Dicheirotrichus (Trichocellus) latimanus, Abak & D.W, 2006

Abak & D. W, 2006, Three new species of the subgenus Trichocellus GANGLBAUER 1891 of the genus Dicheirotrichus JACQUELIN DU VAL 1857 from the East Palaearctic, with description of the male of D. stenothorax (KABAK & KATAEV 1994) (Coleoptera, Carabidae), Linzer biologische Beiträge 38 (1), pp. 717-729 : 721-723

Dicheirotrichus (Trichocellus) latimanus spec. nova ( Figs 11-18 )

T y p e m a t e r i a l: Holotype: Russia: Khakassia, Tashtynskij Distr., Bolshoy On Valley, env. Bolshoy On vill., 21-24.VII.1998, A. Brinev leg. ( ZISP) . Paratypes: 2, 1, same data as holotype ( MPU, ZISP) ; 1, Kemerovo Prov., Tisul Distr., Gavrilovka , shore of mountain brook, 13.VII.1979, V. Eryshov leg. (cSHIL) ; 1, Altai, Gornoaltaiskaya AO, near Turochak, Snižek leg. (cWR) ; 2, Buryatia, Tunkinskie Goltsi, 30 km NNE of Turan, upp. of Shumak River , 1600- 1800 m, forest, 17.VIII.2000, A. Vorontsov leg. ( ISEAN) .

D e s c r i p t i o n: Body length 4.6-5.1 mm, width 1.8-2.1 mm.

Colour: Dorsum largely reddish brown, shiny. Head usually strongly infuscate, almost throughout black, or with bases of mandibles, apical margin of clypeus and lateral areas before and behind eyes pale. Pronotum with large central blurred transverse dark macula sometimes reaching lateral margins. Elytra rather strongly infuscate in apical two-thirds, with pale sutural intervals. Epipleurae of pronotum pale. Epipleurae of elytra infuscate anteriorly. Underside black. Appendages reddish brown but apical palpomeres, antennae from 4 th (sometimes from 3 rd or even 2 nd) antennomere, and metatarsi (sometimes also mesotarsi) distinctly infuscate. Pubescence yellow.

Head: Relatively large (WHmax/WP = 0.77-0.81; WHmin/WP = 0.59-0.62), with very coarse and dense puncturation areas under and particularly behind eyes, also on vertex, and with more fine puncturation around frontal foveae, sometimes also on frons and along apical margin of clypeus, but usually clypeus, central part of frons and anterior part of vertex unpunctured. Each puncture bearing a short seta. Eyes large, moderately or strongly convex, separated from buccal fissure by distance much lesser than width of first antennomere. Tempora rather short, convex. Clypeus depressed along apical margin. Labrum with nearly straight apical margin. Dorsal microsculpture in male usually not visible, in female (and rarely in male) obliterate isodiametric and weakly transverse meshes recognizable on clypeus and on areas behind eyes. Mandibles acute at apices. Antennae rather long, extending approximately to a quarter of elytra, with middle antennomeres about two times as long as wide.

Pronotum ( Fig. 11 ): Weakly convex, slightly flattened basally, 1.34-1.41 times as wide as long, widest in apical third, with sides basally more or less rectilinearly converging posteriad. Apical margin weakly arcuately emarginate, bordered only laterally. Basal margin nearly straight medially, clearly oblique laterally, with more or less distinct bead along oblique portion on each side, approximately equal to apical margin, notably narrower than elytral base, and ciliate on basal ridge. Apical angles not protruding anteriad, rounded at apices. Basal angles distinct, obtuse, usually with sharp apices, each bearing a moderately long seta. Lateral furrow narrow throughout and lateral depressions not developed. Basal foveae large and narrow, usually reaching basal pronotal margin and curved slightly to sides apically, separated from each other and in most cases also from sides by convexities; sometimes areas near basal angles slightly flattened. Pronotal surface rather coarsely and densely punctured along margins (punctures in basal foveae confluent) and more finely and sparsely on disc; central part of pronotum often almost unpunctured. Each puncture bearing a short seta. Dorsal microsculpture usually invisible, sometimes obliterate meshes recognizable at apical and basal angles.

Elytra: Moderately convex, elongated, 1.50-1.60 times as long as wide, 3.00-3.20 times as long and 1.40-1.49 times as wide as pronotum, weakly widened posteriad and broadly rounded at sides; widest behind middle. Humeri slightly prominent, evenly and rather broadly rounded at apices. Subapical sinuation weak. Sutural angle narrowly rounded at apex. Basal bead slightly sinuate, arcuately curving inside humerus up to lateral margin. Parascutellar setigerous pore puncture present, large. Third interval in apical third or just before with a discal setigerous pore near second stria. Posterior group of umbilicate series consisting of seven or eight setigerous pores. Striae unpunctured, slightly crenulate, weakly impressed on disc, superficial along elytral sides, particularly basally; 7 th stria obliterate at basal bead of elytra. Intervals rather flat, at most weakly convex in basal half, weakly narrowed posteriad. Puncturation of intervals on elytral disc somewhat coarse, with usually two (rarely one or three) punctures in a transverse row across each interval at middle. Each puncture bearing a short, posteriorly inclined seta. Microsculpture consisting of isodiametric meshes, in male clearly visible only in apical quarter, along basal bead and on 1-2 lateral intervals; in female evanescent meshes hardly recognized also on disc.

Wings: Fully developed.

Ventral surface: Metepisterna ( Fig. 14 ) markedly longer than wide, strongly narrowed posteriad. Anal sternum rounded at apex, with one pair of marginal setae in male and two pairs in female.

Legs: 5 th tarsomere with three pairs of ventro-lateral setae. Metatarsus comparatively stout, a little shorter than width of head across eyes, with almost triangular tarsomeres; 1 st metatarsomere much longer than second and slightly shorter than second and third together. In male protarsi ( Fig. 12 ) rather strongly dilated, with spongy vestiture ventrally; mesotarsi ( Fig. 17 ) distinctly, even if rather weakly, dilated and with biseriate vestiture ventrally (for comparison female mesotarsi - Fig. 18 ).

Female genitalia ( Fig. 13 ): Hemisternite asymmetrical, without spines or setae. Basal stylomere rather strongly widened apicad, also without spines or setae. Apical stylomere weakly arcuate, somewhat long, with a peg-like seta on outer ventral margin in basal third.

Median lobe of aedeagus ( Figs 15-16 ): Arcuate, with apex distinctly curved dorsad (lateral aspect), markedly dilated apically, its sides rather strongly sinuate just behind middle (dorsal aspect). Internal sac with asymmetrical pattern of tiny spines, without larger spines or teeth.

D i s t r i b u t i o n: This new species seems to be confined to the Altai-Sayan Mountain Land.

E t y m o l o g y: The species epithet is based on two Latin words, latus meaning ‘wide’ and manus meaning ‘hand’, referring to the dilated mesotarsi and strongly dilated protarsi, characteristic of the new species.

R e m a r k s: D. latimanus spec. nova is easily distinguished from all the other species of the genus by the mesotarsomeres 1-4 of males dilated and with adhesive vestiture ventrally. Another prominent distinctive feature of this new species is the median lobe of the aedeagus notably dilated apically. In all other species of Dicheirotrichus known to us, the male mesotarsi are simple (not dilated) and the median lobe of the aedeagus is much narrower apically. At the same time, D. latimanus spec. nova is very similar in other character states, including the shape of pronotum with distinct basal angles and the details of the internal sac of the median lobe, to D. angularis (REITTER 1899) from East Siberia; females of both species are difficult to separate. In addition to the two distinctive characters listed above, D. latimanus spec. nova may be distinguished from D. angularis by having the male protarsi more strongly dilated, the apical portion of the median lobe of the aedeagus clearly curved dorsad (the median lobe of D. angularis is illustrated in Figs 19-20), the pronotum relatively wider, the elytra slightly longer, and the elytral microsculpture more distinct and more widely distributed (in both sexes of D. angularis , meshes recognizable only apically). In our opinion, D. latimanus spec. nova and D. angularis seems to be two closely related and probably vicariant species. It is most likely also that the dilated male mesotarsi and the very wide apical portion of the apical lobe characteristic of D. latimanus spec. nova should be treated as autapomorphies evolved in this species after its separation from D. angularis .

Figures

Figs 11-18: Dicheirotrichus (Trichocellus) latimanus spec. nova. (11) Pronotum. (12) Male protarsus. (13) Hemisternite and stylus. (14) Left metepisternum. (15-16) Median lobe of aedeagus (holotype), (15) dorsal view, (16) lateral view. (17) Male mesotarsus. (18) Female mesotarsus. Figs 19-20: D. (T.) angularis (REITTER) (Amur Prov.). Median lobe of aedeagus, (19) dorsal view, (20) lateral view. Scales = 0.5 mm (A: Fig. 11; B: Figs 12, 14, 17, 18; C: Figs 13, 15-16, 19-20).