Bolitogyrus signatus (Cameron, 1932)

Brunke, Adam J., 2017, A revision of the Oriental species of Bolitogyrus Chevrolat (Coleoptera, Staphylinidae, Staphylininae), ZooKeys 664, pp. 1-97 : 65-66

Bolitogyrus signatus (Cameron, 1932) Figs 2 H–I, 18 J–L, 20D (map)

Cyrtothorax signatus Cameron, 1932: 278.

Type locality.

Dikoya, Central Province, Sri Lanka.

Type material.

Cyrtothorax signatus Cameron, 1932.

Holotype (♂, BMNH): Type [circle label with red border] / Dikoya, 3,800-4,200 ft., 6.XII.81-16.I.82 [printed] / Ceylon, G. Lewis, 1910-320. [printed] / Cyrtothorax signatus Cam TYPE [written] / HOLOTYPE Cyrtothorax signatus Cameron, det. A. Brunke 2017 [red label] / AJB0000438 [identifier label].

Other material.

SRI LANKA: Sabaragamuwa: 'Sinharaja jungle’, in malaise trap, 10.IX.1979, M Kosztarab, T. Wijesinhe and L. Jayawickrema, 1 ♀, AJB0000579 (USNM).

Diagnosis.

Bolitogyrus signatus is easily recognized by the pronotum, which is widest at the anterior angles (Fig. 2H-I). This species (especially the male) bears a remarkable resemblance to the Neotropical species of the genus.

Redescription.

Measurements ♂ (n = 1): HW/HL 1.63; PW/PL 1.66; EW/ EL 1.23; ESut/PL 0.88; PW/HW 1.09; forebody length 5.1 mm.

Measurements ♀ (n = 1): HW/HL 1.55; PW/PL 1.21; EW/ EL 1.24; ESut/PL 0.71; PW/HW 0.97; forebody length 4.7 mm.

Coloration: body dark; head, pronotum and abdomen entirely dark, elytra dark, each with yellow v-shaped marking; antennomere 1 yellow with darkened apex, 2-5 reddish-orange with darkened apices, 6-10 dark brown, 11 pale yellow; palpi yellowish with apical segment darkened; forecoxae yellow with basal fifth dark brown in both sexes, legs yellow, forefemur with dorsal surface dark brown, lateral face and dorsal surface of mid and hind tibia with subapical dark marking, tibia with lateral face darker.

Head strongly transverse, more so in male; dorsal surface including frons glossy with sparse, small and poorly impressed punctures; in male, lateral part of head beneath eye expanded ventrad. Antennomeres 8-10 distinctly transverse but not asymmetrical.

Pronotum transverse and widest at anterior angles, strikingly more strongly transverse in males than females, with lateral portions explanate in males, protuberance moderate (male) or distinct (female); medial part of disc almost entirely without micropunctures, anterior angles with many impressed micropunctures. Elytra slightly transverse, suture distinctly to slightly shorter than pronotum at middle, nearly all punctures of epipleuron setose.

Abdomen with disc of tergites III-VI distinctly impunctate.

Median lobe in lateral view evenly converging to apex, ventral face nearly straight except for very apex flexed ventrad, without teeth (Fig. 18K); median lobe in parameral view slightly dilated to apical fourth, spoon-shaped with slightly acuminate apex (Fig. 18J); paramere distinctly longer than median lobe, dilated about midlength and weakly narrowed to elongate, parallel apical portion with truncate apex (Fig. 18L); paramere entire but with median suture to almost midlength, peg setae with thin marginal group, peg setae also scattered to each side of the midline (Fig. 18L); male sternite VIII with shallow but distinct emargination and triangular glabrous area medi ally; male sternite IX moderately expanded at midlength, with distinct emargination, partly fused to laterotergal sclerites at midlength.

Female with tergite VIII bearing large, circular emargination (Fig. 2I), tergite X shield-shaped with raised area elongate trapezoidal and without depression, apex truncate with acutely projected middle; gonocoxae with bases fused medially.

Distribution.

Figure 20D. Likely endemic to Sri Lanka.

Bionomics.

Specimens were collected in September and December-January at 1160-1280 m. One specimen was collected by a malaise trap.

Comments.

Bolitogyrus signatus is the only Oriental species of the genus to exhibit strong sexual dimorphism, as in some Neotropical species. The sclerites of the male and female genital segments are uniquely fused in this species.