Pelthydrus (s. str.) ruiliensis, Zhu & Ji & Bian, 2018

Zhu, Bingyue, Ji, Lanzhu & Bian, Dongju, 2018, A new species and a new record of Pelthydrus Orchymont, 1919 from Yunnan, China (Coleoptera: Hydrophilidae: Hydrophilinae), Zootaxa 4438 (1), pp. 189-194 : 192-194

Pelthydrus (s. str.) ruiliensis sp. nov. ( Figs 1–2 , 5 , 8 )

Type material. Holotype (IAECAS) male: “ CHINA: Yunnan Province, Ruili City, Dayingjiang National Scenic Area, Moli Management Office , 24°06'N, 98°00'E, 127 m, 17. 10. 2016, leg Wang, Peng & Sun” . Paratypes: 4 males (IAECAS), same data as holotype .

Diagnosis. This species is similar to Pelthydrus sculpturatus Orchymont , but can be distinguished by its thinner body shape and the different shape of aedeagus: the parameres of new species are significantly longer than the phallobase, while the latter is the opposite; and the position of gonopore also differs.

Description. Habitus as in Figs. 1–2 . BL: 2.70–2.95 mm; BW: 1.50–1.65 mm. Body elongated oval, slightly convex, semicircular in posterior portion, surface shiny, dark black; antennae, lateral margins of pronotum, labial palpi, maxillary palpi, tibiae and tarsi yellowish brown. Head trapezoidal, about 1.6 times as wide as long; surface microreticulate, with evenly distributed median-sized punctures and yellowish brown setae sparsely distributed around eyes; frontoclypeal suture distinct; anterior margin of clypeus somewhat arched in the middle. Pronotum trapezoidal, about 1.4 times as wide as long, anterior corners rounded, the lateral margins nearly straight; surface microreticulate around corners; median-sized ground punctures evenly distributed; yellowish brown setae sparsely distributed along lateral margins of anterior half. Elytra about 2.6 times as long as wide; broadest part at basal 0.4, then gradually narrowed posteriorly, ending with narrowly rounded apices that do not meet at midline; ground punctures which slightly larger than those on head densely distributed, serial punctures on both sides of elytra. Ventral surface reddish brown, mentum dark brown, somewhat rugulose; prosternum reddish brown with a median longitudinal carina; Mesoventrite with apically slightly rounded triangular plate and median longitudinal carina; metaventrite with a posterior teardrop-shaped, flat and smooth glabrous area; first sternite with a medial longitudinal carina not reaching posterior margin. Aedeagus ( Fig. 5 ). 0.52 mm long, nearly parallel-sided, parameres about 1.4 times as long as phallobase; median lobe wide, gradually narrowing from base, gonopore located at apex; parameres exceeding median lobe, with apex oblique and truncated, inner margin shorter than outer margin.

Distribution. Yunnan Province, China.

Etymology. Named after the type locality, Ruili City, Yunnan Province, China.

Habitat. As shown in Fig. 7 . Small stream, unpolluted, sand, shatters, bank with sand, shrubs and grass.

Remarks. A newly generated partial sequences of cytochrome oxidase subunit I (COI) is deposited in GenBank under accession number MG554385 .

Figures

FIGURE 7. Distribution, Pelthydrus ruiliensis sp. nov. (○), Pelthydrus madli (Δ).

FIGURE 8. Stream in Moli Falls, Yunnan Province, China. Habitat of Pelthydrus ruiliensis sp. n.. Photograph by Y. Peng.

FIGURES 1–4. Habitus, 1–2: Pelthydrus ruiliensis sp. nov. 3–4: Pelthydrus madli Schönmann. 1, 3 dorsal view; 2, 4 ventral view. Scale=1 mm.

FIGURES 5–6. Aedeagus, dorsal view; 5. Pelthydrus ruiliensis sp. nov. (holotype); 6. Pelthydrus madli Schönmann. Scale=0.1 mm.