Pelthydrus yulinensis, 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 : 63-64

Pelthydrus yulinensis sp. nov.

( Fig. 6 )

Type material. Holotype (IAECAS) male: “ CHINA: Guangxi/ Yülin, Liuwan/ ca. 100 m, leg. L. Ji/ 1993. XI. 18 ”. Paratypes: 3exs. (IAECAS), the same data as holotype; 15 exs. ( NMW), CHINA: SE-Guangxi Distr. Yulin ( CWBS 42); 2 exs. ( NMW), CHINA: SE-Guangxi Distr., Yulin ( CWBS 45); 1 ex. ( NMW), CHINA: SE-Guangxi Distr., Yulin ( CWBS 46); 8 exs. ( NMW), CHINA: SE-Guangxi Distr., Yülin ( CWBS 49).

Diagnosis. The habitus of this species is similar to P. dudgeoni but can be easily distinguished by the different shape of median lobe, the distal half of which is gradually narrowed toward the apical part in P. yulinensis , while almost paralleled firstly, then sharpened in P. dudgeoni . The median lobe is distinctly shorter than the parameres in P. yulinensis , but almost the same in length in P. dudgeoni .

Description. Body length 3.3 mm, width 2.1 mm; broad oval, moderately convex. Head, elytra, femora and tibiae dark brown, pronotum, lateral sides of head and elytra, maxillary palpi and tarsi ferruginous.

Head trapezoidal, subparallel-sized, about 1.7 times as wide as long, distinctly narrower than pronotum, strongly punctuate, denser in posterior portion, innersides of eyes more or less wrinkled, with frontoclypeal suture distinctly impressed. Anterior corners of clypeus acute. Labrum hardly detectable in dorsal view. Antennae yellowish-brown, 8-segmented, 5th segment large and cup-shaped, terminal three segments forming a club. Maxillary palpi distinctly longer than antennae, with approximate ratio of 2nd, 3rd, 4th segments 20: 17: 30 in length.

Pronotum sub-trapezoidal, about 2.8 times as wide as long, lateral and anterior margins narrowly bordered, anterior margin arched at middle. Punctures denser and larger than those on head. Scutellum triangular, sparsely scattered with large punctures.

Elytra: broadest at one fourth from base, then slightly narrowed anteriorly and strongly narrowed towards posterior portion, about 1.1 times as long as wide, lateral margins narrowly bordered and strongly reflexed. Dorsum densely scattered with medium-sized punctures which are denser and smaller than on pronotum, with very feebly obsolete microreticulation at intervals.

Underside ferruginous, almost micro-reticulate and covered with white pubescence. Punctures of mentum sparsely scattered and not deeply impressed. Prosternum with a medio-longitudinal carina. Mesosternum strongly elevated and marking a triangular plate with a broad point in anterior portion. Metasternum progressively elevated towards posterior portion at middle, without glabrous area. First ventrite with a mediolongitudinal carina which is about 1/ 2 in length of the total. Apical margin of fifth ventrite not emarginated at middle. Legs slender. Pubescence of profemora about 1/ 3 in length from base, meso- and metafemora about 1/ 4 of the total length.

Aedeagus ( Fig. 6 ). 1.15 mm long, median lobe distinctly widened from base to middle part and then gradually narrowed toward distal part, but ending with a pointed apex, distinctly shorter than parameres; basal third of parameres robust, then narrowed toward apical part, the apical third distinctly narrowed and medially arched, encircling the broadest part of the median lobe.

Females. Body length 3.5–3.6 mm, width 2.2–2.3 mm, larger than males. Head and elytra almost black, pronotum and beneath dark brown.

Distribution. China (Guangxi Autonomous Region).

Etymology. Named after the type locality, Yülin Prefecture, in Guangxi Autonomous Region.

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.