A review of Sisyphini Dung Beetles (Coleoptera: Scarabaeinae) endemic to Mauritius: insights from subfossil evidence and phylogenetic analysis

Abstract

Five indigenous species of Scarabaeinae are known from Mauritius island, classified into two genera: the monotypic Nesovinsonia Martinez & Pereira, 1958 and Nesosisyphus Vinson, 1946. This study conducts a taxonomic review of the latter genus Nesosisyphus, and evaluates its recent extinction using historical and new occurrence records, subfossils, and niche modeling. We provide the first molecular phylogeny and evaluate the evolutionary relationships of Nesosisyphus by comparing two different phylogenetic trees: the first, based on a Ultraconserved Elements (UCEs hereafter) dataset, and the second one, on three loci (28S, 16S, COI). We identify five Mauritian Nesosisyphus species, including a new extinct one, Nesosisyphus draco sp. n., from a 4,000 yr old subfossil. We diagnose, illustrate, and provide an updated key to all the sisyphine species from Mauritius, as well as the occurrence map. Our niche modeling analysis reveals a broader past distribution range for Mauritian sisyphines, now confined to small, disjunct forest patches due to extensive forest contraction and local extinctions.