26-3 Identifying Sources of Bias in Modern Avian Preservation in the Paraguayan Chaco and their Implications for Future Fossil Interpretations

Session: Interdisciplinary Paleontology: New approaches to solving complex paleontological problems (Posters)

Presenting Author:

Authors:

Abstract:

Previous research on preservation of avian remains has identified many sources of bias, leading to a very poorly resolved fossil record. Studies of disparity and richness have found that even relatively weak biases in preservation transform our interpretation of the fossil record, emphasizing the importance of understanding sources of preservation bias. The aim of this study is to quantify that imbalance between living communities and the fossil record, and investigate characteristics that may be the cause of such differences. The modern avian remain assemblage along the Pilcomayo Megafan is used in this study because the environments represented along the fan more closely resemble the bulk of the rock record than many more studied tributary river systems, providing a better modern analog with which to interpret the fossil record. Over the course of four years, we have studied 476 vertebrate localities along the Pilcomayo Megafan and have recorded various taphonomic, sedimentological, and ecological data from each. Preliminary analyses of the avian subset of these data, specifically minimum animal unit calculations, have revealed an underrepresentation of vertebral column elements and ribs, with an overrepresentation of appendicular and skull elements. Both bone density and predator preference have been implicated to cause similar biases in mammal assemblages, the influence of these factors will be investigated using multiple regression analysis to provide comparative data for bird remains. Bone density will be quantified for a range of taxa that encompass both the size and ecological diversity of the living community of the study area, with predator preference assessments based on nutrient availability, utility of anatomical parts, and scavenging patterns. Additionally, a comparison between the living community (either from existing data or captured from camera traps) and re-constructed dead community will be made to identify broader ecological or taxonomic biases. An understanding of biases in modern avian bone preservation allows for paleontologists a clearer window into the lives of these charismatic but fragile dinosaurs in the geologic past. 

Geological Society of America Abstracts with Programs. Vol. 58, No. 4, 2026

doi: 10.1130/abs/2026RM-14640

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