Diochus bisegmentatus, Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2016

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 : 13-17

publication ID	https://doi.org/ 10.11646/zootaxa.4127.1.1
publication LSID	lsid:zoobank.org:pub:9E858916-3F3A-4D87-B987-B62CE241CED0
DOI	https://doi.org/10.5281/zenodo.6063249
persistent identifier	https://treatment.plazi.org/id/7C5887A3-FFEC-B24D-FF6A-F8B5377CFCED
treatment provided by	Plazi
scientific name	Diochus bisegmentatus
status	sp. nov.

Treatment

3. Diochus bisegmentatus View in CoL sp. nov.

( Fig. 3 View FIGURE 3 E; Fig. 6 View FIGURE 6 A–O; Fig. 6-1 View FIGURE 6 A–L)

Type material. Holotype: male, CHINA: Hainan: Ledong co., Wuzhishan City (E 109.5169°, N 18.7751°), 785 m, 08.VII.2004, Wu Jie & Chen Yongjie collected (IZ-CAS). Paratypes: Yunnan: Mengla co.: Longmen village, Xiaoniupeng (E 101.3252°, N 21.3095°), one male, 4 females, 1010 m, 06.X.2010, Zhou Yu-Lingzi collected ( IZ- CAS); Menglun Xipian (E 101.2489°, N 21.9353°), one female, 720 m, 16.II.2004, Wu Jie collected (IZ-CAS); Menglun (E 101.2490°, N 21.9375°), one female, 860 m, 11.II.2004, Wu Jie & Bai Daiyuan collected (IZ-CAS); Hainan: Ledong co., Wuzhishan City (E 109.5169°, N 18.7751°), one female, 770 m, 07.VII.2004, Wu Jie & Chen Yongjie collected (IZ-CAS); Lingshuilizu autonomous co., Diaoluoshan (E 109.9160°, N 18.6598°), one female, 920 m, 28.VII.2004, Wu Jie & Chen Yongjie (IZ-CAS).

Description. Measurement (N=5). BL= (3.9–4.0) mm, FL= (2.2–2.3) 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= (0.7–0.8) mm, EW= (0.8–0.9) mm.

Body nearly fusiform shaped, small sized ( Fig. 3 View FIGURE 3 E). Body entirely dark brown; abdominal intersegmental membrane yellowish brown. Antennae dark brown. Leg, maxillary and labial palpi yellowish brown.

Head ( Fig. 6 View FIGURE 6 A, D). Rectangular in shape (HL to HW ratio 1.21), tempora (behind eyes) distinctly widened backwards, posterior angles rounded. Dorsal integument shiny, extensively bearing microsculpture mixed by polygonal reticulum (mainly on frontal region) and microstriae, without punctures around each eye, but bearing scattered 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 lateral punctures near dorsal margin of eye, also with occipital puncture and temporal puncture near posterior margin; besides, disc surface bearing two additional paired punctures. Frontal furrows and anteocular furrows absent, a little round elevation present between eyes. Eye medium sized, distinctly protruding laterad, longitudinal diameter equal to half the length of tempora (eye: tempora = 0.17: 0.34 mm). Epistoma not flattened, abruptly oblique, anterior margin subtruncate. Distance between antennal insertions 0.15 mm being distinctly longer than distance from antenna to eye (0.07 mm). Ventral surface ( Fig. 6 View FIGURE 6 D) with scattered punctures, interspaces between them over 4 punctures’ diameter. Gular sutures deep, confluent at basal 1/4, then extended to neck region.

Antennae ( Fig. 6 View FIGURE 6 G). Total length 1.1 mm. Scape rod-shaped, slightly thickened apically, 0.19 mm, slightly shorter than two subsequent antennomeres combined; antennomeres II and III equal in length of 0.10 mm; IV–VII of rectangular shape, subequal in length of 0.09 mm; VIII of square shape, IX and X transverse and becoming shortened, sometimes VIII–X square in shape and with same length; XI 0.14 mm, distinctly longer than X.

Mouthparts ( Fig. 6 View FIGURE 6 H–J). Labrum transverse, anterior margin slightly emarginate medially; lateral margin arcuate ( Fig. 6 View FIGURE 6 H). Mandibles falciform, left one with three small teeth on inner edge, right one with two sharper teeth ( Fig. 6 View FIGURE 6 I–J).

Neck ( Fig. 6 View FIGURE 6 K–L). Cylindrical, shiny, apical 1/3 of dorsal surface depressed, with a distinct groove; only bearing shallow microsculpture, width of 0.17 mm, slightly wider than 1/3 width of head ( Fig. 6 View FIGURE 6 K). Ventral surface with gular sutures to form obvious triangular region, with deep transverse median furrow ( Fig. 6 View FIGURE 6 L).

Prothorax ( Fig. 6 View FIGURE 6 B). Pronotum rectangular (PL to PW ratio 1.19), distinctly wider and longer than head. Anterior region near anterior angles deflexed, lateral margins arcuate, with widest at basal 1/3. 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 an observable transverse ridge between basisternum and furcasternum, angularly backwards ( Fig. 6 View FIGURE 6 E).

Pterothorax ( Fig. 6 View FIGURE 6 F, N). Mesoscutellum slightly sharp triangular and medium sized ( Fig. 6 View FIGURE 6 N), surface shiny, bearing some light microstriae, but without any punctures. The transverse ridge on mesoventrites wave-shaped ( Fig. 6 View FIGURE 6 F); the longitudinal ridge distinct; the paired oblique furrows long but not deep; the carina (limiting mesocoxal cavity) possessing median horizontal part. The discrimen region on metaventrite distinctly elevated.

Elytra ( Fig. 6 View FIGURE 6 C, F). Rectangular and long (EL to EW ratio 0.84), slightly longer than pronotum, but distinctly 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. 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 meso- as long as II and III together; that of meta- longer than II and III together.

Abdomen ( Fig. 6 View FIGURE 6 O). Broadest at segment V. Tergites III–VII covered with dense and transverse microstriae; each tergite with dense and brown pubescence, posterior margin of III–VI without darker and coarser setae. Tergites III–VII with a basal impression near anterior margin, respectively, each one only possessing one basal transverse carina; surface shiny, with microsculpture composed of polygonal reticulum. Tergite VII possessing a transparent palisade fringe on posterior margin. All abdominal sternites shiny, with microstriae and punctures as those on tergites.

Male ( Fig. 6-1 View FIGURE 6 A–G). Posterior margin of tergite VIII arcuate backwards ( Fig. 6-1 View FIGURE 6 A), that of sternite VIII distinctly bisinuate ( Fig. 6-1 View FIGURE 6 B). Tergite IX symmetrical, connected mediobasally, sharpened apically. Sternite IX symmetrical, widest at middle, basal margin deeply emarginate, apical margin nearly subtruncate ( Fig. 6-1 View FIGURE 6 D). Tergite X symmetrical and triangular ( Fig. 6-1 View FIGURE 6 C). Aedeagus medium sized ( Fig. 6 View FIGURE 6 E, F), ca. 0.4 mm long, dorsal and ventral surface bearing obvious membranous part, apical margin bisinuate, basal margin waved. Parameres symmetrical, extraordinarily thin and long, cross at dorsal side ( Fig. 6-1 View FIGURE 6 E, F). Internal sac with symmetrical and sclerotized structures. Sperm pump short and folded basally, thinned toward apex ( Fig. 6-1 View FIGURE 6 G).

Female ( Fig. 6-1 View FIGURE 6 H–L). Tergite IX bearing numerous setae, stout, with a sharp apical point ( Fig. 6-1 View FIGURE 6 K). Sternite IX symmetrical, each two-segmented ( Fig. 6-1 View FIGURE 6 H). Tergite X nearly triangular, basal margin distinctly curved ( Fig. 6- 1 View FIGURE 6 I). Sternite X slender and pentagonal ( Fig. 6-1 View FIGURE 6 L). Tube of spermatheca long, with an apical circle ( Fig. 6-1 View FIGURE 6 J).

Distribution. Hainan, Yunnan.

Etymology. The specific epithet is derived from the combinations of Latin adverb “ bis ” (twice) and the adjective “ segmentatus ” (composed of strips, bands), and refers to female sternite IX seemed two segmented.

Remarks. This new species is distinguished from its congeners by the following characteristics: 1) polygonal reticulum on frontal region; 2) a little round elevation on head; 3) longer elytra; 4) number of the mandible teeth; 5) transverse ridge on mesoventrite wave-shaped ( Fig. 6 View FIGURE 6 F); 6) dorsal and ventral surface of aedeagus bearing obvious membranous part, apical margin bisinuate, basal margin waved. Although the shape of antennae is similar to that of D. antennatus (Motschulsky) (per. comm. with Jiri Janak), the paired parameres are extremely longer, and the outer margin of aedeagus is quite different: basal margin as waved-like, and apical margin sharply concaved.