Lathrobium permutatum, Assing, 2009

Assing, V., 2009, New species and additional records of Lathrobium and Tetartopeus from the Palaearctic region (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 41 (2), pp. 1269-1283 : 1271-1272

Lathrobium permutatum nov.sp. ( Figs 1-6 )

T y p e m a t e r i a l: Holotype 3: " Transcanc. [sic], Georgia, Zchneti pr. Tbilisi, 800 m, 1.- 10.VI.1987, leg. Wrase /Schülke / Holotypus 3 Lathrobium permutatum det. V. Assing 2009 " (cAss) . Paratypes: 6 exs., same data as holotype ( OÖLL, cSch) ; 7 exs.: same data, but " 22.VI.1986 " (cSch, cAss) ; 2 exs.: same data, but " 1200 m, 26.VI.1986 (cSch); 2 exs.: same data, but " 1200 m, 5.VI.1987 (cSch) ; 21 exs.: "UDSSR - Transcauc. Georgia, Zchneti pr. Tbilisi, 800 m, 01.-10. Juni 1987, leg. Wrase /Schülke" ( MNHUB, cAss) ; 2 exs.: same locality, " 24.VI.1988, Wrase" (cSch, cAss) ; 4 exs.: same locality, " 20.VII.1985, leg. D.W. Wrase " (cSch, cAss) ; 1 ex.: " Transcauc. Georgia, Mzcheta pr. Tbilisi, VI.1986, leg. Wrase /Schülke (cSch); 1 ex.: same locality, " 16.VII.1985, leg. D.W. Wrase (cSch) ; 1 ex.: " Cauc. min. bor., Trialetskij Chreb., Borzhomi , 800 m, leg. Wrase / Schülke / 9.VII.1986 " (cSch) .

D e s c r i p t i o n: Body length 8.5-11.0 mm. Coloration: head, pronotum, and abdomen blackish, pronotum rarely and head exceptionally slightly paler dark-brown; elytra uniformly reddish, occasionally with the anterior margin indistinctly infuscate; legs and antennae reddish.

Head approximately as wide as long or weakly transverse; punctation coarse, rather dense in lateral and posterior portion of dorsal surface, with the interstices as wide as, or narrower than the diameter of the punctures, and sparse in median dorsal area; microsculpture very shallow and fine. Eyes approximately 1/4 the length of postocular region in dorsal view ( Fig. 1 ).

Pronotum 1.20-1.25 times as long as wide and 0.95-0.99 times as wide as head; punctation as coarse and usually as dense as that of head, but density subject to some intraspecific variation; interstices without microsculpture and shiny ( Fig. 1 ).

Elytra approximately 0.8 times as long as pronotum ( Fig. 1 ); punctation somewhat similar to that of pronotum, but usually shallower and less defined; interstices without distinct microsculpture.

Abdomen 1.0-1.1 times as wide as elytra; punctation fine and moderately dense; interstices with distinct fine microsculpture; posterior margin of tergite VII with palisade fringe.

3: sternite VII with weakly concave posterior margin, pubescence unmodified ( Fig. 3 ); sternite VIII with cluster of black modified setae in posterior median portion, posterior margin weakly excised in the middle ( Fig. 4 ); aedeagus with very long, acute, and sinuate ventral process ( Fig. 2 ).

♀: sternite VII 1.05-1.10 times as long as wide, in posterior median portion with very fine micropubescence, posterior margin truncate in the middle ( Figs 5-6 ); tergite IX undivided; tergite X approximately 0.7 times as long as tergite IX in the middle.

C o m p a r a t i v e n o t e s: Based on the male primary and secondary sexual characters, L. permutatum is very closely related to L. castaneipenne , with which it was previously confounded and from which it is distinguished by the longer and more distinctly sinuate ventral process of the aedeagus and by the usually uniformly reddish elytra (in L. castaneipenne anteriorly distinctly blackish). In L. permutatum , the ventral process (measured from the ventral angle to apex) is almost 0.7 times as long as the basal portion of the aedeagus (measured from the same angle to base) ( Fig. 2 ), whereas in L. castaneipenne the ventral process is little more than half as long as the basal portion ( Fig. 7 ). Whether these differences are an expression of interspecific, intersubspecific, or possibly even intraspecific variation can only be clarified when material from the southern Balkans and Turkey becomes available for study.

The type material of L. permutatum is here considered a distinct species rather than an extreme form of L. casteneipenne for several reasons. Firstly, the observed differences appear to be constant. Secondly, there are numerous other examples of highly similar sibling species, also with a similar aedeagal morphology in the genus. Thirdly, the aedeagus of Lathrobium species is generally subject to little intraspecific variation. Fourthly, the difference in the aedeagal morphology also coincides with a different coloration of the elytra. And finally, similar examples of extremely similar sibling species, with one species distributed in the Caucasus region (including Iran) and/or southernwestern Russia, are L. laevipenne HEER 1839 and L. impressifrons EPPELSHEIM 1884 ( ASSING 2007a), as well as L. crassipes MULSANT & REY 1878 and L. sareptae GREBENNIKOV 2001 ( GREBENNIKOV 2001).

E t y m o l o g y: The specific epithet (Latin, adjective: confused) refers to the fact that this species was previously confounded with L. castaneipenne .

D i s t r i b u t i o n: Lathrobium permutatum is currently known only from the environs of Tbilisi and Borzhomi, Georgia, but is probably more widespread. Previous records of L. castaneipenne from the Caucasus region and Iran (see notes in the section on L. castaneipenne ) may refer to this species.

Figures

Figs 1-8: Lathrobium permutatum nov.sp. (1-6) and L. castaneipenne KOLENATI (7-8): (1) forebody; (2, 7) aedeagus in lateral view; (3) male sternite VII; (4, 8) male sternite VIII; (5, 6) female sternite VIII. Scale bars: 1, 3-6, 8: 1.0 mm; 2, 7: 0.5 mm.