Hydraena (Hydraenopsis) grebennikovi, Hernando, Carles & Ribera, Ignacio, 2017

Hernando, Carles & Ribera, Ignacio, 2017, Two new terrestrial species of Hydraena Kugelann from the island of Bioko, Gulf of Guinea (Coleoptera: Hydraenidae), Zootaxa 4238 (2), pp. 281-286 : 284-285

Hydraena (Hydraenopsis) grebennikovi sp.n. ( Figs 2 , 5–6 )

Type locality. Forest in Pico Biao , Province of Bioko Sur, island of Bioko, Equatorial Guinea.

Type material. Holotype male ( NMW): "Eq. GUINEA, Bioko , // 0 3.3001, 0 0 8.6482, // 938m, 23.xii.2015, sift. // for. lit., V.Grebennikov "; " DNA voucher // IBE-AN525"; aedeagus dissected and mounted on a transparent card pinned with the specimen, plus red holotype label . DNA extraction stored in the IBE; COI with accession numbers LT707766 (COI-5', "barcode") and LT707763 (COI-3').

Paratypes. 2 males ( IBE, NMW) 1 female ( IBE): same data as holotype, with red paratype labels . Female paratype used for DNA extraction with voucher number IBE-AN577, mounted after extraction on a card (COI-3' accession number LT707764 ). One paratype male stored in absolute ethanol in the IBE.

Description. Length 1.35 mm (males), 1.54 mm (female paratype); width 0.60 mm (males), 0.70 mm (female paratype). External morphology very similar to H. bubi sp.n., with no clear consistent differences. In general males are slightly smaller, with straight middle and hind tibiae (similar to that of females) and a more griseous body colouration (more reddish in H. bubi sp.n.) ( Figs 1–2 ). Differences in surface sculpture, frontoclypeal suture or pronotum shape do not seem to be diagnostic and are difficult to systematise.

Sexual variation: Aedeagus ( Figs 5–6 ) with median lobe asymmetrical, with a double sinuation in ventral view; apex with digitiform expansions and a short, globular membranous apical piece; with two clearly visible dorsal setae. Left paramere short and stout (but longer than in H. bubi sp.n., and with longer and more robust setae); right paramere longer, with apex recurved over the median lobe. Middle and hind tibia of males straight, similar to that of females. Females with spermatheca and last abdominal segments similar to those of H. bubi sp.n. (see above).

Etymology. Named after our friend and colleague Vasily V. Grebennikov, who collected the specimens as part of a systematic research on the forest litter beetle fauna of Central African mountain systems.

Distribution. So far only known from the type locality.

Habitat and ecology. All specimens were in the same sample as the specimens of H. bubi sp.n. (see above).

Figures

FIGURES 1 & 2. Habitus of 1) Hydraena (Hydraenopsis) bubi sp. n., male paratype and 2) H. (Hydraenopsis) grebennikovi sp. n., female paratype (voucher No. IBE-AN 577, mounted after DNA extraction). Scale bar: 1 mm.

FIGURES 5 & 6. Aedeagus of Hydraena (Hydraenopsis) grebennikovi sp. n. (holotype) 5) lateral view, 6) ventral view. Scale bar = 0.1 mm.