Helochares atropiceus Régimbart, 1903

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 : 9-12

Helochares atropiceus Régimbart, 1903

Figs 18–25 , 50–51

Helochares (s. str.) atropiceus Régimbart, 1903: 53 (specific rank confirmed by Hebauer 2001: 11; not a synonym of H. taprobanicus Sharp, 1890 , as in Hansen 1999: 163).

Helochares (Helochares) ohkurai Satô, 1976: 21 (synonymyzed by Hebauer 2001: 11).

Diagnosis

Size 5.4–6.7 mm. Dorsum with distinctly sparser and finer punctures than in H. songi sp. nov. ( Fig. 18 ). Labrum and clypeus with distinct systematic punctures. Clypeus never impressed in front of eyes ( Figs 20–21 ). Eyes not emarginate anteriorly ( Figs 20–21 ). Maxillary palpi ca 1.6× as long as width of head, each palpomere uniformly yellowish brown ( Figs 18, 21 ). Antennae with pedicel distinctly shorter than antennomeres 3–6 combined. Submentum without a small glabrous area medially and with even, dense, coarse and strong punctures except extreme posterior portion ( Fig. 22 ). Pronotum and elytra finely punctate. Mesoventrite with a stout, backwardly pointing projection, rising to level of mesocoxae, apex of the projection with a few long setae ( Fig. 24 ). Metaventrite without glabrous area medially. Femora densely pubescent except apical eighth ( Figs 19, 25 ). Parameres somewhat wider than widest part of median lobe, each paramere with 3 branches: inner branch short and strongly curved inwards; median branch knife-formed, sharp apically, slightly longer than outer branch; outer branch narrower than other two branches, apical third curved inwards, sharp apically. Median lobe with broad basal half, gradually narrowed apically. Basal strut very short ( Figs 50–51 ).

Material examined

CHINA: Guangdong: 1 ♂, 1 ♀, Danxiashan, 2 May. 2008, Fenglong Jia leg.; 2 ♂♂, 3 ♀♀, Danxiashan, 8 Jun. 2009, Fenglong Jia leg.; 1 spec., Shaoguan, Danxiashan, 27 May. 2010, Fenglong Jia leg.; 1 spec., Danxiashan, 21 Jul. 2011, Shuang Zhao leg.; 1 spec., Shaoguan, Danxiashan, 21 Apr. 2012, Haidong Chen leg.; 6 spec., Danxiashan, 23–26 Apr. 2013, Fenglong Jia, Shuang Zhao, Weicai Xie and Haidong Chen leg.; 3 spec., Danxiashan nursery, 8 Jun. 2012, light trap, Fenglong Jia leg.; 2 spec., Danxiashan, Yangyuanshan, 10 Apr. 2011, Fenglong Jia leg.; 1 spec., Zhuhai, campus of Sun Yat-sen University, 5–8 Jul. 2011, Fenglong Jia leg.; 1 spec., Fengkai, Heishiding, 3 Jun. 2011, light trap, Fenglong Jia leg.; 1 spec., Heshan, 22–24 Apr. 2002, Haidong Chen leg.; 1 spec., Heyuan, Wanlvhu, 15–17 Aug. 2005, Shuang Zhao leg.; 1 spec., Shenzhen, Longgang, 23–25 May 2011, Fenglong Jia leg.; 1 spec., Shenzhen, Neilingding, 4 Jul. 1998, Haidong Chen leg. – Hong Kong: 2 ♂♂, 3 ♀♀, 34 spec., Qingkuaitang, 29 Oct. 2013, light trap, Y.M. Lee, Eric Chen and Alex Lee leg.; 9 spec., Fengkeng, 22°31.695′ N, 114°13.450′ E, 13 m a.s.l., 9 Jun. 2014, Fenglong Jia, Weicai Xie and Huangjia Chen leg.; 7 spec., Dabujiao (Hexi), 22°25.697′ N, 114°10.834′ E, 144 m a.s.l., 10 Apr. 2014, Fenglong Jia, Weicai Xie and Huangjia Chen leg.; 2 spec., Rongshu’ao, 22°32.646′ N, 114°14.926′ E, 10 m a.s.l., 11 Apr. 2014, Fenglong Jia, Weicai Xie and Huangjia Chen leg. – Guangxi: 1 spec., Shiwandashan forest park, 263 m a.s.l., 7 Jul. 2011, light trap, Keqing Song leg. (English label); 2 spec., Shiwandashan forest park, 263 m a.s.l., 7 Jul. 2011, light trap, Keqing Song leg. (transcribed from Chinese); 1 spec., Shiwandashan, 8–12 Apr. 2013, Haidong Chen leg. (English labels). – Guizhou: 1 ♂, 1 ♀, Yaoshan, 25 May 1938. – Jiangxi: 1 ♂, Jiulianshan, Daqiutian, 31 Aug. 2007, light trap, Hong Pang leg. – Macao: 1 ♀, Ludang city, ecological reserve, section one, 9 May 2013, Weicai Xie leg. [All data transcribed from Chinese, unless otherwise specified.]

Redescription

FORM AND COLOUR. Body length 5.4–6.7 mm, width 3.2–3.7 mm, oval, moderately convex. Head uniformly black ( Figs 18, 21 ); pronotum dark brown to black, usually narrowly reddish brown laterally, posterior margins usually yellow brown laterally ( Figs 21, 23 ), elytra black, with reddish brown lateral margins ( Fig. 20 ); antennae, maxillary and labial palps uniformly reddish or yellowish brown ( Figs 18, 21 ). Ventral side dark brown to black, legs dark with reddish brown tarsomeres ( Figs 19, 24 ). Immatures with reddish brown pronotum and elytra and dark brown head.

HEAD. Labrum with fine and dense punctures, smooth between punctures, with distinct systematic punctures, anterior margin broadly emarginate. Clypeus broad, with coarser and sparser punctures than those on labrum, smooth between punctures, systematic punctures distinct; anterior margin clearly emarginate, at most slightly expanded in front of eyes, never impressed in front of eyes ( Figs 20–21 ). Eyes of moderate size, not emarginate anteriorly ( Figs 20–21 ), separated by ca 4.0× the width of one eye. Frons with as coarse and strong punctures as clypeus, with clear systematic punctures. Maxillary palps long and slender, ca 1.6× as wide as head, second and third palpomeres curved inwards, apical palpomere ca 0.85 × as long as penultimate, asymmetrical. Antennae with 9 antennomeres, scape ca 1.5× as long as pedicel, pedicel ca ¾ × as long as antennomeres 3–6 combined, club loosely segmented with dense pubescence. Mentum ca as wide as long, subquadrate, with strong v-shaped impression anteromedially, with coarse punctures, with wrinkles posteriorly ( Fig. 22 ). Submentum without a small glabrous area medially and with even, dense, coarse and strong punctures, smooth between punctures ( Fig. 22 ). Maxilla with a few punctures that are finer than those on submentum ( Fig. 22 ).

THORAX. Pronotum ca 2 × as wide as long, widest posteriorly, posterolateral margin broadly round, anterior and posterior margins smooth, with a very fine transverse groove, lateral margin with stronger groove; posterior margin slightly bisinuate, with median portion widely curved, punctures slightly coarser than those on head, with distinct setiferous systematic punctures ( Figs 20–21, 23 ). Prosternum bulging in middle, not carinate, pubescent, with transverse groove, protruding anteriorly ( Fig. 22 ). Mesoventrite with a stout, backwardly pointing projection, rising to level of mesocoxae, apex of projection with a few long setae ( Fig. 24 ). Metaventrite without glabrous area medially; metepisterna ca 3.5× as long as wide, subparallel. Scutellum triangular, with similar punctures to those on elytra. Ground punctures on elytra similar to those on pronotum and clearly with three distinct rows of systematic punctures ( Fig. 20 ); epipleura very broad anteriorly, reaching posterior margin of first visible abdominal sternite, with sparse, coarse punctures. Femora densely pubescent with apical eighth glabrous ( Figs 19, 25 ). Metatarsomeres with dense golden hairs ventrally and some long swimming hairs dorsally. Claws of moderate size, rather strongly curved.

ABDOMEN. All visible abdominal ventrites with dense pubescence; first ventrite not carinate ( Fig. 25 ).

AEDEAGUS. Very broad. Parameres somewhat wider than widest part of median lobe, each paramere with 3 branches: inner branch short and strongly curved inwards; median branch knife-formed, sharp apically, almost as long as outer branch; outer branch narrower than other two branches, apical third curved inwards, sharp apically. Median lobe with broad basal half, gradually narrowed apically. Basal strut very short ( Figs 50– 51 ).

Differential diagnosis

It is very easy to distinguish this species from other species known from China by its large size, dark brown to black colour, pronotum and elytra finely punctate, mesoventrite with a stout, backwardly pointing projection, rising to the level of the mesocoxae, the apex of the projection with a few long setae, each paramere with 3 branches. For the differences between H. atropiceus and allied species, see Hebauer (2001).

Biology

Living in natural ponds with leaf litter or water grass, can sometimes be collected on wet ground with plenty of grass. It can be collected at light in May and June in South China. It has never been collected from the edges of rivers and streams. The female carries the egg case under the abdominal ventrites.

Distribution

China (Guangdong, Guangxi, Guizhou, Hong Kong, Jiangxi, Macau), Bangladesh, Japan (Ryukyu Islands), Malaysia, Nepal, Thailand, Vietnam ( Fikáček et al. 2015; Hansen 1999). New record for Guizhou, Hong Kong and Macau.

Figures

Figs 18–25. Helochares atropiceus Régimbart, 1903. 18–20. Habitus. 18. Dorsal. 19. Ventral. 20. Lateral. 21. Head and pronotum. 22. Head and prosternum. 23. Pronotum, dorsolateral. 24. Mesoventrite. 25. 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).