosis of the frontoparietals, from a pitted to a tuberculated pattern, and the corroboration of the inclusion of two neural arches in the formation of the urostyle. This evidence will shed light on developmental mechanisms that might be involved in the evolution of the genus Callyptocephalella.

Key words: Anura, Neobatrachia, Australobatrachia, Calyptocephalella, osteogenesis, Cenozoic, Oligocene, Patagonia.

Paula Muzzopappa [paula@gl.fcen.uba.ar], CONICET, Laboratorio de Paleontología Evolutiva de Vertebrados. Departamento de Ciencias Geológicas, Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Pabellón II, Ciudad Universitaria (C1428EHA). Ciudad Autónoma de Buenos Aires, Argentina; Laura Nicoli [lnicoli@macn.gov.ar], CONICET, División Herpetología. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. Av. Angel Gallardo 470 (C1405DJR). Ciudad Autónoma de Buenos Aires, Argentina.