The cave beetle genus Anthroherpon is polyphyletic; molecular phylogenetics and description of Graciliella n. gen. (Leiodidae, Leptodirini)

Abstract

The subtribe Anthroherponina form an iconic group of obligate cave beetles, typical representatives of the Dinaric subterranean fauna, which is considered to be the richest in the world. Phylogenetic studies within this subtribe are scarce and based only on morphological characters, which, due to troglomorphic convergence, are frequently unreliable. Moreover, morphological stasis and morphological polymorphism make classification of taxa difficult. To test if characters that have traditionally been accepted as informative for Anthroherponina classification are indeed reliable, we evaluated the monophyly of the most speciesrich genus of this subtribe - Anthroherpon Reitter, 1889. Our study, based on a molecular phylogenetic analysis of fragments of the 18S, 28S, and COI (both 5’ and 3’ end) loci revealed that the genus Anthroherpon as conventionally defined is polyphyletic. To resolve this polyphyly, we defined one new additional genus, Graciliella n. gen., for which we then examined the intrageneric diversity using molecular and morphometric approaches. Molecular phylogenetic analysis of two COI mitochondrial gene fragments revealed the presence of four species inside Graciliella n. gen., including two new species, which we here describe as G. kosovaci n. sp. and G. ozimeci n. sp. To analyze interspecific morphological differences within Graciliella we performed a discriminant analysis based on 40 linear morphometric measurements. The results showed that differences between species and subspecies inside Graciliella, however subtle they may seem, are measurable and reproducible. All species of the genus are briefly diagnosed, an identification key is proposed and a distribution map of all taxa of Graciliella is provided.