Thinobius schillhammeri, Makranczy & H-, 2014

Makranczy, György, 2014, The Far Eastern species of Thinobius Kiesenwetter, 1844 (Coleoptera: Staphylinidae, Oxytelinae) lacking female modified genital appendage, Revue suisse de Zoologie 121 (3), pp. 319-347 : 332-336

Thinobius schillhammeri sp. nov. Figs 5, 15-16, 33-35, 50, 58-60, 79

TYPE MATERIAL: HNHM, holotype (3); “S-KOREA, Gangwon-do, Seorak-san, Osaek- Oncheon, N branch of Osaekcheon stream, stony bank, 370 m, rough sand partly under stones, flotation (4A), 38°04'48"N, 128°26'58"E; 09.IX.2010; [leg.] Makranczy & al.”. PARATYPES (5): HNHM 1♀, 1, NIBR 1 , NHMW 1 , MHNG 1 ; same data as holotype .

DESCRIPTION: Habitus as in Fig. 5. Measurements (n=6): HW = 0.28 (0.26- 0.29); TW = 0.28 (0.265-0.295); PW = 0.32 (0.305-0.325); SW = 0.33 (0.32-0.33); AW = 0.38 (0.36-0.40); HL = 0.22 (0.21-0.23); EL = 0.08 (0.08-0.085); TL = 0.08 (0.07- 0.08); PL = 0.25 (0.24-0.255); SL = 0.39 (0.35-0.415); SC = 0.34 (0.33-0.355); FB = 0.86 (0.82-0.90); BL = 1.48 (1.35-1.55) mm. BODY slightly bicoloured. Head, pronotum and abdomen blackish dark brown with occasional reddish tint; elytra medium brown, but narrowly darker around scutellum. Mouthparts, antennae and legs medium to dark brown, tibiae and tarsi lighter, yellowish light brown. Forebody with microsculpture intermixed with fine and dense punctation, making it moderately lustrous; abdomen with microsculpture composed of transversal micro-ridges and microsetation (Figs. 34-35) resulting in a dull, iridescent appearance. Head and pronotum with coriaceous microsculpture and inconspicuous punctation. Elytra dominated by more imbricate microsculpture and only very obscured, dense and tiny punctures. Abdominal tergites with only traces of scattered punctation, rather shallow and indistinct; surface dominated by transversal substrigulate microsculpture. Tergite VIII rarely exposed but with smoother surface. Pubescence on head and pronotum fine, medium FIGS 32-37

short and depressed; elytra with extremely fine and short, more dense setae. Abdomen with short and very sparse setae, plus a row of conspicuously long setae on apical edges of tergites. Abdominal sides and apex with a few darker, not too long but stronger bristles. Strong dark bristle on outer side of supraantennal tubercle at anterior border of eye and on posterior edge of vertex adjacent to temples, similar ones right behind anterior pronotal corner and on side at 3/5 length. Direction of setation on head and pronotum anterior in midlines plus posterior edge of pronotum, on discs anteromedial; anteriad neck rather mixed. Elytra and abdomen with posteriorly directed setae. Antennae, legs and mouthparts with very short, not conspicuous setation, except for the stiff, darker bristle near middle of each tibia and ones near apices of femora. Sides of elytra with three stiffer (but inconspicuous) setae equally distributed on side, closer to each other (anterior one more behind shoulder, posterior more before outer corner) than usual.

Head (Fig. 15) 1.30x wider than long, temples (Fig. 16) usually straight or slightly narrowing, with a gently curve anteriorly, narrowly rounded posteriorly. Marked groove at inner edge of eye, continuing at side of a ridge at outer border of supraantennal prominence, latter with deep groove marking its inner border with clypeus; clypeus as strongly microsculptured as rest of head. Anterior border of neck marked with strong, curved groove. Frontoclypeal suture appearing as fine, shinier groove connecting supraantennal tubercles. ANTENNAE moderately elongate (Fig. 50), antennomeres 4-8 all slightly elongate, 9 and 10 significantly larger than preceding ones.

Pronotum slightly transverse, 1.30x wider than long, a little wider than head. Weakly arched sides plus anterior and posterior margins with narrowly rounded anterior and posterior corners giving pronotum a distinctly rectangular appearance. Pronotal disc inconspicuously impressed around middle of disc as well as slightly behind middle of sides; areas of posterior corners slightly elevated. Pronotal marginal bead visible on posterior and side margins. Scutellum large, setose and dull. ELYTRA (Fig. 33) moderately long, one elytron up to twice as long as broad, quite flat and parallel-sided (very little dilation posteriorly). Shoulders moderately developed. Along suture without marginal bead, sutural corners moderately broadly rounded. LEGS of medium length, tarsal lobes thin but relatively thin but long (sometimes reaching apex of last tarsomere), tibiae rather fusiform, appear much wider in middle than at ends.

Abdomen very weakly fusiform, sides more or less straight and parallel; widest in the middle, very slightly less wide than elytra at broadest point. Posterior margin of tergite VII with thin palisade fringe, posterior corners conspicuously broadly rounded.

PRIMARY AND SECONDARY SEXUAL FEATURES: Sexes not appearing different in regular dorsal view. Posterior corners of tergite VIII (similar in both sexes) gently protruding, posterior edge otherwise straight. Male sternite VIII as in Fig. 58, tergite IX as in Fig. 59, sternite IX as in Fig. 60. Aedeagus as in Fig. 79.

ETYMOLOGY: Named after Dr. Harald Schillhammer (Wien, Austria), who provides continuous help with colour habitus photography in a quality rarely seen for such tiny insects.

REMARKS: As for body size no sexual dimorphism was experienced with this species. A member of the Thinobius linearis group, it is the closest known relative of FIGS 38-44

(38-39) Thinobiusootsukai Naomi; elytron (38), antenna (39). (40-42) T. yabakeinis Naomi ; elytron (40), antenna (41), sideofhead (42). (43) T. injae sp. n.; abdomen, dorsal. (44) T. zerchei Gildenkov ; abdomen, dorsal. Scale bar = 0.06 mm for 42, 0.1 mm for 38, 0.13 mm for 40, 43, 0.16 mm for 39, 41, 0.2 mm for 44.

T. heterogaster Fauvel, 1889 . This record broadens the known distribution range of the group. The new species is slightly larger than T. heterogaster , with stronger antennae. The most important diagnostic difference is the pronotal shape: T. heterogaster has conspicuous obtuse-angled posterior pronotal corners and almost straight pronotal sides and only a slight protuberance in near the posterior pronotal corners, while T. schillhammeri has a barely noticeably angled posterior pronotal corner, more curved sides and stonger protuberances near the posterior corners.

DISTRIBUTION: The species is known only from the type locality (Fig. 7).

BIONOMICS: The type material was collected in sandy-gravelly spots between huge rocks or under stones at a fast-running mountain stream.