Helochares songi, Jia & Tang, 2018

Jia, Fenglong & Tang, Yu-dan, 2018, A revision of the Chinese Helochares (s. str.) Mulsant, 1844 (Coleoptera, Hydrophilidae), European Journal of Taxonomy 438, pp. 1-27 : 3-6

Helochares songi sp. nov.

urn:lsid:zoobank.org:act:2B1792C1-5D59-46B2-AE98-3440BA2FED57

Figs 1–8 , 48–49

Diagnosis

Length 4.8–5.3 mm, width 2.6–2.9 mm. Dark brown or black ( Fig. 1 ), clypeus uniformly dark brown to black ( Fig. 4 ), anterior half of lateral margin of pronotum yellowish brown ( Figs 1, 3–4, 6 ), elytra uniformly dark brown to black ( Fig. 3 ). Dorsum with uniform dense and coarse ground punctures. Clypeus moderately expanded laterally, with somewhat rounded lateral margin, clearly impressed in front of eyes ( Fig. 4 ). Maxillary palps ca 1.2× as long as width of head, dark brown to black, each palpomere with light colour apically ( Figs 1–2, 4 ). Pedicel subequal in length to antennomeres 3–6 combined. Submentum with a small glabrous area medially and with a few coarse punctures laterally ( Fig. 5 ). Elytra almost parallel from base to posterior third, somewhat explanate laterally, with distinct systematic punctures ( Fig. 3 ). Mesoventrite with a low transverse ridge medially and a low longitudinal carina ( Fig. 7 ). Metaventrite without glabrous area medially. Femora densely pubescent except for apical eighth ( Figs 2, 8 ). Aedeagus slender, length of paramere ca 10 × as long as width of apex ( Fig. 48 ), subparallel, apex with a small tooth inwards ( Figs 48–49 ); apex of median lobe slightly overlapping parameres; basal strut of median lobe long, ca ¼ × as long as parameres ( Fig. 48 ).

Etymology

The specific name is given in honor of Keqing Song, the collector of the type specimens.

Material examined

Holotype

CHINA: 1 ♂, Guangxi Province, Shiwandashan, Nalin River , 316 m a.s.l., in water at edge of upper river, 21 Jul. 2011, Keqing Song leg. ( SYSU).

Paratypes (77 spec., BMNH, KMNH, NMPC, SYSU)

CHINA: Guangxi: 2 ƋƋ, 4 ♀♀, 15 spec., same collection data as for holotype; 3 spec., Shiwandashan, Forest Park, 239 m a.s.l., edge of upper river, 19 Jul. 2011, Keqing Song leg.; 11 spec., Shiwandashan, Forest Park, edge of river, 17 Aug. 2011, Keqing Song leg.; 3 spec., Shiwandashan, Forest Park, 221 m a.s.l., in water at edge of lower stone river, 12 Jul. 2011, Keqing Song leg.; 20 spec., Shiwandashan, 430 m a.s.l., edge of Nalinhe River (in water), 21 Jul. 2011, Keqing Song leg.; 19 spec., Shiwandashan, 269 m a.s.l., edge of river outside Forest Park, 20 Jul. 2011, Keqing Song leg. ( BMNH, KMNH, NMPC, SYSU).

Description

FORM AND COLOUR. Body oval, length 4.8–5.3 mm, width 2.6–2.9 mm, moderately convex. Head dark brown to black. Pronotum dark brown to black, anterior half with narrow yellowish brown lateral margins ( Figs 1, 3–4, 6 ). Elytra uniformly dark brown to black ( Figs 1, 3 ). Maxillary palps dark brown to black, each palpomere light yellowish brown apically ( Figs 1–2, 4 ). Labial palpomeres yellow to yellowish brown. Antennae yellowish brown, club with dense yellow setae. Ventral side dark brown or black ( Fig. 2 ), legs with same colour as ventral side, but with reddish to yellowish brown tarsomeres ( Fig. 2 ).

HEAD. Labrum with fine and dense punctures, smooth between punctures, anterior margin broadly emarginate. Clypeus broad, anterior margin clearly broadly emarginate, moderately expanded in front of eyes, with somewhat rounded lateral margin ( Fig. 4 ), clearly impressed in front of eyes ( Fig. 4 ). Ground punctures on clypeus coarser and sparser than those on labrum, surface smooth between punctures. Systematic punctures on clypeus almost same size as ground punctures. Eyes of moderate size, clearly emarginate anteriorly ( Figs 1, 4 ), separated by ca 4.0–4.1 × the width of one eye. Frons with slightly coarser and stronger punctures than on clypeus, with clear systematic punctures. Maxillary palps long and slender, ca 1.1–1.2 × as wide as head, second and third palpomeres curved inwards, apical palpomere almost as long as penultimate, asymmetrical ( Fig. 4 ). Antennae with 9 antennomeres, scape ca 1.5× as long as pedicel, pedicel subequal in length to antennomeres 3–6 combined, club loosely segmented, with dense pubescence. Mentum ca as wide as long, subquadrate, with deep v-shaped impression anteromedially, with coarse punctures and wrinkles posteriorly ( Fig. 5 ). Submentum with a small glabrous area medially and with a few coarse punctures laterally. Maxilla with coarse punctures, smooth between punctures.

THORAX. Pronotum ca 2× as wide as long, widest posteriorly, posterolateral margins broadly round, anterior margin smooth, with a very fine transverse groove, lateral margin with stronger groove, posterior margin without such groove; posterior margin almost straight. Ground punctures slightly coarser than those on head, systematic punctures on pronotum distinct, almost of same size as ground punctures ( Figs 4, 6 ). Prosternum bulging in middle, not carinate, pubescent, with transverse groove ( Fig. 5 ), protruding anteriorly. Mesoventrite with a low transverse ridge medially, which does not bear an elevated tooth or projection but with long setae ( Fig. 7 ); behind ridge with a low longitudinal carina. Metaventrite pubescent, with somewhat convex middle portion, without glabrous area. Metepisterna ca 3.5× as long as wide, subparallel. Scutellum triangular, with similar punctures to elytra. Elytra almost parallel from base to posterior third, somewhat explanate laterally, ground punctures similar to those on pronotum, with 3 distinct rows of systematic punctures ( Fig. 3 ), without sutural stria; epipleuron very broad anteriorly, reaching posterior margin of first visible abdominal sternite, with sparse, coarse punctures. Femora densely pubescent, with apical eighth glabrous ( Figs 2, 8 ). Metatarsomeres with dense white hairs ventrally and a few long swimming hairs dorsally. Claws of moderate size, rather strongly curved.

ABDOMEN. All visible abdominal ventrites with dense pubescence; first ventrite not carinate ( Figs 2, 8 ).

AEDEAGUS. Slender, length of parameres ca 10 × as long as width of apex, subparallel, a little expanded subapically and round apically ( Fig. 48 ), apex with a small, inwardly directed tooth ( Figs 48–49 ); median lobe slightly protruding beyond parameres, gradually narrowed apically, apex ca 0.5× as wide as apex of parameres; basal strut long, ca ¼ × as long as parameres ( Fig. 48 ).

Differential diagnosis

This species is very similar to H. fuliginosus d’Orchymont, 1932 , but may easily be distinguished from the latter by its larger size (3.6–4.3 mm in H. fuliginosus ), lateral margin of clypeus and elytra with same colour as disc ( Fig. 4 ), pronotum and elytra more coarsely punctate, and maxillary palps dark brown or black, each palpomere with light colour apically ( Figs 4–5 ). Aedeagus slender, parameres ca 10 × as long as width of apex ( Fig. 48 ), apex with a small inwardly directed tooth ( Figs 48–49 ); median lobe slightly projecting beyond parameres apically ( Fig. 48 ). It can be distinguished from H. atropiceus Régimbart, 1903 , H. ciniensis Hebauer, 1999 and H. taprobanicus Sharp, 1890 , occurring in the Oriental, by its slender aedeagus, parameres ca 10× as long as width of apex, without branches, not concave outside, apex with a small inwardly directed tooth ( Figs 48–49 ). Hebauer (1995) described Helochares fulgurans based on a unique female from Thailand. Helochares songi sp. nov. can be distinguished from H. fulgurans by its larger size (3.5 mm in H. fulgurans ), dark colour (bright yellow brown, only dark between eyes, with two dark basal spots on pronotum in H. fulgurans ) and maxillary palps dark brown or black, each palpomere with light colour apically (yellow in H. fulgurans ). From H. vitalisi d’Orchymont, 1919 ( Fig. 45 ) it differs in having the head, pronotum and elytra with coarser punctures (ground punctures very fine in H. vitalisi ), each maxillary palpomere with light colour apically, clypeus moderately expanded laterally, with somewhat rounded lateral margin, clearly impressed in front of eyes (clypeus not expanded laterally and not impressed in front of eyes in H. vitalisi ) and elytra almost parallel from base to posterior third (widest at middle in H. vitalisi ), somewhat explanate laterally (not explanate in H. vitalisi , as in Enochrus ).

Biology

Lives along the sides of rivers with a sandy bottom and stagnant water. The female carries the egg case under the abdominal ventrites.

Remarks

The density is very high at the type locality, but no specimen was collected at light in July. It is probable that this species can be collected at light during its reproductive period.

Distribution

China (Guangxi), so far only known from the Shiwandashan National Park and its surroundings.

Figures

Figs 1–8. Helochares songi sp. nov. 1–3. Habitus. 1. Dorsal. 2. Ventral. 3. Lateral. 4. Head and pronotum. 5. Head and prosternum. 6. Pronotum, lateral. 7. Mesoventrite. 8. Abdomen.

Figs 47–55. Aedeagi in species of Helochares Mulsant, 1844. 47. H. fuliginosus d’Orchymont, 1932. 48–49. H. songi sp. nov. 50–51. H. atropiceus Régimbart, 1903. 50. From Guangxi. 51. From Hong Kong. 52. H. pallens (MacLeay, 1825). 53–55. H. obscurus (Müller, 1776). 53. From Xinjiang. 54–55. After Hansen (1987).

Figs 41–46. – 41–42. Helochares pallens (MacLeay, 1825). Elytra. 41. Dorsal. 42. Ventral. 43, 45. Paratype of H. vitalisi d’Orchymont, 1919. 43. Data of labels. 45. Habitus, dorsal. 44, 46. Paratype of H. fuliginosus d’Orchymont, 1932. 44. Data of labels. 46. Habitus, dorsal.