176-6 The Effects of Taphonomy on the Reconstruction of the Spatial Fossil Record of Terrestrial Mammals

Session: Laws of the Grave: Advances in Taphonomy Across the Paleontologic Record

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Authors:

Abstract:

The fossil record is widely recognized as a ‘natural laboratory’, that can be used to shed light on the ongoing biodiversity crisis if interrogated correctly. The fidelity of spatial data gleaned from the fossil record is crucial in this context, as scientists seek to evaluate correlates of extinction, especially geographic range size, and the spatial patterning of extinction events. Here we use a simulations-based framework as a means of testing this fidelity. We focus on patterns of spatial turnover – beta diversity – and the ability to detect extinction events that are selective for geographic range size. We simulate fossil records for 374 extant terrestrial mammal species from North America, employing a nested set of biotic and abiotic ‘filters’ that approximate known preservational biases, and which allow us to see where fidelity is lost. Our results indicate: a) that accurate detection of range size-extinction risk signals is sensitive to the inclusion of mammals with small body size; b) that false-positive signals of range size-selective extinction can be produced if extinction events are selective for body size; and c) that temporal trends in beta diversity are relatively robust to taphonomic bias. These results illustrate that our ability to reconstruct macroecological patterns over extinction events is governed by complex interactions between taphonomy, geographic range size, body size, and the locations of biogeographic hotspots. Although our results reinforce previous findings that the fidelity of the fossil record is better than anticipated, they also highlight potential biases – and the need for caution – when interpreting range size-extinction risk signals from terrestrial macrofossil records. Finally, we present ongoing experiments extending these simulations, modeling the frequency with which different parts of the mammalian skeleton are preserved, the number of phylogenetic characters associated with these elements, and thus the confidence with which we can recognize species. We show that, although these additional taphonomic filters reduce the potential fidelity of the fossil record, macroecological patterns can still be accurately reconstructed across a wide range of macroevolutionary scenarios (e.g., beta diversity that increases, decreases, or remains stable through time).

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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