The first stygobiont species of Coleoptera from Portugal, with a molecular phylogeny of the Siettitia group of genera (Dytiscidae, Hydroporinae, Hydroporini, Siettitiina)

Abstract

Iberoporuspluto sp. n., the first stygobiont beetle from Portugal (Dytiscidae, Hydroporinae), is described from a single female from the cave Soprador do Carvalho (Coimbra). The species is highly troglomorphic, depigmented, blind, and with elongated appendages not adapted for swimming. A molecular phylogeny based on a combination of three mitochondrial and two nuclear genes showed the new species to be sister to I.cermenius Castro & Delgado, 2001 from Córdoba (south of Spain), within the subtribe Siettitiina of the tribe Hydroporini. Both species are included in a clade with Siettitiaavenionensis Guignot, 1925 (south of France) and Rhithrodytesagnus Foster, 1992 and R.argaensis Fery & Bilton, 1996 (north of Portugal), in turn sister to the rest of species of genus Rhithrodytes Bameul, 1989, in what is here considered the Siettitia group of genera. We resolve the paraphyly of Rhithrodytes by transferring the two Portuguese species to Iberoporus Castro & Delgado, 2001, I.agnus (Foster, 1992), comb. n. and I.argaensis (Fery & Bilton, 1996), comb. n.

Molecular work was partly funded by projects CGL2013-48950-C2-1-P and CGL2016-76705-P (AEI/FEDER, UE) to IR. ASR is supported by a research grant (15471) from VILLUM FONDEN. The holotype was collected under permits of the Instituto de Conservação da Natureza e das Florestas.