Helotrephes nainamalaii, Jehamalar & Chandra & Zettel, 2018

Jehamalar, Eyarin, Chandra, Kailash & Zettel, Herbert, 2018, New species and first record of Helotrephes from India, and a check-list of Indian Helotrephidae (Hemiptera: Heteroptera), Acta Entomologica Musei Nationalis Pragae 58 (1), pp. 243-248 : 245-247

Helotrephes nainamalaii sp. nov.

( Figs 2A–I )

Type material. HOLOTYPE (brachypterous male): INDIA: MEGHALAYA: East Khasi Hills District, Janiaw Village, Phudjynniaw Stream , 1042 m a.s.l., 25.25731° N, 91.5745° E, 4.iii.2016, Coll. E. E. Jehamalar. PARA- TYPE: 1 brachypterous male, same collection data as for holotype. Both specimens are deposited in the Central Entomological Laboratory ( CEL), Zoological Survey of India ( ZSI), New Alipore, Kolkata, West Bengal, India: holotype Reg. No. 5887/H15, paratype Reg. No. 5888/H15.

Description of brachypterous male ( Figs 2A–I ). Size (holotype is a smaller specimen): Body length: 2.28 / 2.45. Maximum body width at posterolateral angle of cephalonotum: 1.71 / 1.81.

Colour. Dark brown to black. Anteromedian region of pronotum pale brown ( Fig. 2A ). Head yellowish brown with irregular black mark ( Fig. 2B ), near eyes yellowish. Legs yellowish brown.

Structural characters. Head: vertex near posterior margin of eye rugulose; anterior part without distinct punctures. Cephalonotal suture sinuate and distinct ( Fig. 2B ). Eye length 0.59, width 0.28. Fourth rostral segment almost 3.0 times as long as third. Pronotal plate with a very large, almost squared incision ( Fig. 2C ). Genal plate narrow, sub-basally with a small protrusion.

Punctures on entire dorsum bearing yellowish brown setae; pronotum with dense, small and shallow punctures; scutellum and hemelytra with sparse, large, deep punctures; corium sub-laterally reticulated. Mesoscutellum, length 1.09, basal width 0.94.

Ventral carinae ( Fig. 2D ): Prosternal carina deeply notched posteriorly, strongly protruding anterior corner and blunt posterior corner. Mesosternal carina anteriorly knob-like, posteriorly rounded. Metasternal carina almost squared, anteriorly elevated, posteriorly with blunt corner. Carina of sternum 2 large and almost sigmoid. Carina of sternum 3 with apical part almost reniform, with sparse long thin setae. Carinae of abdominal sterna 4 to 6 small and basally with thick setae.

Genitalia. Genital capsule as in Fig. 2E . Aedeagus ( Fig. 2G ) medium-sized, stout, with slightly convex posterior margin; apex of characteristic hook-like shape. Right paramere ( Fig. 2H ) slightly shorter than left paramere, slender and curved, posteriorly with 13 long setae evenly distributed in distal two thirds; apex round, but in a more posterior view ( Fig. 2F ) angularly produced. Left paramere ( Fig. 2I ) broad, abruptly narrowed distally, with blunt tip, with some setae posteriorly and on medial face.

Differential diagnosis. Helotrephes nainamalaii sp. nov. belongs to the H. australis group sensu ZETTEL & POLHEMUS (1998). It can easily be distinguished from all the other known species of the H. australis group by the presence of a sub-basal tubercle on the genal plate ( Fig. 2C ), by a strongly protruding anterior corner of the prosternal carina ( Fig. 2D ), and by the apical hook of the aedeagus basally bent backward and then forward ( Fig. 2G ). The first two characters should probably easily facilitate the recognition of the hitherto unknown female. Although the hook-shap- ed apex of the aedeagus resembles that of H. australis , a common and widespread species in Southeast Asia, H. nainamalaii differs from H. australis by the apical hook of the aedeagus being bent backward and then curved forward ( Fig. 2G ), while in H. australis it is simply curved forward ( Fig. 1B ). Moreover in H. australis the right paramere is very slender, and the left paramere has a curved apex ( Figs 1J–K ).

Etymology. Helotrephes nainamalaii is named after Mr. R. Nainamalai, Divisional Forest Officer, Jaintia Hills, Meghalaya, for arranging the field trip in the East Khasi Hills District.

Type locality and habitat ( Figs 3A–C ): Meghalaya is located between 25°01′N and 26°05′N latitude and 85°49′E and 92°52′E longitude. The East Khasi Hills district experiences an average annual rainfall of about 12,000 mm and is considered as one of the wettest regions on earth. About 39% of the district’s total area is forested (1067.52 km 2 out of 2748 km 2). The district is dissected by plenty of streams; the streams and rivers in the north flow toward the Brahmaputra River and those in the south toward the Surma River of Bangladesh. Phudjynniaw Stream located in East Khasi Hills District, is the tributary of Umngi River,

which flows into Bangladesh and meets with Surma River. It is a limestone-bedded slow flowing shallow stream with an open canopy ( Fig. 3C ).

Distribution. Known only from the type locality, Phudjynniaw Stream in Janiaw Village, Mawsynram Block, East Khasi Hills District, Meghalaya, India.

Figures

Figs 3A–C. Type locality of Helotrephes nainamalaii sp. nov. A – map of India; B – map of Meghalaya; triangle denotes the distribution of the new species; C – photograph of the type locality, Phudjynniaw Stream in Janiaw Village.

Fig. 2. Helotrephes nainamalaii sp. nov. (holotype, brachypterous male).A – habitus, dorsal view; B – head, frontal view; C – pronotal and genal plate, ventral view (arrows indicate incision of pronotal plate and sub-basal tubercle of genal plate); D – ventromedian carinae, lateral view (arrows indicate strongly protruded prosternal carina and blunt posterior corner of metasternal carina); E – genital capsule, lateral view; F – apex of right paramere, dorsolateral view; G – aedeagus, lateral view; H–, right paramere, lateral view; I – left paramere, lateral view.

Fig. 1. Key characters of species belonging to the Helotrephes australis species-group.A–E – aedeagi in right side view:A – H. recurvatus Zettel, 2000; B – H. australis Zettel & Polhemus, 1998; C – H. nieserianus Zettel & Polhemus, 1998; D – H. incisus Zettel & Polhemus, 1998; E – H. vietnamensis Zettel, 2005. F–I – pronotal and genal plate: F – H. recurvatus; G – H. globulus Zettel, 2004; H – H. australis; I – H. incisus. J – right paramere of H. australis. K – left paramere of H. australis. L–O – medioventral carinae: L – H. globulus; M – H. australis; N – H. recurvatus; O – H. incisus. Abbreviations: pr – prosternum; ms – mesosternum, mt – metasternum, 2–6 – carinae of abdominal sterna 2–6. Figures not on scale. Redrawn (with slight modifications) from ZETTEL & POLHEMUS (1998): B–D, H–K, M, O; ZETTEL (2000a): A, F, N; ZETTEL (2004a): G, L; and ZETTEL (2005): E.