Hexachaetus brunki, Tian, Mingyi & Deuve, Thierry, 2016

Tian, Mingyi & Deuve, Thierry, 2016, Re-definition and review of the Oriental genus Hexachaetus Chaudoir, 1871 (Coleoptera: Carabidae: Orthogoniini), Zootaxa 4169 (3), pp. 540-554 : 548-549

Hexachaetus brunki , n. sp.

( Figures 7 , 16–17 )

Material. Holotype male, “ Boneo-North , Sabah Trus Madi, 1500 m, May 2011, leg. K. P. Yeb ( Malaysia), in CIB.

Diagnosis. Medium-sized for lateralis species group, body moderately elongate-ovate, smooth, polish, impunctate and yellowish; head, longitudinal median portion of pronotum, and central marking of elytra black; elytral marking anchoreaform, wider; ligula 6-setose, clypeus bisetose, middle tibia slightly dilated in male; pronotum strongly convex, lateral expanded margin indistinctly reflexed, hind angle round off, elytra strongly and obliquely truncate at apex, inner apical angle acute and sharp, striae rather deep, intervals convex.

Length: 15.5 mm; width: 6.0 mm. Habitus as in Fig. 7 .

Description. Yellow, but head (except labrum and median areas of clypeus and frons), median portion of pronotum and elytra median, and tibiae dark brown; palps, antennae and tarsi brown; elytra marking anchoreaform, occupied intervals 1 to 4 in the widest points, ending at about apical 2/11 portion of elytra, margins without marking throughout; head and pronotum smooth, glabrous, elytra with tiny and irregular punctures on intervals; microsculptural engraved meshes vanished on head, striate on pronotum, isodiametric on elytra.

Head stout, as long as wide, clypeus somewhat uneven at base, bisetose; eyes large and very prominent, frontal impressions well-marked, foveate, short, finishing the level of fore supraorbital punctures; frons and vertex moderately convex; mandibles stout, apex moderately hooked; mentum and submentum each with a pair of setae, palpiger unsetose, ligula slightly enlarged, 6-setose at apex, central one pair of setae longest, middle pair longer than outer pair; palps subcylindrical, short and stout, maxillary palpomeres 3 and 4 subequal; labial palpomere 2 much longer (1.5 times) than 3, bisetose on inner margin; labrum nearly quadrate, front margin straight, 6-setose, surface smooth. Antennae moderately long, extending over base of elytra, pubescent from antennomere 4, concolorous; antennomere 1–3 glabrous, antennomere 1 with a long seta at subapex, and several shorter setae at apexes of 1–3; antennomere 1 about twice as long as antennomere 2, and slightly longer than 3;

Pronotum transverse, PW/PL=1.70, widest at about middle; disc markedly convex, smooth and glabrous; both front and basal margin bordered, transversal impressions well-marked, median line distinct; lateral expanded margins narrow at front, then gradually widened towards base, quite flat throughout; front margin straight at middle, basal margin faintly bisinuate, median portion hardly produced backwards; hind and front angles round off; basal foveae shallow and faint.

Elytra elongate-ovate, convex; EL/EW=1.70; near parallel-sided, widest at middle; base well bordered, apex deeply and obliquely truncate, outer angles pointed, inner angles very sharp; striae rather deep, intervals convex, odd and even intervals subequal at middle; interval 3 with basal and subapical setiferous pores, basal one wellmarked, closed to stria 3, subapical one small, at about middle of the interval.

Fore tibia slightly dilated at apex, apex slightly arcuate, outer margin sub-serrate; middle tibia not evidently dilated at middle in male; hind legs slender, apex only slightly enlarged, apical spurs long and sharp, tarsomere 1.5 times as long as tarsomere 2; tarsomere 3 as long as 4 which is deeply bilobed at apex; all tarsal claws strongly pectinate.

Prosternal process unbordered at apex; abdominal ventrite VII of male small but deeply emarginate at middle.

Male genitalia ( Figs. 16–17 ): The median lobe of aedeagus short and stout, slightly sinuate ventrally, expanded medially, apex sharp in lateral view, dorsal open quite large; in dorsal view, the apical lamella is rather long though distinctly shorter than wide, broadly rounded at apex.

Female: Unknown.

Remarks. This species is allied to O. kirschenhoferi n. sp., but differs from the latter species by: large-sized body, more transverse pronotum in front, elytra marking not extended to margin areas, and aedeagus sharp at apex (versus blunt in O. kirschenhoferi ), with a longer apical lamella.

Etymology. In honour of Dr. Ingo Brunk (Dresden, Germany).

Distribution. Malaysia ( Fig. 20 e).

Figures

FIGURE 20. Distribution of Hexachaetus species (square: angulatus species group; round: lateralis species group; star: laevissimus species group; heart: vietnamensis species group; triangle: mulan species group; a. H. lateralis lateralis; b. H. lateralis maindroni; c. H. maculatus; d. H. kirschenhoferi n. sp.; e. H. brunki n. sp.; f. H. laevissimus; g. H. vietnamensis n. sp.; h. H. prodigus; i. H. mulan n. sp.)

FIGURES 5 – 8. Habitus of Hexachaetus species (5. H. maculatus Tian & Deuve, male, the holotype; 6. H. kirschenhoferi n. sp., male, holotype (photo: E. Kirschhofer); 7. H. brunki n. sp., male holotype; 8. H. laevissimus Chaudoir, 1878, female. Scale bar: 5.0 mm)

FIGURES 12 – 19. Male genitalia of Hexachaetus species, right lateral view and dorsal view for apical lamella (12 – 13. H. maculatus Tian & Deuve; 14 – 15. H. kirschenhoferi n. sp.; 16 – 17. H. brunki n. sp.; 18 – 19. H. vietnamensis n. sp.)