Morphological reply to a DNA call: a new cryptic species of Hydraena from western Europe, with a complete overview of the Hydraena gracilis complex (Coleoptera: Hydraenidae: “Haenydra” lineage)

Abstract

Recent molecular analyses revealed unexpected genetic variability within Hydraena gracilis, one of the most common and widespread European moss beetles, belonging to the West Palaearctic endemic “Haenydra” lineage. For this taxon, molecular data univocally evidenced two distinct clades, the first one including populations from the Iberian Peninsula, and the second including populations from central and eastern Europe. Aedeagal morphology of H. gracilis was further investigated, finally demonstrating the actual existence of a new cryptic species of the H. gracilis complex in Portugal, Spain and the French Pyrenees. The geographical range of the true H. gracilis was consequently revised. Finally, dichotomous keys for males of all species belonging to the H. gracilis complex, and for males of all the Iberian “Haenydra” species, are also supplied.

Keywords:

• “Haenydra”
• Hydraena gracilis complex
• new taxon
• Iberian Peninsula
• France

Acknowledgements

We are grateful to Dr. Ignacio Ribera (IBE, Barcelona, Spain), who first suggested to us the presence of the new species, in the light of molecular data. We are indebted to Dr. Manfred Jäch (NMW) for confirming the validity of the new species and for valuable comments and suggestions. Thanks are also due to Dr. Pierfilippo Cerretti (CNBF, Verona, Italy) for female elytral photographs and to Alejandra Morán (Universidad de León) for the geographical map of the new species. A visit of the first author to the NMW was supported by Synthesys (Application AT–TAF–53).