Helochares distinctus Jia & Tang, 2021

Yang, Zhenming, Jia, Fenglong, Tang, Yudan & Jiang, Lu, 2021, Two new species of Helochares, with additional faunistic records from China (Coleoptera, Hydrophilidae, Acidocerinae), ZooKeys 1078, pp. 57-83 : 57

Helochares distinctus Jia & Tang sp. nov.

Figs 3-4 , 5 , 7 , 10-20 , 21-23 , 27-28

Material examined.

Holotype: male, Jiangxi , Jing’an County, Zaodu town , Nanshan, 29°01'N, 115°16'E, 315m, 2.viii.2015, Renchao Lin and Yudan Tang leg. Paratype: 1 male, Hunan , Guidong County, Bamianshan Nature Reserve, 25°58'21"N, 113°42'37"E, 973 m, 2015.vi.15, Renchao Lin and Yudan Tang leg.

Differential diagnosis.

This species is very similar to H. lentus Sharp, 1890, H. densus Sharp, 1890, H. sauteri d’Orchymont, 1943 and H. hainanensis Dong & Bian, 2021 in size, form and other morphological characters, but it is very easy to distinguish from all known species by aedeagal features. Aedeagus (Figs 27-28 ) with median lobe slightly shorter than parameres, nearly rhombic, apex with a globular structure with a cluster of apical spines and with a long baseball-bat-shaped branch medially, membranous inner sac with some strong spinous protrusions. Helochares distinctus Jia & Tang, sp. nov. can easily be distinguished from H. guoi Jia & Yang, sp. nov. by its larger size, median lobe of the aedeagus with a globular structure with a cluster of spines apically and with a long baseball-bat-shaped branch medially; membranous inner sac with some less strongly spinous protrusions.

Description.

Form and colour (Figs 3 - 5 , 7 ). Body length 5 mm, body width 2.6 mm, oval, moderately convex. Dorsum of head, pronotum, elytra and clypeus yellow-brown, labrum dark brown. Antennae yellow-brown with club black. Maxillary palps uniformly yellow-brown. Labial palps yellow, not darkened apically. Venter, including legs, blackish brown, tarsomeres yellow-brown.

Head. Antennae with scape ca as long as antennomeres 2 and 3 combined (Figs 10-11 ). Maxillary palps ca 1.25 × as long as of width of head anterior to eyes; apical segment asymmetrical, slightly shorter than the penultimate in length (Fig. 12 ). Clypeo-labral margin straight medially. Labrum, frons and clypeus with systematic punctures (with setae) same size as ground punctures; frons and clypeus with ground punctation dense and coarse, distance between punctures 0.5-1.2 × width of one puncture. Mentum subquadrate, with anterior margin strongly emarginate, slightly depressed medially, surface with some oblique wrinkles (Fig. 13 ).

Thorax. Ground punctation on pronotum and elytron similar to that on head, distance between punctures 0.5-1.2 × width of one puncture; anterior margin without very fine bead. Elytron with short scutellary series of punctures and 10 striae, punctures in striae distinctly coarser than ground punctures; systematic punctures as coarse as punctures in striae. Prosternum moderately elevated medially, not tectiform or carinate medially (Fig. 15 ), with a transverse groove anteriorly. Mesoventrite with a small posteromedial tubercle, not carinate medially (Fig. 16 ). Metaventrite without glabrous area posteromedially. Femora densely pubescent except at apex (Fig. 17 ). Meso-, and metasomeres 1 to 4 with dense long setae ventrally, posterior tarsomeres with a fringe of long swimming-hairs dorsally. Protarsal claws in male somewhat stronger and a little angularly curved, bearing a blunt basal tooth; mesotarsal claws as protarsals, but only moderately curved with a blunt tooth; metatarsal claws only moderately curved, with a blunt basal tooth (Figs 18 - 23 ).

Abdomen. Ventrites uniformly and densely pubescent. Fifth (apical) abdominal ventrite with apical emargination fringed with stiff yellowish setae (Fig. 14 ).

Aedeagus (Figs 27-28 ). Phallobase ca 0.24 mm; paramere ca 1.0 mm, widest at the apical quarter, apical quarter slightly narrowed towards to the apex, apex rounded; median lobe slightly shorter than the parameres, ca 0.91 mm, nearly rhombic, apex with a globular structure with a cluster of apical spines and with a long baseball-bat-shaped branch medially; membranous inner sac with some strong spinous protrusions; basal apophyses about one third as long as the median lobe, ca 0.35 mm.

Remark.

The antennal pedicel of the male paratype also bears a long fungus as in H. guoi Yang & Jia sp. nov. (Fig. 10 ). However, the male holotype of this species lacks such a structure, although only the scape and pedicel remained on the right antenna (Fig. 11 ) and the left antenna was lost.

Etymology.

Latin " Helochares distinctus ", referring to the antennae and aedeagus with clearly different characters from other known species.

Distribution.

China (Jiangxi, Hunan).

Habitat.

Living on edge of stagnant water pool.

Additional faunistic data.

Fig. 65

Figures

Figure 65. Distribution map of Helochares species in China.

Figures 1 - 4. Habitus 1 - 2 Helochares guoi Yang & Jia, sp. nov. 1 dorsal view 2 ventral view 3 - 4 Helochares distinctus Jia & Tang, sp. nov. 3 paratype, dorsal view 4 holotype, dorsal view.

Figures 5 - 7. Habitus 5 Helochares distinctus Jia & Tang, sp. nov.: ventral view 6 - 7 head, dorsal view 6 Helochares guoi Yang & Jia, sp. nov. 7 Helochares distinctus Jia & Tang, sp. nov ..

Figures 8 - 20. 8 - 9 Helochares guoi Yang & Jia, sp. nov. 8 antennae 9 maxillary palp 10 - 20 Helochares distinctus Jia & Tang, sp. nov. 10 the antennae of fig 3 11 the antennae of fig 4 12 maxillary palp 13 mentum 14 apex of fifth abdominal ventrite 15 prosternum 16 mesoventrite 17 metaventrite 18 protarsomeres 19 mesotarsomeres 20 metatarsomeres.

Figures 21 - 28. 21 - 23, 27 - 28 Helochares distinctus Jia & Tang, sp. nov. 24 - 26 Helochares guoi Yang & Jia, sp. nov. 21 protarsomeres 22 mesotarsomeres 23 metatarsomeres 24 - 28 aedeagus 24 ventral view 25 lateral view 26 dorsal view 27 dorsal view 28 lateral view.