Coelostoma (Lachnocoelostoma) huangi, Jia, Fenglong, Aston, Paul & Fikáček, Martin, 2014

Jia, Fenglong, Aston, Paul & Fikáček, Martin, 2014, Review of the Chinese species of the genus Coelostoma Brullé, 1835 (Coleoptera: Hydrophilidae: Sphaeridiinae), Zootaxa 3887 (3), pp. 354-376 : 368-369

Coelostoma (Lachnocoelostoma) huangi sp. nov.

( Fig. 27 )

Type material. HOLOTYPE: male, GUANGXI, Jingxi, Bangliang Nature Reserve, 6.viii.2010, Jianhua Huang leg. [transcribed from Chinese] ( SYSU). PARATYPES: 3 males, 5 females, same data as holotype ( SYSU). JIANGXI: 1 male, Jiulianshan Mount, Daqiutian (trapped in light), 30.viii.2007, Hong Pang leg. [transcribed from Chinese] ( SYSU).

Diagnosis. Body length 5.1–5.5 mm. Prosternum moderately carinate throughout medial portion and forming a finger-shape anteromedian process. Head, pronotum and elytra with similar punctation; elytra with lateral portion more or less strongly punctate, without traces of series of punctures laterally. Mesofemora densely pubescent, except at extreme apex. First abdominal ventrite distinctly carinate, fifth ventrite emarginate and with a row of stout setae apically. Aedeagus ( Fig. 27 ): 0.80 mm long. Median lobe rather broader than parameres, not emarginate apically, gonopore subapical; parameres longer than median lobe, outer face of parameres abruptly curved in apical fourth, apical margin truncate, inner face obliquely truncate apically.

Description. Form and Color. Body length 5.1–5.5 mm, width 3.1–3.2 mm. Body oval, strongly convex. Dorsum black. Labrum, maxillary palpi, labial palpi yellowish to reddish brown, antennae yellowish to reddish brown with dark club. Ventral surface black with reddish pubescence. Femora and tibiae dark reddish brown, tarsi pale reddish.

Head. Surface with dense and moderately strong punctures. Intervals between punctures smooth, but with transverse microsculpture extremely posteriorly (this part sometimes covered by pronotum). Clypeus truncate anteriorly. Eyes moderately sized, separated by ca. 5× the width of one eye, not emarginate anteriorly. Mentum with transverse microsculpture and strong punctures, strongly emarginate anteriorly and depressed anterior half. Antennae with 9 antennomeres, antennal club loosely segmented. Maxillary palpomere 2 strongly swollen, palpomere 4 almost symmetrical, rather longer than palpomere 3. Gula very narrow, glabrous.

Thorax. Punctures of pronotum similar to that on head; anterior margin strongly bisinuate; posterior margin slightly bisinuate; lateral marginal bead reaching posterior corner, not continuing to posterior margin; posterior corner almost rectangular. Prosternum moderately carinate throughout medial portion and forming a strong fingershape anteromedian process. Mesoventrite with raised, arrowhead-shaped process, surface pubescent. Metaventrite with strongly raised median portion broadly projecting anteriorly between mesocoxae and widely meets mesoventral process; lateral portions of metaventrite densely pubescent, middle portion more shining, only sparsely pubescent. Metepisterna ca. 5× as long as wide, parallel-sided. Scutellar shield slightly longer than wide, with punctuation as on pronotum. Elytra with similar punctation as on pronotum, lateral and posterior punctures slightly coarser than those on disc, without traces of series; sutural stria reaching basal half of elytra. Femora with deep tibial groove posteriorly. Mesofemora densely pubescent, except at extreme apex. Metafemora sparsely punctate, with dense microsculpture. Tarsi with long dorsal setae and gold ventral setae; metatarsi with last tarsomere longer than third and fourth combined. Claws moderately curved, with a pair of long setae beneath.

Abdomen. Abdominal ventrites densely pubescent. First abdominal ventrite with a sharp carina reaching over posterior third; last ventrite somewhat truncate, with a row of stout setae apically.

Aedeagus ( Fig. 27 ). 0.80 mm long. Median lobe broader than parameres, not emarginate apically, gonopore subapical; parameres longer than median lobe, outer face of parameres abruptly curved in apical fourth, apical margin truncate, inner face obliquely truncate apically.

Etymology. The species is dedicated to Dr. Guohua Huang, the donor of the type specimens.

Biology. All type specimens were collected in light trap.

Remarks. This species is very similar to C. martensi Hebauer, 2002 ( Fig. 28 ) from Nepal, and C. coomani diversum Orchymont, 1932 from Sumatra. It can be distinguished from C. martensi by larger size (4.5× 2.9 mm in C. martensi ), elytra without any trace of series of punctures, median lobe of aedeagus not so broad and dilated medially and parameres with inner face obliquely truncate apically; from C. coomani diversum it differs by larger size (4.4× 2.8 mm in C. coomani diversum ), outer face of parameres abruptly curved in apical fourth (gradually curved in C. coomani diversum ), apical margin broadly truncate (narrow and subtruncate in the latter species), inner face shortly obliquely truncate apically (long and obliquely truncate apically in the latter species).

Distribution. China (Jiangxi, Guangxi).

Figures

FIGURES 24 – 31. Aedeagus of Chinese Coelostoma and related species. 24: C. coomani, 25: C. gentilii sp. nov., 26: C. phallicum, 27: C. huangi sp. nov., 28: C. martensi (paratype from Nepal), 29: C. wui, 30: C. vagum, 31: C. horni from southern Yunnan: Xishuangbanna).