Pelthydrus grossus, 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 : 59-60

Pelthydrus grossus sp. nov.

( Figs. 1–2 )

Type material. Holotype (IAECAS) male: " CHINA: Yünnan, Xishuangbanna/ 1500 m. 10. VI. 1999 / leg. Wang & Wei". Paratypes: 4 exs. (IAECAS), the same data as holotype; 2 exs. (IAECAS), CHINA: Yünnan, Xishuangbanna ( CWBS 359); 1 ex. (IAECAS), CHINA: Yünnan, Xishuangbanna ( CWBS 379); 1 ex. (IAECAS), N-Laos: Prov. Lg. Nam Tha, ca. 20 km SE Muang Sing, 950 m, 12/13 June 1996, Leg. Schillhammer; 50 exs. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 354); 10 exs. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 359); 19 exs. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 360); 6 exs. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 365); 10 exs. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 367); 12 exs. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 370); 1 ex. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 377); 15 exs. ( NMW), CHINA: Yünnan, Xishuangbanna ( CWBS 379); 7 exs. ( NMW), WDS–A–1044/ THAILAND: Chiang Mai/ Doi Suthep National Park/ Montatharn Falls, 24.III.1994 / leg. William D. Shepard; 2 exs. ( NMW), THAILAND (4): Chiang Mai/ Doi Suthep National Park/ Montatharn Falls, 700–800 m / leg. H. Zettel, 2.XI.1995; 4 exs. ( NMW), THAILAND (7): Chiang Mai/ Doi Suthep N.P., Doi Suthep/ river between Ruesse Cave and/ Radiostation, 900–1000 m / 05.XI.1995, leg. H. Zettel; 1 ex. ( NMW), N-THAILAND: Chiang Mai/ Doi Suthep NP, 1000 m / Sai Yoi Wf., 26.2.1998 / leg. P. Mazzoldi (2); 1 ex. ( NMW), N-THAILAND: Chiang Mai/ 12 km W Chom Thong/ Mae Klang riv./ 27.12. 1998, 550 m/ leg. P. Mazzoldi (7); 2 exs. ( NMW), N-THAILAND: Nan, 2.1.1999 / Doi Phu Ka NP, 1400 m / 1 km after Park HQ/ leg. P. Mazzoldi (24); 7 exs. ( NMW), N-THAILAND: Nan, 3.1.1999 / Doi Phu Ka NP, 1400 m / nr. Huai Nam Dan vill./ leg. P. Mazzoldi (26); 1 ex. ( NMW), N-THAILAND: Nan, 2.1.1999 / Doi Phu Ka NP, 1240 m / Ton Tong Waterfall/ leg. P. Mazzoldi (27); 2 exs. ( KSEM), THAILAND: Chiang Mai Province/ Doi Inthanon Natl. Park, 1380 m / Siriphum Waterfall (upper)/ 18°32’N 98°31’E, 2.3.2002, L-249/ colls: Vitheepradit, Kirawanich; 5 exs. ( KSEM), THAILAND: Nan Prov./ Doi Phu Ka Nat. Pk., L-291/ Nam Tok Ton Thang, 13.3.2002 / 19°12’N 101°04’E, 900 m / Vitheepradit, Kirawanich; 1 ex.

( KSEM), THAILAND: Mae Hong Son/ Province, Namtok Maw Pang/ 19°22’N 98°22’E; 850 m / 19.3.2002, L-305/ Sites, Vitheepradit, Kirawanich; 1 ex. ( KSEM), THAILAND: Chiang Mai Prov./ Doi Inthanon N. P.; Siriphum/ WF, level 2, 1460 m, L-314/ 18°32’N 98°31’E, 21.3.2002 / Vitheepradit, Kirawanich; 4 exs. ( KSEM), THAILAND: Nan Province/ Doi Phuka Natl. Pk., Namtok/ Ton Thong, 19°12’N 101°04’E / 900 m; 21. April 2003; L-472/ AV, Prommi, Setaphan; 2 exs. ( NMW), N-LAOS: Prov. Lg. Nam Tha/ ca. 20 km SE Muang Sing/ 12-13. 6. 1996, 950 m/ leg. Schillhammer (25); 6 exs. ( NMW), N LAOS / Luang Namtha env./ 800-1200 m / May 1997; 3 exs. ( NMW), Ph. Pan (Mt.)/ Houaphan Prov./ LAOS / 28. IV – 6. V. 2002 / leg. H. Yoshitomi.

Diagnosis. This species is similar to P. dudgeoni and P. vietnamensis , but can be easily distinguished by its larger size, robust parameres and narrowed median lobe of aedeagus from the former; by its broad anterior corners of pronotum and different shape of the paramere from the latter.

Description. Body length 3.8–4.1 mm, width 2.3–2.6 mm; oval and strongly acute in apical portion. Mostly black, tibiae, and lateral sides of head and pronotum testaceous. Antennae, labial and maxillary palpi, and tarsi yellowish-brown.

Head trapezoidal, anterior corners acute, about 1.6 times as wide as long, distinctly narrower than pronotum, densely and strongly punctuate, with innersides of eyes distinctly wrinkled. Labrum transverse with sparse and small punctures. Antennae 8-segmented, terminal three segments forming a club, with approximate ratio of 2nd, 3rd, 4th segments 10: 7: 20 in length.

Pronotum trapezoidal, about 2.4 times as wide as long, lateral sides sub–paralleled, anterior and lateral sides narrowed and feebly bordered, densely and strongly punctuate, punctures a little smaller than on head. Scutellum small and triangular, with medium-sized punctures sparsely scattered.

Elytra broadest at one third from base, slightly narrowed towards anterior portion and strongly narrowed posteriorly, about 1.2 times as long as wide, slightly broader than pronotum, lateral sides broadly bordered and strongly reflexed.

Ventral side scattered with dense punctures covered with white pubescence. Mentum with posterior 4/5 sparsely and strongly punctuate. Prosternum with a medio-longitudinal carina ending with a sharp point anteriorly. Mesosternum strongly elevated and forming a triangular plate posteriorly carinate at middle in distal 1/2. Metasternum strongly elevated at middle, anterior 1/3 with medio-longitudinal carina. First ventrite with medio-longitudinal carina which almost reaches the hind margin. Legs slender, profemora testaceousbrown with pubescence in basal half, meso- and metafemora darker than profemora with pubescence in basal 1/4 and basal 1/5, respectively. Claws slender.

Aedeagus ( Figs. 1–2 ): 0.85 mm (holotype), 0.8 mm (paratype from Laos). Median lobe distinctly narrowed from base towards apical part; parameres very robust ending with pointed apices.

Females: Body length 4.0– 4.3 mm, width 2.6–2.7 mm; dorsally darker than male. Underside almost black, profemora darker than in males.

Distribution. China (Yünnan Province), Laos, Thailand.

Etymology. The specific name comes from the Latin word “ grossus ” = “thick” and refers to the broad parameres of aedeagus.

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.