2 Interdisciplinary Paleontology: New approaches to solving complex paleontological problems (Part I)

Paleontology is increasingly drawing upon insight from other disciplines to solve complex problems and generate more accurate reconstructions of past life. This session will illustrate novel interdisciplinary research and provide tools to develop such approaches.

Monday, 18 May 2026
8:00 AM - 12:00 PM
Alvarado F

Fossils on Fans: Taphonomy and Paleoecology in Megafan Settings with Insights from the Pilcomayo Megafan, Paraguay

Paper number: 2-0
Program: Technical Sessions
Time: 8:00 AM – 8:20 AM

Authors

Abstract

It appears that megafan deposition dominates modern sedimentary basins, therefore understanding preservation and ecology in such aggradational sedimentological settings is key to understanding the temporal, spatial, and compositional fidelity of terrestrial fossil assemblages, among other paleoecologically important variables. Most modern taphonomic studies that have focused on degradative settings, so run the risk of misrepresenting the bulk of the rock record. Our research group has a four-year time series of taphonomic data from the world’s largest megafan: the Pilcomayo Fan, which starts in Bolivia and currently deposits along a ~250km length of the Paraguay-Argentina border. We are using these data to build a model to understand preservational bias in megafan settings and hence better characterise terrestrial paleoecology.

We have surveyed the vertebrate assemblages accruing in one locality proximal to the Pilcomayo Fan apex (Pozo Hondo) and one distal (General Diaz). These localities were broken into six subenvironments (exposure surface, channel, levee, floodplain, avulsion lobe, and avulsion flood apron) that should capture the range of environments from aggradational settings that are identifiable in the rock record. 476 localities representing bone, integument, eggshell, and track localities have been surveyed, with each locality revisited on all subsequent field seasons providing key time-series data of bone degradation. Furthermore we have found the first evidence of several taphonomic modes that are common in the rock record that have not been reported from the modern before, and our field area in the depositional zone of the Pilcomayo (General Diaz) has shown deposition of >1m of sediment over two years, burying articulated megafaunal remains.

Overall patterns of taphonomic modification seen in Paraguay mirror many of those in the rock record, albeit with several notable distinctions, particularly when parsing data by subenvironment. Bones on the surface weather at a constant rate, faster than observed in some other studies, but do not seem to abrade. Actively depositing environments show less weathered assemblages, and higher frequencies of burial. In general, spatial fidelity seems to be high and several observations indicate that temporal fidelity may also be high, which is promising for the use of the paleontological record to address ecological questions.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410542

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