Omalium rhodicum ZANETTI & ASSING, 2013

Assing, V., 2013, On the Staphylinidae of Rhodes, Greece (Insecta Coleoptera), Linzer biologische Beiträge 45 (2), pp. 1587-1613 : 1600-1604

Omalium rhodicum ZANETTI & ASSING nov.sp. ( Figs 24-29 )

T y p e m a t e r i a l: Holotype: " GREECE - Rhodos [14], 4 km SW Embonas, Attaviros, 36°12'16''N, 27°51'54''E, 1030 m, 22.III.2013, V. Assing / Omalium rhodicum Zanetti & Assing, 2013 / Holotypus " (cAss).

E t y m o l o g y: The name (adjective) is derived from Rhodos, the Latin name of the island where the species was discovered.

D e s c r i p t i o n: Habitus as in Fig. 24 . Measurements of holotype: body length (with extended abdomen) 4.3 mm; head width 0.64 mm; head length from clypeus to neck 0.44 mm; width of pronotum 0.81 mm; length of pronotum 0.61 mm; length of

elytra from humeral angles to apex 1.11 mm; width of elytra 1.11 mm; length from anterior margin of clypeus to posterior margin of elytra 2.33 mm.

Coloration: head blackish-brown; pronotum dark-brown, slightly paler than head, with posterior margin and posterior two thirds of lateral margins yellowish-brown; elytra brown with a yellowish area near humeral angles extending posteriad almost to middle of lateral margin; abdomen brown, posterior margin of tergite VII and apical third of tergite VIII yellowish; antennae with antennomere I brown with yellowish apex, II and III yellowish, partially brown, IV yellowish, V yellowish-brown, and VI-XI brown; mouthparts yellowish, with apical maxillary palpomere somewhat darkened at apex; legs entirely yellowish.

Head ( Fig. 25 ) transverse (HW/HL: 1.45); temporal angles somewhat rounded; clypeus with obsolete microsculpture and almost impunctate; remainder of dorsal surface of head with irregular punctation; punctation sparser anteriorly, denser on vertex and between ocelli; subantennal impressions wide and deep, with dense punctation, laterally delimited by two arched elevations; ante-ocellar pits deep and wide; ocelli distinct, yellowish, separated by a distance shorter than that between ocellum and eye; neck densely punctured and with weak microsculpture. Eyes large, much longer than temples, prominent, without infraorbital carina. Antenna gradually incrassate; antennomere I elongated and oval; II ovoid; III twice as long as wide; IV-V subquadrate; VI-X of increasing width and increasingly transverse; X nearly twice as wide as long; XI longer than broad and conical in apical half.

Pronotum ( Fig. 25 ) transverse (PW/PW: 1.3) and 1.3 times as broad as head, widest in anterior half; anterior angles very obtuse, but not entirely rounded; hind angles marked, obtuse; punctation moderately dense; interstices somewhat wider than diameter of punctures, without microsculpture; pair of discal impressions deep, somewhat arched, closest in the middle of pronotum; lateral margins with large depressions near posterior angles.

Elytra ( Fig. 25 ) 1.8 times as long (measured from humeral angles) and 1.4 times as broad as pronotum; punctation moderately coarse, tending to form irregular striae in discal area, weakly confluent near postero-lateral angles; interstices without microsculpture. Legs with spines on the external side in distal two thirds and distal half of the meso- and metatibia, respectively.

: aedeagus as in Figs 26-29.

C o m p a r a t i v e n o t e s: Omalium rhodicum belongs to a group of three closely related species, which are mainly distributed in islands of the Mediterranean see. This group includes O. doderoi ZANETTI 1980 (Sardinia) , O. espanoli JARRIGE 1952 (Majorca) , and O. henroti COIFFAIT 1976 ( Cyprus, southern Turkey) ( ZANETTI 1980); the latter species was reported from southern Turkey (Mersin) based on a female by ASSING (2006f). Both O. espanoli and O. doderoi were collected in caves, whereas O. henroti has been sifted from leaf litter of forests at altitudes of 1060-1250 m ( ASSING 2006f; ASSING & WUNDERLE 2001). The habitus of these species is similar to that of O. rivulare (PAYKULL 1789) , which is why they are included in the rivulare group in ZANETTI (1987, 2002). The only characters distinguishing them from O. rhodicum are the finer punctation, the coloration of the elytra, and the shape of the aedeagus. In O. henroti and O. espanoli , the elytra are yellowish, each with a brown apical spot of triangular shape. In O. doderoi , they are yellowish-brown, paler near the humeral angles, diffusely darkened in distal half, the dark coloration reaching the suture, but not the posterior margin and the postero-lateral angles. The general morphology of the aedeagus of the species allied to O. henroti (male sexual characters of O. espanoli unknown) is distinctive, with a long and slender, apically more or less enlarged median median lobe (see ZANETTI 1980). The median lobe of O. rhodicum is similar to that of O. henroti , but distinctly more slender. The aedeagus of a male of O. henroti from Cyprus is illustrated in Figs 30-33.

C o m m e n t: The female recorded as O. rivulare from a beach near Monolithos, Rhodes, by SCHEERPELTZ (1961) may belong to O. rhodicum , but it seems more likely that it refers to O. riparium impar MULSANT & REY 1861 . The specimen was looked for, but not found, in the Scheerpeltz collection at the NHMW.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: Theholotypewascollectedin the Attaviros by sifting litter and grass roots in a pasture with scattered old Quercus ilex at an altitude of 1030 m, together with 134 specimens of O. rugatum MULSANT & REY 1880 .

Figures

Figs 24-33: Omalium rhodicum nov.sp. (24-29) and O. henroti COIFFAIT from Cyprus (30-33): (24) habitus; (25) forebody; (26-27, 30-31) aedeagus in lateral and in ventral view; (28-29, 32-33) apical portion of median lobe of aedeagus in lateral and in ventral view. Scale bars: 24: 1.0 mm; 25: 0.5 mm; 26-27, 30-31: 0.2 mm; 28-29, 32-33: 0.1 mm.