Diochus ampullaceus, 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 : 10-13

2. Diochus ampullaceus sp. nov.

( Fig. 3 D; Fig. 5 A–P; Fig. 5-1 A–J)

Type material. Holotype: male, CHINA: Guangxi: Napo co., Defushuiyuanlin Nature Reserve (E 105.7965°, N 23.3148°), 1400 m, 0 4. IV.1998, Zhou Haisheng collected (IZ-CAS). Paratypes: Guangxi: Napo co., Defushuiyuanlin Nature Reserve (E 105.7965°, N 23.3148°), 3 males, 4 females, 1400 m, 0 4. IV.1998, Zhou Haisheng collected (IZ-CAS).

Description. Measurement (n=5). BL= (4.2–4.3) mm, FL= (2.1–2.2) 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= (0.8–0.9) mm.

Body nearly fusiform shaped, medium sized ( Fig. 3 D). Body dark brown, abdominal intersegmental membrane yellowish brown. Legs entirely brown, except tarsi lighter. Antennae light brown. Maxillary and labial palpi yellowish brown.

Head ( Fig. 5 A, D). Rounded triangular in shape (HL to HW ratio 1.23), tempora (behind eyes) distinctly widened backwards, posterior angles rounded. Dorsal integument shiny, extensively bearing 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 at the basal 1/4, but temporal puncture unidentified; besides, disc surface bearing two additional paired punctures. Frontal furrows and anteocular furrows absent, a small round elevation present between eyes. Eye medium sized, distinctly protruding laterad, longitudinal diameter slightly shorter than half the length of tempora (eye: tempora = 0.16: 0.34 mm). Epistoma not flattened, abruptly oblique, anterior margin emarginate medially. Distance between antennal insertions 0.17 mm being distinctly longer than distance from antenna to eye (0.09 mm). Ventral surface ( Fig. 5 D) with scattered punctures, interspaces between them over 4 punctures’ diameter. Gular sutures deep, gradually convergent, but not confluent, then divergent to neck region.

Antennae ( Fig. 5 G). Total length 1.2 mm. Scape rod-shaped, slightly thickened apically, 0.17 mm, shorter than two subsequent antennomeres combined; antennomere II elongate, 0.12 mm; III 0.13 mm, slightly longer than II; IV 0.09 mm, IV–X becoming shortened in length; XI 0.14 mm, distinctly longer than X.

Mouthparts ( Fig. 5 H–J). Labrum not transverse, nearly pentagon; lateral margin straight, not in waved shape; anterior margin distinctly shorter than lateral margins ( Fig. 5 H). Mandibles falciform, left one with one sharp tooth on inner edge, right one without tooth ( Fig. 5 I–J).

Neck ( Fig. 5 K–L). Cylindrical, shiny, first half of dorsal surface depressed, with a distinct groove ( Fig. 5 K); only bearing shallow microsculpture, width of 0.17 mm, slightly wider than 1/3 width of head. Ventral surface with gular sutures to form obvious triangular region, with deep transverse median furrow ( Fig. 4 L).

Prothorax ( Fig. 5 B, E). Pronotum elliptical (PL to PW ratio 1.09), wider and longer than head. Anterior region near anterior angles deflexed, lateral margins paralleled, not widened from anterior angles to the middle, also not 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 an observable transverse ridge between basisternum and furcasternum, angularly backwards ( Fig. 5 E).

Pterothorax ( Fig. 5 F, N). Mesoscutellum slightly sharp triangular and small ( Fig. 5 N), surface shiny, bearing some light microstriae, but without any punctures. The transverse ridge on mesoventrites substraight ( Fig. 5 F); the longitudinal ridge distinct; the paired oblique furrows not distinct; the carina (limiting mesocoxal cavity) possessing wave-shaped median part. The discrimen region on metaventrite distinctly elevated.

Elytra ( Fig. 5 C). Transverse and short (EL to EW ratio 0.81), shorter and wider than pronotum. 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. 5 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 meso- as long as II and III together; that of meta- longer than II and III together.

Abdomen ( Fig. 5 O). Broadest at segment V. Tergites III–VII covered with dense and obvious 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, without any punctures or microsculpture. Tergite VII possessing a transparent palisade fringe on posterior margin. All abdominal sternites shiny, with microstriae and punctures as those on tergites.

Male ( Fig. 5-1 A–G). Posterior margin of tergite VIII arcuate backwards ( Fig. 5-1 A), that of sternite VIII distinctly bisinuate ( Fig. 5-1 B). Tergite IX symmetrical, connected mediobasally, sharpened apically. Sternite IX symmetrical, widest near the apical 1/3, basal margin deeply emarginate, apical margin nearly subtruncate ( Fig. 5- 1 D). Tergite X symmetrical, in reverse trapezoidal shape ( Fig. 5-1 C). Aedeagus large sized and bottle-shaped ( Fig. 5 E, F), ca. 0.8 mm long, ventral surface normally sclerotized, with part membrane; dorsal surface fully membranous. Parameres symmetrical and soft, extraordinarily thin and long, rolled from ventral to dorsal side ( Fig. 5-1 E, F). Internal sac membranous, without sclerotized structures. Sperm pump folded basally, spiral toward apex ( Fig. 5-1 G).

Female ( Fig. 5-1 H–J). Tergite IX bearing numerous setae, elongate and sharply pointed apically. Sternite IX symmetrical, each integrated, and with a deep concaved margin in the middle ( Fig. 5-1 H). Tergite X broad, basal margin curved ( Fig. 5- 1 I). Sternite X missing. Tube of spermatheca short, with an apical circle ( Fig. 5-1 J).

Distribution. Guangxi.

Etymology. The specific epithet is derived from the Latin word “ ampullaceus ” (a flask swelled in middle) and refers to the bottle-shaped aedeagus.

Remarks. Although this new species is similar in the round elevation between the eyes to D. pulchellus Cameron , it can be easily recognized by the dilated protarsi. This new species is distinguished from its congeners by the combination of the following characters: 1) sparsely distributed punctures on head; 2) different number of mandible teeth; 3) neck with both a dorsal and ventral groove; 4) transverse elytra; 5) aedeagus large sized and bottle-shaped ( Fig. 5 E, F); parameres symmetrical and soft, extraordinarily thin and long, curving from ventral to dorsal side ( Fig. 5-1 E, F).

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 4. Diochus bicornutus sp. nov.: 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 & cervical sclerites, ventral view; M. proleg; N. mesoscutellum; O. basal visiable four segments of abdomen, dorsal view; P. labial & maxillary palpi, ventral view. Scale bars 0.30 mm.

FIGURE 5. Diochus ampullaceus sp. nov.: 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 & cervical sclerites 1, ventral view; M. proleg; N. mesoscutellum; O. basal visiable three segments of abdomen, dorsal view; P. maxillary palpi, ventral view; Q. antesternal plate. Scale bars 0.10 mm.