A case of allopatric speciation in the Central System (Iberian Peninsula): Leistus elpis sp. nov., a sibling species of Leistus constrictus (Coleoptera, Carabidae)

Abstract

The aim of this work was to demonstrate that the Leistus (Leistus) constrictus Schaufuss 1862 populations from Sierra de Aylln belong to a new sibling species of the true L. (L.) constrictus from Sierra de Guadarrama. We describe Leistus (Leistus) elpis sp. nov. The species were separated by the study of external morphology of qualitative characters, especially male genitalia, and quantitative characters (morphometric analysis). In L. (L.) constrictus the apical lamina of the aedeagus appears to be a long gutter flanked by lateral ridges with an open truncation in its anterior part; in L. (L.) elpis sp. nov. the apical lamina is completely ridged, even in the anterior part, forming a kind of labial thickening, enclosing the median lobe, and giving the apex a clearly closed and pointed outline. It is not possible, or very difficult, to distinguish between females of L. (L.) constrictus and females of L. (L.) elpis sp. nov., based on their external anatomy as they are practically identical. The female genitalia do not offer taxonomic information for discriminating between the species using the genital armour or the structure of the spermathecal complex. However, subtle differences were found through morphometric analysis, as well as for males of both species. Field surveys suggest that the pass Puerto de Somosierra is the geographical barrier that has led to this allopatric speciation.