Hydraena rosannae, Audisio & Trizzino & Biase & Mancini & Antonini, 2009

Audisio, Paolo, Trizzino, Marco, Biase, Alessio De, Mancini, Emiliano & Antonini, Gloria, 2009, A new species of Hydraena (Coleoptera: Hydraenidae) of the H. evanescens complex from Sardinia *, Zootaxa 2318, pp. 281-289 : 282

The Hydraena evanescens species-complex

The here morphologically defined Hydraena evanescens complex comprises three European species (including H. rosannae sp. nov. described below) sharing the following combination of characters:

· Body size small (1.8–2.2 mm), long and thin, uniformly reddish to yellowish ( Figs 1–2), with elytra long, only narrowly flattened at sides.

· Pronotum moderately transverse, about 1.15–1.18 times as wide as long ( Figs 1–2).

· Mid and posterior tibiae in males without teeth or distinct thorns, posterior tibiae in males only moderately dilated in their distal half ( Figs 1–2).

· Male genitalia with a rather small and short aedeagus, dilated in the middle in lateral view, with a very small and relatively simple distal mobile piece ( Figs 3–8), a very short and hardly visible flagellum, and with only a couple of small, almost obliterated pre-distal setae on the main piece.