Onthophagus pilauco sp. nov. (Coleoptera, Scarabaeidae): evidence of beetle extinction in the Pleistocene-Holocene transition in Chilean Northern Patagonia.

Francisco Tello,José R. Verdú,Mario Zunino,Michele Rossini

doi:10.3897/zookeys.1043.61706

Francisco Tello, José R. Verdú + Show 2 more

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https://doi.org/10.3897/zookeys.1043.61706

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Abstract

The South American Pleistocene–Holocene transition has been characterized by drastic climatic and diversity changes. These rapid changes induced one of the largest and most recent extinctions in the megafauna at the continental scale. However, examples of the extinction of small animals (e.g., insects) are scarce, and the underlying causes of the extinction have been little studied. In this work, a new extinct dung beetle species is described from a late Pleistocene sequence (~15.2 k cal yr BP) at the paleoarcheological site Pilauco, Chilean Northern Patagonia. Based on morphological characters, this fossil is considered to belong to the genus Onthophagus Latreille, 1802 and named Onthophagus pilaucosp. nov. We carried out a comprehensive revision of related groups, and we analyzed the possible mechanism of diversification and extinction of this new species. We hypothesize that Onthophagus pilaucosp. nov. diversified as a member of the osculatii species-complex following migration processes related to the Great American Biotic Interchange (~3 Ma). The extinction of O. pilaucosp. nov. may be related to massive defaunation and climatic changes recorded in the Plesitocene-Holocene transition (12.8 k cal yr BP). This finding is the first record of this genus in Chile, and provides new evidence to support the collateral-extinction hypothesis related to the defaunation.

Highlights

The South American Pleistocene–Holocene transition (~16.0–11.0 k cal yr BP) has been characterized by drastic changes in climatic conditions, animal and plant diversity, and types of early-human occupation (Dillehay 1989; Borrero et al 1998; Dillehay et al 2015)
The fossil remains found at Pilauco correspond to a new and extinct species of the genus Onthophagus, closely related to the hircus group
This record brings new evidence of beetle extinction related to the Pleistocene–Holocene transition and massive defaunation after a possible cosmic impact and/ or YD cooling reversal events

Summary

Introduction

The South American Pleistocene–Holocene transition (~16.0–11.0 k cal yr BP) has been characterized by drastic changes in climatic conditions, animal and plant diversity, and types of early-human occupation (Dillehay 1989; Borrero et al 1998; Dillehay et al 2015). The latest hypothesis is based on stochastic changes induced by cosmic impact (i.e., the Younger Dryas bolide-impact hypothesis, ~12.8 k cal yr BP), which resulted in large fires that contributed to a rapid overturn in species, and climatic and environmental conditions in both hemispheres (Firestone et al 2007). This assumption is supported by evidence of extraterrestrial material and charcoal spherules, which have been found at several paleontological sites distributed across four continents (e.g., Pino et al 2019; Wolbach et al 2020). Cobboldia russanovi Grunin, 1973 (Gasterophilidae) was a mammoth-botfly that became extinct at the end of the Pleistocene in Russia due to the loss of its host (Kuzmina and Korotyaev 2019, and references therein)

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