Pelthydrus (s.str.) schoenmanni, Zhu & Ji & Bian, 2019

Zhu, Bingyue, Ji, Lanzhu & Bian, Dongju, 2019, A new species of Pelthydrus (s. str.) Orchymont, 1919 from Yunnan, China (Coleoptera: Hydrophilidae: Hydrophilinae: Laccobiini), Zootaxa 4614 (3), pp. 593-599 : 594

Pelthydrus (s.str.) schoenmanni sp. nov.

Figs. 1–2 , 3A, 4–5

Type material. Holotype (male): “ CHINA: Yunnan Province, Baoshan City, Longyang District, Lujiang Town , Shiti Village , Bawan River , 24°56'N, 98°49'E, 127 m, 10. 20. 2018, leg. Peng, Zhu & Dong” . Paratypes (5): 4 males and 1 female, same data as holotype. The holotype and paratypes are deposited in the Institute of Applied Ecology , Shenyang, Chinese Academy of Sciences (IAECAS) .

Diagnosis. This species is similar to Pelthydrus vietnamensis Schönmann , but it can be differentiated by its smooth elytral surface and the different shape of aedeagus ( Fig. 3 ): the punctures on the elytra of the new species are smaller and fine, while those of P. vietnamensis are rough; and the parallel shaped distal half of the parameres of the new species is distinctly longer; in addition, the gonopore of the former is situated in apical 1/5 of the median lobe, then suddenly narrowed, ending with a sharply pointed apices, and that of the latter is located in apical 1/7 of the median lobe, then slightly narrowed, ending with a blunt pointed apices.

Description. Habitus as in Fig. 1A . BL: 3.65–3.85 mm; BW: 2.25–2.35 mm. Broadly oval and distinctly convex, semicircular in posterior portion, complete surface shining, black; antennae, lateral margins of the pronotum, labial, maxillary palpi, tibiae and tarsi yellow brown.

Head trapezoidal ( Fig. 1B ), about 1.84 times as wide as long; surface microreticulate, with densely distributed small punctures and yellowish-brown setae sparsely distributed around eyes; frontoclypeal suture distinct; anterior margin of clypeus truncated.

Pronotum trapezoidal ( Fig. 1C ), about 1.65 times as wide as long, anterior corners angulated, posterior corners broadly rounded; lateral margins straight with narrowly ridged, anterior margin somewhat arched at middle; surface microreticulate around corners; median-sized ground punctures evenly distributed, a little bigger than that on head; yellowish brown setae sparsely distributed along lateral margins of anterior half.

Elytra about 2.38 times as long as wide; broadest part at basal 3/10, then gradually narrowed posteriorly, ending with narrowly rounded apices that do not meet at midline; fine and ground punctures which smaller than those on pronotum densely distributed, three slightly deeper punctate striae on both sides of elytra (Fig. 1D). Ventral surface yellow brown (Fig. 2A), mentum dark yellow brown (Fig. 2B), with median-sized punctures sparsely distributed, surface shining and somewhat rugulose; prosternum yellow brown with a median longitudinal carina; mesoventrite with apically significantly rounded triangular plate and median longitudinal carina (Fig. 2D); metaventrite highly raised, with small punctures and yellowish brown setae evenly distributed; first sternite with a medial longitudinal carina not reaching posterior margin (Fig. 2C). Aedeagus (Fig. 3A). 1.32 mm long, outline nearly parallel sided, parameres about 0.73 times as long as the length of the phallobase; median lobe gradually widened from base toward apical 1/5 where the gonopore is situ- ated, then abruptly narrowed, tapering to an acute apex; parameres extending beyond the apex of the median lobe; basal half of parameres robust, abruptly narrowing at middle with distal half nearly parallel sided. Distribution. Yunnan Province, China. Etymology. The late Doctor Heinrich Schönmann (Vienna) was an entomologist who studied Hydrophilidae that contributed substantially to our knowledge of the genus Pelthydrus. We name the new species in his honor to express our nostalgia and admiration for him. Habitat. As shown in Fig. 4. A small stream, unpolluted, sand, gravel, bank with sand, shrubs and vegetation.

Figures

FIGURE 1. Views of Petlhydrus schoenmanni. A: Habitus, in dorsal view; B: Head, in dorsal view; C: Pronotum, in dorsal view; D: Elytra, in lateral view. Scales=0.5 mm.

FIGURE 2. Views of Petlhydrus schoenmanni. A: Habitus, in ventral view; B: Head, in ventral view; C: The first sternite with a medial longitudinal carina; D: The prosternum and mesoventrite. Scales=0.5 mm.

FIGURE 3: Aedeagus, in dorsal view; A. Pelthydrus schoenmanni sp. nov. (holotype); B. Pelthydrus vietnamensis Schönmann. Scale=0.5 mm.