Mediterranean conquerors: neotypification and phylogeography of the widely distributed earthworms "Aporrectodea trapezoides" and "Octodrilus complanatus" (Lumbricidae: Crassiclitellata)

Abstract

Cryptic lineages require identification and delimitation to guide their conservation and management. In the absence of type material that can be genotyped, designating a neotype becomes necessary: such is the case for Aporrectodea trapezoides and Octodrilus complanatus. These widely distributed earthworms are very common in Mediterranean habitats and harbour cryptic lineages. Specimens from the type locality (Jardin des Plantes, Montpellier) were genotyped to be included in species delimitation, phylogeographical, and phylogenetic analyses together with additional sequences from Mediterranean populations and close relatives. The Octodrilus complanatus neotype belonged to a clade inhabiting Spain, France, and Italy, with a putative origin in central Italy; two other species-level clades were restricted to northeastern Italy, Slovenia, and Croatia. The Aporrectodea trapezoides neotype clustered with a peregrine, Iberian, and Maghrebian specimens, together forming Aporrectodea trapezoides s.s. More restricted and accurate descriptions based on the neotypes and closely related specimens pointed out to the Eurosiberian lineage of Aporrectodea trapezoides s.l. corresponding to Aporrectodea borelii and provided a basis for the potential description of Octodrilus complanatus s.l. lineages. On top of the taxonomic advances, this work detected differences in their phylogeographical patterns (potentially connected to historical human dispersal) and provided an opportunity for more accurate ecological niche modelling.