Recurrent diversification patterns and taxonomic complexity in morphologically conservative ancient lineages of Pimelia (Coleoptera: Tenebrionidae)

Abstract

AbstractThe genus Pimelia Fabricius is the most speciose in the tribe Pimeliini (Coleoptera: Tenebrionidae). It consists of approximately 320 species distributed mainly in xeric environments in the western Palaearctic region and northern deserts in the Afrotropical region. Pimelia is a very heterogenous group despite its conserved morphology. Based on two mitochondrial (cox1 and 16S) and five nuclear markers (ITS1, ITS2, 18S, Wg and H3), we carried out a phylogenetic and biogeographic study to: (i) provide a comprehensive phylogenetic hypothesis for the relationships within Pimelia; (ii) re‐evaluate the taxonomic status and organization of clades (subgenera) within the genus; and (iii) establish a temporal framework and historical scenario for the evolution and diversification of Pimelia in the western Mediterranean Region. Pimelia presents a high degree of morphological conservatism and possibly stasis, often resulting in complexes of cryptic species. Repetitive patterns of variation are found recurrently between and within groups, which resulted in a conundrum of nonmonophyletic taxonomic assemblages based on morphological homoplastic characters. Based on our results, we propose a new taxonomic arrangement for Pimelia with 14 clades, treated as subgenera, with the description of six new subgenera: Iberomelia subgen.n., Italomelia subgen.n., Magrebmelia subgen.n., Hispanomelia subgen.n., Massadraamelia subgen.n. and Amblypteraca subgen.n. Our results also indicate an Oligocene (Rupelian) origin for Pimelia, and North Africa as the most likely area of origin. The complex geological and climatic history in the western Mediterranean region has shaped the distribution and diversity of species in the area. The current faunal assemblages observed in Pimelia are the result of complex patterns of recurrent processes of dispersal and vicariance, including in situ diversification through time in different areas of the Mediterranean basin. Pimelia is a fascinating yet very challenging group, and the phylogenetic and systematic framework developed here will pave the way for further ecological, taxonomic, and evolutionary studies at local and regional scales.This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub:DCA003F7‐85F4‐4803‐A859‐5738C6473151.