Diochus conicollis ( Motschulsky, 1858 )

Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2016, Taxonomy of the genus Diochus Erichson, 1839 (Coleoptera: Staphylinidae, Staphylininae, Diochini) in China with descriptions of four new species, Zootaxa 4127 (1), pp. 1-30 : 22-25

6. Diochus conicollis ( Motschulsky, 1858)

( Fig. 3 C; Fig. 9 A–O; Fig. 9-1 A–L)

Motschulsky, 1858: 658 ( Rhegmatocerus ; Type locality: Indes orientales); Bernhauer, 1902: 32 ( Diochus ; Ceylon); Bernhauer and Schubert, 1914: 319 (catalog); Bernhauer, 1922: 231 ( Formosa); Cameron, 1932: 46 ( Ceylon; India); Shibata, 1973: 130 ( Taiwan); Coiffait, 1977: 206 ( Bhutan); Coiffait, 1981: 329 (Andaman Islands); Coiffait, 1982: 27 ( Nepal); Herman, 2001: 2445 (catalog); Smetana, 2004: 624 ( Hongkong, Taiwan; Nepal, India, Bhutan); Löbl & Löbl, 2015: 1007 (Palaearctic catalog; Hongkong, Taiwan; Nepal, India, Bhutan).

Syn.: Diochus major Kraatz, 1859: 113 (Type locality: India orientalis; Ceylan); Bernhauer, 1902: 32 (synonym of D. conicollis ); Bernhauer and Schubert, 1914: 319 (synonym of D.conicollis ); Cameron, 1932: 46 (synonym of D. conicollis ); Smetana, 2004: 624 (synonym of D. conicollis ); Löbl & Löbl, 2015: 1007 (Palaearctic catalog; synonym of D. antennatus ).

Type material examined: Lectotype [designated here]: male, “♂”/ “Ind. or”/ “ Diochus conicollis ”, “‘( Motschulsky, 1858)’”, “ LECTOTYPE ”, “Det. Zhou Yulingzi 2016”; Paralectotypes: female,“ Rhegmatocerus ”, “ conicollis ”, “Mots”, “Ind. or. Birma ”/ “ Diochus conicollis ”, “‘( Motschulsky, 1858)’”, “Det. Zhou Yulingzi 2016”; female, “♀”/ “Ind. or”/ “ Diochus conicollis ”, “‘( Motschulsky, 1858)’”, “Det. Zhou Yulingzi 2016”. (ZMM).

Description. Measurement (n=3). BL= (4.9–5.1) mm, FL=(2.0–2.2) mm, HL= (0.5–0.6) mm, HW= (0.4–0.5) mm, PL= (0.7–0.8) mm, PW= (0.6–0.7) mm, EL= (0.6–0.7) mm, EW= (0.7–0.8) mm.

Body nearly fusiform shaped, large sized ( Fig. 3 C). Body dark brown, except elytra darker and abdominal intersegmental membrane yellowish brown ( Fig. 9 O). Legs brown, tarsi distinctly lighter. Antennae brown, apex of each antennomere lighter. Maxillary and labial palpi brown.

Head ( Fig. 9 A, D). Oblong in shape (HL to HW ratio 1.3), tempora (behind eyes) straight and paralleled, posterior angles rounded. Dorsal integument shiny, extensively bearing micropunctures and microstriae, also with 5–7 irregular, scattered punctures around each eye, and numerous smaller punctures on deflexed portion of tempus and near the posterior margin. Each side of cranium with characteristic punctures: one frontal puncture on frontal region, two anterolateral punctures near antennal insertion, three ocular punctures near dorsal margin of eye, temporal puncture at the basal 1/5, also with occipital puncture at the basal 1/4; in addition, disc surface bearing two additional paired punctures with front pair closer. Frontal furrows and anteocular furrows absent, a longitudinal linear elevation present between eyes. Eye medium sized, equal to half the length of tempora (eye: tempora = 0.15: 0.30 mm), distinctly protruding laterad. Epistoma not flattened, abruptly oblique, anterior margin emarginate medially. Distance between antennal insertions 0.15 mm being distinctly longer than distance from antenna to eye (0.09 mm). Ventral surface ( Fig. 9 D) with scattered punctures, interspaces between them ca. 4 punctures’ diameter. Gular sutures deep, confluent at near base.

Antennae ( Fig. 9 G). Total length 1.5 mm. Scape rod-shaped, slightly thickened apically, 0.20 mm, shorter than two subsequent antennomeres combined; antennomere II elongate, 0.10 mm; III 0.15 mm, distinctly longer than II; IV 0.11 mm, IV to X gradually shortened, IV slightly longer than X; XI 0.12 mm, distinctly longer than X.

Mouthparts ( Fig. 9 H–J, P). Labrum transverse ( Fig. 9 H), lateral margin rounded. Mandibles falciform, left one with three small teeth on inner edge, right one with two small tooth ( Fig. 9 I–J).

Neck ( Fig. 9 K–L). Surface shiny and nearly trapezoidal shaped, only bearing shallow microsculpture, with a bisinuate basal furrow near posterior margin ( Fig. 9 K), width of 0.19 mm, obviously wider than 1/3 width of head. Ventral surface with deep gular sutures to form obvious triangular region, which missing transverse median furrow ( Fig. 9 L).

Prothorax ( Fig. 9 B, E). Pronotum elliptical (PL to PW ratio 1.2), distinctly longer and wider than head. Anterior region near anterior angles deflexed and narrowed, lateral margins widened posteriad to basal 1/3 (with the widest at middle), then convergent backwards, anterior and posterior angles broadly rounded. Dorsal surface glossy extensively with micropunctures, but without any microsculpture. Each side of the midline with symmetrical five large lateral punctures, with additional 13–15 punctures near each margins (including anterior, lateral and posterior margins). Prosternum bearing observable transverse ridge between basisternum and furcasternum, which angularly backwards ( Fig. 9 E).

Pterothorax ( Fig. 9 E–F, N). Mesoscutellum triangular and small ( Fig. 9 N). Surface shiny, bearing obvious microstriae, but without any punctures. The transverse ridge on mesoventrites substraight ( Fig. 9 F); the longitudinal ridge distinct; the paired oblique furrows short but deep; the carina (limiting mesocoxal cavity) slightly arcuate. The discrimen region on metaventrite normally elevated.

Elytra ( Fig. 9 C). Transverse and short (EL to EW ratio 0.85), distinctly shorter than pronotum, but wider. Humeri well developed, lateral margins divergent posteriorly, hind margin not rounded, but obliquely truncate. Dorsal integument shiny, flattened, without microsculpture; each elytron with a row of 5 punctures along suture, a row of 5 punctures in median, also with 4–5 rows of punctures on deflexed portion.

Legs ( Fig. 9 M). First four segments of protarsi stout, wider than those of meso- and metatarsi slender. Last segment of protarsi longer than II–IV together; that of mesotarsi meta- longer than II and III together.

Abdomen ( Fig. 9 O). Broadest at segment V. Tergites III–VII covered with dense and obvious transverse microstriae; each tergite with dense yellow pubescence, with a row of darker and coarser setae at posterior margin of III–VI. Tergites III–VII with a basal impression near anterior margin, respectively, each one only possessing one basal transverse carina; surface shiny, bearing polygonal reticulum, but without any punctures. The intersegmental membrane bearing transparent yellow fenestra. All abdominal sternites shiny, with microstriae and punctures as those on tergites.

Male ( Fig. 9-1 A–H). Posterior margin of tergite VIII arcuate ( Fig. 9-1 A), that of sternite VIII slightly emarginate medially ( Fig. 9-1 B), also bearing coarser setae. Tergite IX symmetrical, connected mediobasally ( Fig. 9-1 C), sharpened apically. Sternite IX symmetrical, widest near the middle, with paired longitudinal furrow near each lateral margin, and basal margin wide and subtruncate ( Fig. 9-1 D). Tergite X symmetrical, small and triangular ( Fig. 9-1 C). Aedeagus asymmetrical, fully membranous ventrally and normally sclerotized dorsally, large in size ( Fig. 9 E–G), ca. 0.77 mm long. Parameres symmetrical and slightly curved, thin and slightly 1/3 times the length of basal bulb. Internal sac possessing inner sclerites composed of two parts: two paired sclerites at top (one soft and light color; the other X-shaped and brown color), some black sclerites in centre. Sperm pump coiled, thinned toward apex ( Fig. 9-1 H).

Female ( Fig. 9- 1 I–L). Tergite IX bearing numerous setae, elongate and bluntly pointed apically ( Fig. 9-1 L). Sternite IX symmetrical, each integrated, and with an observable concaved margin in middle ( Fig. 9- 1 I–J). Tergite X nearly triangular, basal margin curved ( Fig. 9-1 L). Sternite X missing. Outer capsule of spermatheca apically swollen, and with more rounded apex margin; tube long, with an apical dilated lobe ( Fig. 9-1 K).

Distribution. China ( Hongkong, Taiwan); Sri Lanka, India, Bhutan, Andaman Islands.

Remarks. This species is distinguished from its congeners by the combination of the following characters: 1) left mandible with three small teeth on inner edge, right with two small tooth ( Fig. 9 I–J); 2) dark coarser setae on the posterior margin of abdominal sternite VIII; 3) pear-like aedeagus with apical paired sclerites; 4) outer capsule of spermatheca swollen.

Figures

FIGURE 3. Habitus of seven species in dorsal view: A. Diochus japonicus Cameron, 1930; B. D. bicornutus sp. nov.; C. D. conicollis (Motschulsky, 1858); D. D. ampullaceus sp. nov.; E. D. bisegmentatus sp. nov.; F. D. membranaceus sp. nov.; G. D. pulchellus Cameron, 1918. Scale bars 0.50 mm.

FIGURE 9. Diochus conicollis (Motschulsky, 1858): A. head, dorsal view; B. pronotum, dorsal view; C. elytra, dorsal view; D. head, ventral view; E. pronotum, ventral view; F. elytra, ventral view; G. antennae; H. labrum; I. left mandible; J. right mandible; K. neck, dorsal view; L. neck, ventral view; M. proleg; N. mesoscutellum; O. basal visiable four segments of abdomen, dorsal view. Scale bars 0.30 mm.