Pseudolathra transversicollis, Assing, 2012

Assing, V., 2012, The Pseudolathra species of the East Palaearctic and the Oriental regions (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 62, pp. 299-330 : 322-324

Pseudolathra transversicollis sp. n. ( Figs 52-58 , Map 3 )

Type material:

Holotype ♂: “W. Thailand: 300 m., Thung Yai Wildlife Sanctuary , 15°28'N - 98°48'E / Tak Province, Umphang District , Song Bae Stream . 18-27.iv.1988. / Evergreen rain forest. M.J.D. Brendell. B.M. 1088-183 / Flight interception trap / Holotypus ♂ Pseudolathra transversicollis sp. n., det. V. Assing 2012“ ( BMNH) . Paratypes: 11 ♂♂, 4 ♀♀: same data as holotype ( BMNH, cAss) ; 2 ♂♂: “ Haldwani Dist. , Kumaon, India. H.G.C. / H.G. Champion coll. B.M. 1927-409“ ( BMNH, cAss) .

Etymology:

The specific epithet (Latin, adjective) refers to the usually transverse pronotum.

Description:

Large species: body length 9.0- 10.5 mm; length of forebody 4.5-5.0 mm. Coloration: head and pronotum black, with the posterior and often also the anterior margins diffusely dark-reddish; elytra reddish to reddish-brown, posteriorly often weakly and diffusely infuscate; abdomen black, with the posterior and lateral margins of the tergites reddish; legs dark-yellowish; antennae reddish.

Head ( Fig. 52 ) strongly transverse, approximately 1.2 times as wide as long; posterior angles obtusely marked; dorsal surface conspicuously glossy, almost impunctate, except for the sparse micropunctation and for a few coarse macropunctures near eyes and near posterior margin. Eyes large and bulging, approximately 3 times as long as postocular region in dorsal view. Antenna approximately 3.2-3.5 mm long; antennomeres III-X with very narrow bases, distinctly dilated apically.

Pronotum ( Fig. 52 ) usually weakly transverse, 1.00-1.05 times as broad as long and slightly wider than head; dorsal series composed of usually 5-6 coarse punctures; lateral portions with very sparse coarse punctures; surface glossy and with sparse micropunctation.

Elytra ( Fig. 53 ) nearly as long as pronotum; laterally with fine and complete submarginal carina; punctation arranged in three series, one along suture, one in the middle, and one near lateral margin; interstices with micropunctation and glossy. Hind wings fully developed. Protarsomeres without appreciable sexual dimorphism, in both sexes strongly dilated.

Abdomen distinctly narrower than elytra; punctation moderately coarse and dense on tergite III, gradually becoming finer and less dense on tergites IV-VII; interstices with shallow microsculpture, but glossy; posterior margin of tergite VII with palisade fringe.

♂: sternite VII with distinctly concave posterior margin ( Fig. 57 ); sternite VIII oblong, posterior excision narrow and deep, its depth approximately 2/5 the length of sternite ( Fig. 58 ); aedeagus large, 1.4-1.5 mm long, with short ventral process with apex of triangular shape and subapically with two minute teeth (lateral view) ( Figs 53-56 ).

Intraspecific variation:

Slight differences between the males from Thailand and those from northern India were observed in the morphology of the aedeagus (see Figs 53-54 and Figs 55-56 , respectively). However, the two specimens from northern India were collected almost a century ago and the apical parts of the aedeagus are somewhat (semi-)membranous, so that the observed differences may be based on artefacts. Moreover , the distance between Thailand and northern India is considerable, which would account for some clinal variation, and the differences between the aedeagi of different species are usually rather pronounced. Therefore, in the absence of additional morphological evidence, the observed differences are attributed to intra- rather than interspecific variation. More material, particularly from northern India, is needed to clarify if the observed differences are constant.

Comparative notes:

Pseudolathra transversicollis is distinguished from all other Palaearctic and Oriental congeners by larger size, the distinctive coloration, the usually slightly transverse pronotum, the shape of the male sternite VII, and by the shape of the aedeagus. Based on the similarly derived morphology of the aedeagus and similar external characters, P. transversicollis is undoubtedly most closely related to P. nigerrima , apparently its adelphotaxon. From this species, it is additionally separated by the different shape and chaetotaxy of the male sternite VII.

Distribution and natural history:

At present, P. transversicollis is known from one locality in Uttaranchal, northern India, and one locality in western Thailand, where the specimens were collected with flight interception traps in an evergreen rain forest at an altitude of 300 m.

Figures

Map 3: Distributions of Pseudolathra pulchella (triangles; open triangles: female-based records), P. vellicans (filled circles), P. transversicollis (open squares), based on revised records.

Figs 52-58: Pseudolathra transversicollis from Thailand (52-54) and northern India (55-58): forebody (52); aedeagus in lateral and in ventral view (53-56); male sternite VII (57); male sternite VIII (58). Scale bars: 52: 1.0 mm; 53-58: 0.5 mm.