Systematic Zoology

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Ph.D. Thesis

"Phylogenie der Nacktschneckengattung Limax (Limacidae, Pulmonata)"

Phylogeny of the terrestrial slug genus Limax (Limacidae, Pulmonata)

The terrestrial slug genus Limax is distributed mainly in Europe (and introduced worldwide) and includes 20 to 30 currently accepted species, which are usually (often poorly) defined by external morphology and genital characters, a phylogeny is entirely lacking.

A new dataset has now been generated from the mitochondrial gene cytochrome oxidase subunit I (COI). The preliminary phylogenetic results give a first impression of relationships in this genus. To date, more than 250 specimens of Limax and other Limacidae are included in the molecular dataset, with a geographic range covering central Europe.

Initial tree reconstructions show that the genus Limax seems to be a monophlyletic clade. Limax itself splits into multiple groups. Each of these groups contains at least one species, often several species, already defined by morphological characters. The represented groups include species that are widely distributed in Europe such as Limax maximus and Limax cinereoniger, each of which is part of a monophyletic group of possibly more than one species. Alternately, the tree includes radiations of rare species, such as a clade of 6-8 species that is endemic to Corsica. Many of these species are not yet formally described.

These findings indicate that COI-sequences are mostly suitable for the problem, but also the need for wider biogeographic and taxonomic sampling. Species of Limax from eastern Europe are currently poorly represented in the tree, but appear to diverge basally within the genus. The inclusion of more of these species may give additional insights into the phylogeography of Limax. Furthermore, it would be beneficial to increase the number of other limacid genera in the analysis. Finally, future work will confirm and refine the preliminary results on the basis of sequencing further genes (for example ITS1 and 2, 16S rRNA and 28S rRNA) and AFLP-fingerprinting.