Helochares (Hydrobaticus) wuzhifengensis, Dong & Bian, 2021

Dong, Xue & Bian, Dongju, 2021, Three new species and two new records of Helochares (Hydrobaticus) MacLeay 1871 from China (Coleoptera: Hydrophilidae: Acidocerinae), Zootaxa 4950 (1), pp. 166-180 : 170-171

Helochares (Hydrobaticus) wuzhifengensis sp. n.

( Figs. 5–8 )

Material examined. Holotype (IAECAS): 1 male: “ CHINA: Jiangxi Province, Ganzhou City, / Shangyou County, Wuzhifeng Town , | 25°57’N, 114°05’E, 554 m, / 2009.10.05, leg. Bian &Tong”.

Diagnosis. This new species is similar to Helochares nipponicus in habitus, but can be distinguished by the following characteristics: (1) elytra gradually narrowed from midpoint ( Fig. 5 ); broadly rounded along posterior half in H. nipponicus ( Fig. 15 ); (2) elytra and ventral side lighter than H. nipponicus in color; (3) aedeagus ( Fig. 7 ) with median lobe elongate, gradually widening towards apex, distal 0.25 narrowing to the apex. Median lobe slightly longer than parameres. Membranous inner sac with several small dentiform bulges on distal 0.2 to distal 0.4 ( Fig. 7a ).

Description. Habitus as in Figs. 5–6 . BL: 4.5 mm, BW: 2.2 mm. Body oval, moderately convex. Head, pronotum, elytra and ventral side dark brown, apex of tarsal claws black.

Head ( Fig. 5 ). Labrum black, sparsely punctate, anterior margin straight. Clypeus dark brown, broad, densely punctate, anterior margin broadly emarginate; area in front of eyes with a few sparse punctures, moderately expanded laterally. Eyes rounded in dorsal view, slightly bulging, somewhat prominent. Frontoclypeal suture distinct. Systematic punctures small and distinct. Antennae with nine antennomeres, yellowish-brown; club loosely articulated, densely pubescent. Maxillary palpi moderately long and slender, about 1.2 times long as the width of head, yellow, second palpomere curved inwards. Mentum and submentum dark brown, with coarse punctures and wrinkles.

Thorax ( Fig. 5–6, 8 ). Maximum width of pronotum about twice as its length; distinctly and densely punctate; anterior and posterior angles broadly rounded. Anterior margin slightly projected anteriad in mid-length; a median black mark near anterior margin. Lateral margin yellowish-brown, with large punctures on ventral surface. Posterior margin mildly corrugate, with a transverse groove; a pair of small pits which overlap with black marks in posterior area ( Fig. 5 ). Prosternum ( Fig. 6 ) slightly bulging at the middle, not carinate, protruding posteriorly; pubescent and rugulose, with fine and dense punctures. Mesoventrite strongly convex at postmedian area. Metaventrite pubescent, with fine punctures, somewhat convex at middle portion, convex part with long and dense setae. Elytra ( Fig. 8 ) together slightly wider than pronotum, subparallel in basal 0.6, then gradually narrowed posteriorly; with scutellary stria and ten impressed series of punctures; interstriae with small and dense punctures, serial punctures distinctly larger and deeper than the interstrial punctures; interstriae wide and flat; large punctures on underside of elytra usually visible from dorsal view on distal quarter. Scutellum shield triangular, without punctures.

Legs. Femora dark brown, tibiae and tarsi brown, apex of tarsal claws black. Femora densely pubescent with apical fifth glabrous. Tarsi with dense white setae.

Abdomen ( Fig. 6 ). All visible ventrites with dense pubescences and fine punctures; apex of ventrite five strongly emarginate.

Aedeagus ( Fig. 7 ). Elongated, 1.2 mm long. Basal piece very short, about 0.17-times of aedeagus length. Median lobe gradually widened from base to apex, distal 0.25 narrowed, slightly longer than parameres, apex narrowly rounded; Membranous inner sac with several small dentiform bulges on distal 0.2 to distal 0.4 ( Fig. 7a ). Median lobe with two strong spines medially ( Fig. 7b ).

Distribution. Known only from the type locality in Jiangxi Province, China.

Etymology. Named after the type locality, Wuzhifeng Town, Jiangxi Province, China.

Habitat ( Fig. 26 ). Slow flowing stream, with pebbles, silt, mossy stones, deadwood and sides with fireweed.

Figures

FIGURES 5–8. Helochares (Hydrobaticus) wuzhifengensis sp. n. 5–6. Habitus. 5. Dorsal view. 6. Ventral view. 7. Aedeagus (a. Dentiform bulges; b. Strong spines). 8. Posterior half of elytra.

FIGURES 13–16. Habitus. 13, 14. Helochares (Hydrobaticus) minor; 15, 16. Helochares (Hydrobaticus) nipponicus. 13, 15. Dorsal view; 14, 16. Ventral view.

FIGURES 25–27. Habitat. 25. Wanquan Town, Qionghai City, Hainan Province (Helochares (Hydrobaticus) hainanensis sp. n.); 26. Wuzhifeng Town, Ganzhou City, Jiangxi Province (Helochares (Hydrobaticus) wuzhifengensis sp. n.); 27. Mangkuan Village, Baoshan City, Yunnan Province (Helochares (Hydrobaticus) tengchongensis sp. n.).