Micrillus hamatus, Assing, 2018

Assing, Volker, 2018, A revision of Palaearctic and Oriental Scymbalium and Micrillus III. New species, new combinations, and additional records (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 50 (2), pp. 977-996 : 985-986

Micrillus hamatus nov.sp. ( Figs 20-24 )

T y p e m a t e r i a l: Holotype ♂: " MOROCCO SE, 3.6.2007, Zagora 30 km SE, Zaouia-el- Barrahnia, Drâa riv., Lgt. F. Houška / Holotypus ♂ Micrillus hamatus sp. n., det. V. Assing 2018" (cAss).

E t y m o l o g y: The specific epithet (Latin, adjective: hooked) alludes to the shape of the apex of the aedeagus in lateral view.

D e s c r i p t i o n: Body length 7.0 mm; length of forebody 3.6 mm. Habitus as in Fig. 20 . Coloration: head blackish-brown with the anterior margin of the frons yellowishbrown; pronotum, elytra, and abdomen yellowish-red; legs yellowish; antennae yellowish-red.

Head 1.1 times as long as broad; punctation fine and moderately dense; median dorsal portion extensively impunctate; integument with extremely fine transverse microsculpture visible only at high magnification (100 x). Eyes weakly convex, not protruding from lateral contours of head, slightly shorter than postocular portion in dorsal view. Antennae slender; antennomere IV approximately twice as long as broad; antennomere X approximately 1.5 times as long as broad.

Pronotum 1.25 times as long as broad and as broad as head, of trapezoid shape, broadest at anterior angles and tapering posteriad; posterior margin weakly concave; punctation fine and moderately dense; midline impunctate; interstices without microsculpture.

Elytra nearly as long as pronotum; punctation very dense and very fine. Hind wings present. Protarsomeres I-IV undilated; metatarsomere I very long, slightly longer than the combined length of metatarsomeres II-IV.

Abdomen approximately as broad as elytra; punctation dense and fine; posterior margin of tergite VII with palisade fringe.

♂: sternite VIII ( Fig. 21 ) distinctly oblong, its posterior excision broadly and weakly concave; posterolateral processes of segment IX (valvulae) long and slender; aedeagus ( Figs 22-24 ) 0.95 mm long, symmetric, and weakly sclerotized; ventral process hookshaped in lateral view; internal sac with long dark membranous structure.

C o m p a r a t i v e n o t e s: Based on the long and slender valvulae IX and on the male primary and secondary characters, M. hamatus belongs to the M. testaceus group (see ASSING 2008, 2013). It is distinguished from all the species of this group by the conspicuously hook-shaped apex and the strongly sclerotized internal structures of the aedeagus. It is additionally distinguished from the three Micrillus species previously recorded from Morocco as follows:

from the widespread M. testaceus (ERICHSON, 1840) by the coloration, a less flat forebody, longer antennae with more oblong antennomeres IV-X, a more slender and more oblong pronotum, and longer elytra;

from M. scabrosus (FAUVEL, 1875) and M. tenuipennis ASSING, 2008 (both distributed in North Morocco) by a much paler and distinctly bicoloured body, a less flat forebody, a relatively smaller head, much larger eyes (strongly reduced in M. scabrosus and M. tenuipennis ), a posterior less strongly tapering pronotum, and much longer elytra.

For illustrations of M. testaceus , M. scabrosus , and M. tenuipennis see ASSING (2008).

D i s t r i b u t i o n: The type locality is situated to the southeast of Zagora, South Morocco, not far from the border with Algeria.

Figures

Figs 18-24: Micrillus virgatus (18-19) and M. hamatus (20-24): (18, 21) male sternite VIII; (19) basal portion of aedeagus in lateral view; (20) habitus; (22-23) aedeagus in lateral and in ventral view; (24) apex of ventral process in lateral view. Scale bars: 20: 1.0 mm; 18, 21-23: 0.5 mm; 19, 24: 0.1 mm.