Pseudomedon pallidus ( FAUVEL 1902)

Assing, V., 2009, On the Pseudomedon species of the Palaearctic region (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 41 (2), pp. 1175-1189 : 1183-1184

Pseudomedon pallidus ( FAUVEL 1902) ( Figs 10-13 ; Map 2)

Euphonus pallidus FAUVEL 1902: 182 .

T y p e m a t e r i a l e x a m i n e d Lectotype ♀ [slightly damaged]: "Bordj men aïl [=Bordj Menaïl], Kabylie / pallidus Fvl. / Ex-Typis / Lectotype / Lectotypus Euphonus pallidus Fauvel , rev. V. Assing 2009 / Pseudomedon pallidus (Fauvel) det. V. Assing 2009" ( IRSNB).

C o m m e n t: The original description of Euphonus pallidus is based on two syntypes from "Bordj-Men-Aïl" and " Djelfa " ( FAUVEL 1902). One of these type specimens, a female, was located in the Fauvel collection at the IRSNB. In referring to this specimen as "le type", COIFFAIT (1984) designated it as the lectotype.

Pseudomedon pallidus is the type species of the genus group name Euphonus FAUVEL 1902, which according to FAUVEL (1902) and COIFFAIT (1984) is distinguished from the subgenus Pseudomedon by the presence of a superficial, more or less distinct median furrow or shiny median line of the pronotum, the more or less distinctly reduced pigmentation, smaller eyes, more slender antennae, and the more or less distinctly visible tentoria. However, the presence or absence of a distinct (shiny or impressed) midline is subject to pronounced intrageneric – and sometimes intraspecific – variation in Medonina. Also, the reductions of pigmentation and eye size, as well as the relative length of the antennae and the legs are adapations to the probably endogean habitat. And finally, the visibility of the tentoria (darkish spots) is due to the reduced pigmentation. As has been suspected earlier ( ASSING 2008b) and as is now confirmed based on an examination of the type species of Euphonus, the characters distinguishing Euphonus from Pseudomedon are variable, a result of an adaptation to an endogean habitat, not discreet, and most unlikely to be synapomorphic, suggesting that Euphonus is an artificial taxon. Based on the male sexual characters, P. huetheri HUBENTHAL 1927 was already moved from Euphonus to Pseudomedon by ASSING (2008b). There is no evidence whatsoever that the species still in Euphonus on the one hand and the species currently in Pseudomedon should constitute monophyletic groups, so that Euphonus is placed in synonymy with Pseudomedon .

D i a g n o s i s: Similar in size and general appearance ( Fig. 10 ) to the brachypterous morph of P. obscurellus and particularly to P. dido . Body length: 3.4 mm. Coloration of whole body almost uniformly yellowish.

Head distinctly dilated behind eyes ( Fig. 11 ). Eyes of reduced size, approximately as large as antennomere I in cross-section ( Fig. 13 ), approximately 0.3 times as long as postocular region in dorsal view. Antenna slender ( Fig. 12 ); antennomere III approximately 2.5 times as long as wide; IV-VI twice as long as wide; VII 1.5 times as long as wide; VIII-X weakly oblong. Elytra 0.97 times as long as pronotum.

C o m p a r a t i v e n o t e s: This species is readily distinguished from all its congeners by the smaller eyes, from P. obscurellus additionally by the more slender antennae, and from P. huetheri by smaller size.

D i s t r i b u t i o n: This evidently extremely rare species is currently known only from the type locality in Algeria (Map 2).

Map 2: Distributions of Pseudomedon pallidus (FAUVEL) (filled circle), P. mirei COIFFAIT (open circles), P. chobauti COIFFAIT (filled square), and P. lecoqi COIFFAIT (open square).

Figures

Figs 10-19: Pseudomedon pallidus (FAUVEL), lectotype (10-13), P. mirei COIFFAIT, holotype (14), P. lecoqi COIFFAIT, paratype (15-17), P. obscurellus (ERICHSON) (18), and P. obsoletus (NORDMANN) (19): (10, 15) habitus; (11, 14, 16) forebody; (12) antenna; (13) head in lateral view); (17) head and pronotum in lateral view; (18) male sternite VIII; (19) posterior portion of male sternite VIII. Scale bars: 10, 15: 1.0 mm; 11-14, 16-17: 0.5 mm; 18-19: 0.2 mm.