Tenagogonus aruli, Jehamalar & Chandra, 2020

Jehamalar, E. Eyarin & Chandra, Kailash, 2020, A new species of Tenagogonus Stål (Hemiptera: Heteroptera: Gerridae) and first records of eight species of aquatic and semi-aquatic Heteroptera from India, Zootaxa 4718 (1), pp. 95-107 : 100-104

Tenagogonus aruli sp. nov.

( Figs. 2 A–I, 3A–I)

Material examined. Holotype (apterous ♂): INDIA, MEGHALAYA, South Garo Hills District, Gawbari Village, Dalwat Stream , 111 m a.s.l., 25.2031° N, 90.76053° E, 3.iii.2018 . Paratypes: 5 apt. ♂, 2 mac. ♂, 6 apt. ♀, 20 Nymphs, same data as for holotype . East Garo Hills District, 2 mac. ♂, Samanda R.F., Khera Village, Ningsik River , 280 m a.s.l., 25.56969° N, 90.56685° E, 19.vi.2016 . South West Khasi Hills District, 1 apt. ♀, 1 Nymph, Khapra Village, Stream , 404 m a.s.l., 25.23821° N, 91.24421° E, 9.iii.2018 . West Garo Hills District, 3 apt. ♂, 10 mac. ♂, 2 mac. ♀, 22 Nymphs, Gambegre Village, Skili Stream , 177 m a.s.l., 25.4343° N, 90.14153° E, 11.vi.2016 ; 4 apt. ♂, 1 mac. ♂, 4 Nymphs, Dadenggre, Tebongre Stream , 505 m a.s.l., 25.60968° N, 90.23759° E, 17.vi.2016 . All the specimens were collected by E. Eyarin Jehamalar.

Repository. The type specimens are deposited in the CEL, ZSI, New Alipore , Kolkata, West Bengal, India. Holotype Reg. No. 9365/H15 and paratypes Reg. No. 9366/H15 to 9370/H15.

Etymology. The new species is named after Mr. Arul G. Madhuram, Divisional Forest Officer, Khasi Hills Wildlife Division, Meghalaya, for his support.

Diagnosis. Tenagogonus aruli sp. nov. can be identified by the presence of an irregular longitudinal black stripe on the sublateral region of the abdominal sternum in the apterous form ( Figs. 2C, D ); the presence of a slight depression on the eighth abdominal sternum of the male ( Figs. 2C, H ; 3F ); the presence of a long connexival process in the female ( Figs. 2B ; 3A, B, D ); a medium sized spine-like connexival process in the male ( Figs. 2E, G, H ); the presence of a bead-like median longitudinal black mark on the abdominal dorsum ( Figs. 2A, B, E ); the dorsal endosomal sclerites apically with an excavation in lateral view ( Fig. 3I ), and the presence of two pairs of accessory lateral sclerites on the male endosoma ( Fig. 3I ).

Description. Apterous male (holotype): ( Figs. 2A , C–E, G–I; 3C, F–I). Body length 7.31 (6.29–7.31, n=5), body width at mesoacetabulum 2.17 (1.90–2.17, n=5).

Colour. Body yellowish brown; marks on dorsum of head, thorax and abdomen black; head with a small indistinct brown spot near anterior pair of trichobothria; eyes dark brown to black; head in front of eyes laterally with a black mark along antennal tubercle; omphalium of metasternum and surrounding area with orange hue.

Structural characters. Head: lateral marks on head reach to level of median pair of trichobothria, mesal pair of stripes anteriorly converge, not united and posteriorly united ( Fig. 2A ); eyes protruded lateral margin of pronotum; clypeal region of head produced ( Figs. 2A, C ); antenna slightly longer than body and slender, without any characteristic setae; rostrum not reaching middle of mesosternum ( Figs. 2C, D ). Thorax: black marks on pronotal lobe complete; pronotal lobe below humeral angle laterally with thin, short, sordid white stripe, not reaching apex; propleural region with single black stripe ( Fig. 2A ); proacetabular region posterodorsally with a black stripe and a faint brown hue laterally ( Fig. 2D ); mesopleural region with two black stripes united anteriorly; basal half of mesosternum with slight median longitudinal depression, sublateral region of mesosternum without any stripes ( Fig. 2D ); mesoacetabular region with two black longitudinal stripes, lateral stripe broader than mesal stripe ( Fig. 2E ); mesoacetabular suture with black stripe ( Fig. 2D ); metanotum medially with a longitudinal black stripe bifid posteriorly, posterior margin of metanotum with a wide W-shaped mark ( Fig. 2E ); area above metacetaubulum dorsally with medially interrupted longitudinal black stripe, metacetaubulum apically with a thin black stripe, laterally with a small brown to black hue ( Fig. 2E ); coxae of all legs apically with few short black setae; mid and hind coxae posteriorly with black hue; fore femur almost straight ( Fig. 2A ); femora of all legs with small spine like process; flexor region of hind femur with six widely spaced trichobothria; all legs apically with prominent claws. Abdomen: Terga I–VI medially with a black bead-like mark enclosed with yellow mark ( Figs. 2A, E ); tergum VII with caret-shaped black mark ( Fig. 2G ); venter of body with scattered short black adpressed setae; connexivum posteriorly well produced as medium sized spine-like process, straight, not surpassing abdominal apex, but surpassing abdominal segment VIII ( Figs. 2E , G–H); ventrolateral region of connexivum with black longitudinal stripe ( Fig. 2D ); sterna II–VII sublaterally with irregular brown to black stripe ( Fig. 2D ); mark on sternum VII posteriorly curved and united with connexival process ( Fig. 2H ); tergum VIII posteromedially with brown hue ( Fig. 2G ); sternum VIII medially with a wide longitudinal depression ( Figs. 2H , 3F ); proctiger pointed apically ( Fig. 3C ). Endosoma: lower apical region of dorsal sclerite with V-shaped excavation; lateral sclerite curved; accessory lateral sclerites two pairs, first pair of accessory lateral sclerite (asl-I) almost bone-shaped, second pair of accessory lateral sclerite (asl-II) rectangular ( Fig. 3I ); paramere small, triangular, clothed with short setae; pygophore as in Figs. 3G, H .

Measurements. Head length 1.08, width 1.43; eye length 0.59, width 0.31; synthlipsis 0.66; lengths of antennomeres I–IV 1.67, 1.34, 1.91, 2.69. Pronotal width 1.16; length of pronotal lobe 2.70, width 1.16; length of anterior part of pronotal lobe 0.69, posterior pronotal lobe length 2.08; metanotal length 0.56; prosternal length 0.53; mesosternal length 2.53; metasternal length 0.40. Lengths of leg segments: foreleg: femur 2.46, tibia 2.22, tarsomeres I–II 0.23, 0.31; mid leg: femur 5.69, tibia 4.35, tarsomeres I–II 1.92, 0.46; hind leg: femur 5.78, tibia 2.85, tarsomeres I–II 0.51, 0.31; widths of fore, mid, hind femora 0.21, 0.18, 0.14. Length of abdominal tergum 2.97; lengths of abdominal terga I–VIII 0.40, 0.34, 0.28, 0.28, 0.30, 0.32, 0.53, 0.26; widths of abdominal terga II–VIII (excluding connexivum) 0.70, 0.67, 0.69, 0.69, 0.67, 0.61, 0.48; maximum connexivum width at tergum IV 0.25; proctiger length 0.26; mesal length of connexival process 0.32; distance between connexival processes 0.47; lengths of sterna II–VIII 0.26, 0.27, 0.24, 0.24, 0.27, 0.33, 0.24; pygophore length 0.35. Combined length of abdominal sterna VI–VII 0.58.

Macropterous male (paratypes): ( Figs. 2F ; 3E ). Similar to apterous male except for the following characteristics: body length (including hemelytra) 7.54 (7.17–7.84, n=5), width at mesoacetabulum 2.04 (2.03–2.19, n=5); mesal mark on head slightly faded. Length of pronotal lobe 2.69, width 1.55; length of anterior pronotal lobe 0.55, length of posterior pronotal lobe 2.14; lateral stripe on pronotal lobe interrupted near humeral angle; pronotal lobe below anterior part with brown hue; pronotal lobe below humeral angle laterally with sordid white stripe, not reaching apex; mesopleural region with two black stripes, lateral stripe confined to subbasal region; brown mark on area above metacetabulum confined to posterior region; hemelytral length 4.72, width 1.14, hemelytra brown, veins dark brown ( Fig. 2F ), distance from abdominal tip to wing tip 0.41; irregular black mark on sublateral region of abdominal sternum absent; lengths of abdominal sterna VI–VIII 0.31, 0.35, 0.23; connexival spines long, surpassing abdominal apex ( Fig. 3E ), mesal length of connexival process 0.45, distance between connexival processes 0.70; distance between abdominal tip and connexival process tip 0.07.

Apterous female (paratypes): ( Figs. 2B ; 3A, B, D ). Body length 7.63 (7.46–8.01, n=5), body width at mesoacetabulum 2.60 (2.51–2.76, n=5).

Colour. Similar to apterous male except for the following characteristics: area above metacetabulum with uninterrupted black stripe; black mark on tergum I pruinose, open; median black mark on metanotum not bifid posteriorly and not reaching posterior margin.

Structural characters. Bead-like black mark on terga III–VII thin; abdominal tergum II shorter than tergum III; connexival process long, almost half of its length extended beyond abdominal apex; sublateral irregular mark on abdominal sternum broad, mark on sternum VII not moving towards connexival process; gonocoxae not fully concealed under sternum VII.

Measurements. Head length 1.13, width 1.40; eye length 0.58, width 0.34; synthlipsis 0.65; lengths of antennomeres I–IV 1.65, 1.24, 1.96, 2.36. Pronotal width 1.18; length of pronotal lobe 2.72, width 1.35; length of anterior part of pronotal lobe 0.59, posterior pronotal lobe length 2.13; metanotal length 0.62; prosternal length 0.44; mesosternal length 2.77; metasternal length 0.48. Lengths of leg segments: foreleg: femur 2.62, tibia 2.37, tarsomeres I–II 0.31, 0.36; mid leg: femur 6.09, tibia 5.38, tarsomeres I–II 2.12, 0.54; hind leg: femur 6.32, tibia 3.04, tarsomeres I–II 0.56, 0.42; widths of fore, mid, hind femora 0.22, 0.21, 0.15. Length of abdominal tergum 3.21; lengths of abdominal terga I–VIII 0.42, 0.32, 0.35, 0.34, 0.37, 0.40, 0.55, 0.15; widths of abdominal terga II–VII (excluding connexivum) 0.91, 0.81, 0.80, 0.78, 0.71, 0.56; maximum connexivum width at tergum V 0.38; proctiger length 0.31; mesal length of connexival process 0.92; distance between connexival processes 0.55; distance between abdominal apex and connexival tip 0.55; lengths of sterna II–VII 0.36, 0.39, 0.39, 0.41, 0.46, 0.60; gonocoxae length 0.18. Combined length of abdominal sterna VI–VII 1.07.

Macropterous female (paratypes): similar to apterous female and macropterous male except for the following characteristics: body length (including hemelytra) 7.75 (7.75–8.12, n=2), width at mesoacetabulum 2.04 (2.04–2.54, n=2); brown stripes on head faded. Length of pronotal lobe 2.79, width 1.64; length of anterior pronotal lobe 0.53, length of posterior pronotal lobe 2.24; hemelytral length 4.92, width 1.18, hemelytra brown, veins dark brown ( Fig. 2F ), distance from abdominal tip to wing tip 0.13; irregular black mark on sublateral region of abdominal sternum absent; lengths of abdominal sterna VI–VII 0.37, 0.49; connexival spines long, surpassing abdominal apex, mesal length of connexival process 0.77, distance between connexival processes 0.46; distance between abdominal tip and connexival process tip 0.49.

Distribution. Known only from Garo and Khasi Hills of Meghalaya, India ( Fig. 4C ).

Comparative notes. Tenagogonus aruli sp. nov. shares the character of having a median longitudinal depression or groove on the abdominal sternum VIII of male with T. bergrothi Hungerford & Matsuda, 1958 and T. curvatus Zettel, 2014 . In T. aruli sp. nov., sternum VIII of the male is medially longitudinally depressed and the groove is confined to the anterior region ( Fig. 3F ), whereas in T. bergrothi the sternum VIII has a narrow groove throughout its length, and in T. curvatus it is widened and deepened posteriorly. The connexival process of the male is lacking in both T. curvatus and T. bergrothi , but the connexival process is distinct and clearly surpass abdominal segment VIII but not reaching apex of proctiger in T. aruli sp. nov. Moreover, the fore femur is curved in T. curvatus , whereas in the new species it is straight. The connexival process of the female in T. bergrothi does not surpass the abdominal apex and in T. curvatus the seventh connexival segment is angularly produced and does not surpass the abdominal apex, whereas the connexival process in T. aruli sp. nov. extends well beyond the abdominal apex. The sublateral region of the abdominal sternum has an irregular black stripe in T. aruli sp. nov. but the stripe is absent in T. bergrothi and T. curvatus . The new species differs from T. kuiterti which also is distributed in Meghalaya, by having a very long connexival process in females. Tenagogonus aruli sp. nov. can readily be distinguished from T. ceylonensis , T. nicobarensis and T. venkataramani by the presence of connexival spines in male, whereas it is absent in these three species occur in India.

Figures

FIGURES 2A–I. Tenagogonus aruli sp. nov. apterous form unless otherwise mentioned: A, male, dorsal view; B, female, dorsal view; C, male, ventral view; D, male, lateral view; E, abdomen of male, dorsal view; F, macropterous male, dorsal view; G, abdominal tip of male, dorsal view; H, abdominal tip of male, ventral view; I, abdominal tip of male, lateral view.

FIGURES 3A–L. Apterous form of species of Tenagogonus unless otherwise mentioned: A–I, Tenagogonus aruli sp. nov.; A, abdominal tip of female, dorsal view; B, same, ventral view; C, proctiger of male, dorsal view; D, abdominal tip of female, lateral view; E, abdominal tip of macropterous male, ventral view; F, eighth abdominal segment of male, ventral view; G, genital capsule of male, lateral view; H, endosoma with pygophore, ventral view; I, endosoma, lateral view; J–L. Tenagogonus kuiterti: J, abdominal tip of male, ventral view; K, abdominal tip of female, dorsal view; L, abdominal tip of female, lateral view.

FIGURES 4A–C. A, Map of India showing location of state of Meghalaya; B, Distribution in Meghalaya of Ranatra libera in blue squares; Hydrometra jaczewskii in green triangles; H. longicapitis in red square; Gerris lobatus in pink circle; Rheumatogonus vietnamensis in black circle; C, Distribution in Meghalaya of Strongylovelia balteiformis in red circles; S. hainanensis in pink square; Tenagogonus aruli sp. nov. in green squares; T. kuiterti in blue circles.