Evidence of bacterial decay and early diagenesis in a partially-articulated tetrapod from the Triassic Chañares Formation.

HERNÁNDEZ DEL PINO SANTIAGO; MANCUSO ADRIANA; PREVITERA ELENA; BENAVENTE CECILIA; PREVITERA ELENA; HERNÁNDEZ DEL PINO SANTIAGO; BENAVENTE CECILIA; MANCUSO ADRIANA

PALAIOS

SEPM-SOC SEDIMENTARY GEOLOGY

Lugar: Lawrence; Año: 2017 vol. 32 p. 367 - 381

0883-1351

The vertebrate fauna of the lower Carnian Chañares Formation of Argentina is dominated by the well-preserved small- and medium-bodied archosauriforms and therapsids. Here we report the discovery of a non-mammalian therapsid dicynodont (of greater than 20 cm skull length) that was found partially-articulated within the floodplain deposit. Taphonomic analysis of this specimen reveals details of its paleobiology and taphonomic history, including: the cause of death, exposure to predation and/or scavenging, subsequent subaerial decay, and final entombment. The specimen studied also allowed for the documentation of the activity of micro-organisms involved in decay processes during the biostratinomic stage (soft tissue decomposition on surface) and diagenetic stages (anaerobic decay). Our results indicate that, despite bones being found in concretions, the formation of calcareous concretions is not a necessary requirement for bone preservation. Consequently, this study highlights the funtion of volcanic ash in promoting bone preservation.