Stilicoderus separandus, Assing, 2013

Assing, V., 2013, Three new species and new records of Stilicoderus and Stiliderus (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 45 (2), pp. 1571-1585 : 1578-1580

Stilicoderus separandus nov.sp. ( Figs 9-13 , Map 3 )

Stiliderus strigosus: ROUGEMONT 1985: 219 ff.; partim.

Type material: Holotype: " India: Meghalaya #3b, West Garo Hills dist., Trail Tura - Tura Peak summit, 900 m, 15.X.2004, 25°30'13''N, 90°14'18''E / Leg. G. Cuccodoro, C. Carlton, R. Leschen & D. Erne / Holotypus Stilicoderus separandus sp.n. det. V. Assing 2013" ( MHNG). Paratypes: 5 exs.: same data as holotype ( MHNG, cAss) ; 6 exs.: same data as holotype, but "#2b... 800 m, 14.X.2004, 25°30'12''N, 90°14'07''E " ( MHNG, cAss) ; 1 ex.: same data as before, but "#6... 18.X.2004 " ( cAss) ; 1 ex.: same data as before, but "#2a... 650 m, 14.X.2004, 25°30'28''N, 90°13'54''E " ( MHNG) ; 5 exs.: same data as holotype, but "#5b,..., Tura Peak, near summit, 1200 m, 17.X.2004, 25°30'16''N, 90°14'38''E " ( MHNG, cAss) ; 9 exs.: same data, but "#5a... Mt Nokrek National Park , 1200 m, 17.X.2004, 25°30'02N, 90°14'54''E " ( MHNG, cAss) ; 1 ex.: " India: Meghalaya #1, Ri Bhoi dist., near Nongpoh , 600 m, 12.X.2004, 25°55'31''N, 91°52'25''E / Leg. G. Cuccodoro, C. Carlton, R. Leschen & D. Erne " ( cAss) ; 6 exs.: " India: Meghalaya #12a-c, East Khasi Hills dist., Cherrapunjee, below Mawmluh , 1200 m, 24.X.2004, 25°14'59''N, 91°41'52''E / Leg. G. Cuccodoro, C. Carlton, R. Leschen & D. Erne " ( MHNG, cAss) ; 1 ex. [teneral]: " India: Assam #14c, North Cachar Hills dist., road Mahur-Maibang , Sanhaju , 850 m, 26.X.2004, 25°12'25''N, 93°07'28''E / Leg. G. Cuccodoro, C. Carlton, R. Leschen & D. Erne " ( MHNG) ; 4 exs.: " India: Assam #15b, North Cachar Hills dist., Road Umrangso-Gunjong , 900 m, 27.X.2004, 25°24'41''N, 92°49'28''E, / Leg. G. Cuccodoro, C. Carlton, R. Leschen & D. Erne " ( MHNG, cAss) .

Additional paratypes: material of S. strigosus from Meghalaya listed in ROUGEMONT (1985).

Etymology: The specific epithet is the gerundivum of the Latin verb separare and means "to be separated". It alludes to the previous confusion of this species with S. strigosus .

Description: Body length 5.8-7.0 mm; length of forebody 3.4-3.8 mm. Body flattened; habitus as in Fig. 9 . Coloration variable: head and pronotum blackish-brown to black; elytra dark-reddish, with the scutellar region, the suture, the lateral and posterior margins more or less extensively and more or less distinctly infuscate, reddish coloration often confined to a weakly defined median spot; abdomen reddish-brown to blackishbrown; legs reddish to blackish-brown; antennae brown to dark-brown.

Head ( Fig. 10 ) distinctly transverse, approximately 1.15 times as broad as long, widest across eyes, and of subrectangular shape; posterior angles rounded, but noticeable; punctation moderately coarse and very dense; interstices reduced to narrow ridges, without microsculpture. Eyes large and strongly convex, approximately half as long as postocular region between posterior margin of eye and posterior constriction. Antenna slender, approximately 2.0 mm long, preapical antennomeres approximately as long as broad.

Pronotum ( Fig. 10 ) approximately as long as broad and approximately 0.8 times as broad as head, widest across anterior angles; anterior and posterior angles marked, distinctly angled; near posterior margin with short diagonal elevation on either side of midline; punctation longitudinally or diagonally confluent; impunctate midline relatively narrow.

Elytra ( Fig. 10 ) 0.90-0.95 times as long as elytra, broad, and with pronounced humeral angles; disc with very coarse, defined, and rather dense macropunctation, and with dense micropunctation. Hind wings fully developed.

Abdomen narrower than elytra; punctation extremely fine and extremely dense; posterior margin of tergite VII with palisade fringe.

: sternite VII ( Fig. 11 ) moderately transverse, with dense pubescence, and with truncate posterior margin; sternite VIII ( Fig. 12 ) weakly transverse, posterior excision rather deep and anteriorly very narrow, nearly reaching middle of sternite; aedeagus ( Fig. 13 ) approximately 0.75 mm long; ventral process with apex of conspicuous shape.

Comment and comparative notes: This species was previously confounded with S. strigosus , a name unintentionally made available ( ROUGEMONT 1985) before the intended description was published ( ROUGEMONT 1986a). ROUGEMONT (1985) studied material from Meghalaya, emphasized a few differences between this material and the type material from Thailand, even gave a rough sketch of the ventral process, but nevertheless considered the Meghalaya populations conspecific with the holotype, suspecting that intermediate forms may occur in the regions between Meghalaya and Thailand.

A comparison of the above material from Northeast India with material from Laos and Vietnam, however, revealed that they undoubtedly refer to different species. Stilicoderus separandus is distinguished from S. strigosus not only by external characters (slightly larger size, longer antennae, presence of distinct and dense micropunctation on the elytra), but particularly by the male sexual characters. In S. separandus , the male sternite VIII is weakly transverse and has a deeper and posteriorly broader posterior excision ( S. strigosus : sternite VIII strongly transverse and with less deep and posteriorly narrower posterior excision) and the ventral process is of distinctly and constantly different shape. For comparison, the aedeagus and the male sternite VIII of S. strigosus are illustrated in Figs 14-15.

Distribution and natural history: The known distribution of S. separandus is confined to several localities in Meghalaya and Assam, Northeast India ( Map 3 ). For additional localities see the records of S. strigosus from Meghalaya in ROUGEMONT (1985). The specimens were collected at altitudes of 400-1200 m.

Figures

Map 3: Distributions of Stilicoderus separandus (white and black circles) and S. turacus (black circle) in Northeast India.

Figs 9-15: Stilicoderus separandus (9-13) and S. strigosus from Laos (14-15): (9) habitus; (10) forebody; (11) male sternite VII; (12, 14) male sternite VIII; (13, 15) aedeagus in lateral view. Scale bars: 9-10: 1.0 mm; 11-12, 14: 0.5 mm; 13, 15: 0.2 mm.