Pelthydrus subgrossus, Bian, Dongju, Schönmann, Heinrich & Ji, Lanzhu, 2009

Bian, Dongju, Schönmann, Heinrich & Ji, Lanzhu, 2009, Five new species of Pelthydrus Orchymont, 1919 from China and adjacent countries (Coleoptera: Hydrophilidae), Zootaxa 2118, pp. 53-64 : 60-61

Pelthydrus subgrossus sp. nov.

( Fig. 3 )

Type material. Holotype (IAECAS) male: “ CHINA: Hubei Province. 24. 10. 2004 / Zhongjian He Nat. Res./ 105 km S Enshi, Xianfeng/ 650 m, leg. Schönmann/ & Wang ( CWBS 551)”. Paratypes: 4 exs. ( NMW), the same data as holotype.

Diagnosis. This species is similar to Pelthydrus grossus sp. nov., but can be distinguished from it by its smaller size, and thicker median lobe of aedeagus.

Description. Body length 3.1 mm – 3.3 mm; width 2.0 mm– 2.2 mm. broadly oval and distinctly convex, somewhat acute in posterior portion; complete surface shining, dark black; lateral margins of head, pronotum, labial and maxillary palpi, tibae and tarsi reddish brown, antennae yellowish brown.

Head trapezoidal, about 1.8 times wider than long; gradually widened towards posterior part; lateral sides smooth; median-sized punctures densely distributed; innersides of eyes distinctly wrinkled; clypeal suture distinct; anterior margin of clypeus truncated, anterior corners roundly angulate.

Pronotum trapezoidal, about 2.3 times wider than long, punctuation a little larger than that on head; lateral margins narrowly ridged, anterior margin somewhat arched at middle; anterior corners angulated, posterior corners broadly rounded.

Elytra about 1.3 times longer than wide; broadest part at one fourth from base, from there distinctly narrowed posteriorly; punctuation much smaller and sparser than head and pronotum.

Ventral side mostly reddish brown to dark brown; mentum dark brown, somewhat rugulose; prosternum yellowish with a medio-longitudinal carina; mesosternum elevated posteriorly producing a triangular plate, which has a round apical part and a longitudinal carina at middle; metasternum has a “M” shaped projection at base, and elevated towards posterior part, with an elongate oval and glabrous area posteriorly.

Aedeagus ( Fig. 3 ). 0.67 mm long, nearly paralleled, phallobase approximately as long as the median lobe; median lobe very thick, with paralleled sides, ending with a round point; parameres a little longer than median lobe with sharp apices at innersides.

Distribution. China (Hubei Province).

Etymology. This species is named in reference to its similarity with Pelthydrus grossus sp. nov.

Figures

FIGURES 1 – 6: Aedeagus in dorsal view. 1. Pelthydrus grossus sp. nov. (holotype); 2. Pelthydrus grossus sp. nov. (paratype from Laos); 3. Pelthydrus subgrossus sp. nov.; 4. Pelthydrus longifolius sp. nov.; 5. Pelthydrus rosa sp. nov.; 6. Pelthydrus yulinensis sp. nov.