Metrocoris issaci, Jehamalar & Dash, 2021

Jehamalar, E. Eyarin & Dash, Swetapadma, 2021, Three new species of Metrocoris Mayr, 1865 (Heteroptera: Gerridae) from India and establishment of species groups, Zootaxa 5082 (4), pp. 341-356 : 346-347

Metrocoris issaci sp. nov.

( Figs. 2A–O )

Material examined: Holotype (apterous ♂): INDIA, MEGHALAYA, East Khasi Hills District, Sangmain, Umpaimmaw Nala , 1767 m a.s.l., 25.54208° N, 91.851° E, 8.iii.2016, Paratypes. 1 apt. ♂, 2 apt. ♀, 5 nymphs, same locality data as for holotype, Coll. E.E. Jehamalar.

Repository. The type specimens are deposited in the CEL, ZSI, New Alipore , Kolkata, West Bengal, India. Holotype Reg. No. 11559/H15 and paratypes Reg. No. 11560/H15.

Etymology. The new species is named after the first author’s second oldest brother Mr. E. Issac Vijaya Singh, for his constant support.

Diagnosis. The new species can easily be recognized by the presence of the long processes clothed with long setae on the coxa and the trochanter of the hind leg of the female; the hind coxal process of the female reaches half the length of the hind trochanter ( Figs. 2B, I ); the dorsosubapical region of the male paramere with a small excavation and dorsally with a V-shaped groove, the apical region ventrally with a nail-like pale mark ( Fig. 2N ).

Description. Apterous male (holotype): ( Figs. 2A, C–G, J–O ). Body length 5.67 (5.67–7.19, n=2), body width at mesoacetabula 2.64 (2.64–3.23, n=2).

Colour. Dorsum of body black with yellowish-brown marks; broad black mark on head slightly narrow anteriorly and broad posteriorly, posterosublaterally connected with black mark near eyes ( Figs. 2A, D ); median black mark on head slightly concaved posteriorly; antenna and legs dark-brown to black; antennal tubercle black; base of first antennal segment yellowish-brown ( Figs. 2A, D ); rostrum dark-brown to black, except lateral region of first to third segments yellowish-brown; proacetabulum black ( Figs. 2C, D ); pronotum with T-shaped black mark, sublateral mark broad curved downwards, extended laterally and connected to lateral mark of mesonotum ( Figs. 2A, D ), sublateral mark slightly concaved posteriorly ( Fig. 2A ); small area near anterolateral region of pronotum below eye yellowishbrown; fore femur dorsally and ventrally with broad black stripe connected to apical black ring, extensor region yellowish-brown ( Fig. 2A ); mesonotal longitudinal medial and lateral dark marks connected to horizontal black marks anteriorly and posteriorly, mesonotal black marks narrower than adjacent yellowish-brown marks; sublateral black mark of mesonotum not connected posteriorly to black mark between meso- and metanota, sublateral black mark basal half narrow and abruptly broad posteriorly; mesopleural black mark anteriorly connected with transverse black mark between propleura and mesopleura, posteriorly not connected with black mark of mesoacetabulum ( Fig. 2D ); mesopleural yellowish-brown mark broad and reaches up to sublateral region of mesosternum medially, apex extended anteriorly and posteriorly ( Fig. 2C ); yellowish-brown mark on metacetabulum uninterrupted ( Figs. 2A, J ); area above base of metacetabular region with small yellowish-brown mark; thoracic venter black, except mesosternal yellowish-brown mark on mediolateral region; coxa and trochanter of all legs yellowish-brown; mid femur dorsally with long thin brown stripe; dorsum of abdomen black, except connexival segments VI and VII, posteromedian region of terga V and VI and posterior half of tergum VII and lateral and posterior margins of tergum VIII yellowish-brown ( Fig. 2A ); venter of abdomen black, except from apical half of sternum VI to apex yellowishbrown, except sternum VII basally and medially and lateral region of pygophore dark-brown to black ( Fig. 2C ).

Structural characteristics. Body clothed with small black adpressed irregularly arranged setae; eyes covering anterior 1/3 of propleura ( Fig. 2D ); posterior margin of mesosternum covered with short silvery-white setae ( Fig. 2C ); sterna VI–VII clothed with long whitish-brown setae; antenna without any characteristic setae; head laterally with two to three long black setae in front of eyes; eye width greater than posterior eye width. Pleural region of prothorax posteriorly with few long black setae; anteromedian region of mesosternum with some long setae, prominent in lateral view; fore femur slender, basally with two long setae, almost medially with shallow notch; mid femur longer than hind femur; mesal region of meso- and metacetabula with thin stripe of short adpressed silvery-white setae to golden-yellow. Abdominal terga I–VII and connexivum clothed with short silvery-white to golden setae; sternum VII longer than combined length of sterna V and VI; posterior margin of sternum VII concave ( Fig. 2F ). Terminalia: Tergum VIII large, slightly wider than long, slightly concaved posteromedially, posteriorly and laterally fringed with long brown setae ( Fig. 2E ); basomedian region of sternum VIII smoothly raised and slightly depressed sublaterally ( Fig. 2F ); lateral margin of sternum VIII parallel-sided; sternum VIII distinctly longer than sternum VII; proctiger subovate ( Fig. 2L ), slightly visible from above ( Fig. 2E ); pygophore posteriorly convex with fringe of medium-sized setae, posterolaterally fringed with long setae ( Fig. 2M ); paramere falciform, dorsosubapical region with small excavation, nearly middle slightly raised with long and short setae, ventral region with nail-like pale mark at apex ( Fig. 2N ), visible from outside of genital segments laterally. Endosoma in lateral aspect: proximal region of dorsal sclerite inwardly curved, with short reflex angled process; dorsal sclerite concaved medially; accessory apical sclerite absent; accessory dorsal sclerite broad posteriorly and reached up to level of anterior region of lateral sclerite; anterior region of basal sclerite reached near middle of dorsal sclerite; lateral sclerite proximally slightly bend upwards, with blunt tip; ventral sclerite very long surpassing well beyond level of lateral sclerite in lateral view ( Fig. 2O ).

Measurements. Head length 0.94, width 1.54; eye length 0.64, width 0.39, posterior eye width 0.32; synthlipsis 0.67; lengths of antennomeres I–IV 2.35, 0.98, 1.01, 0.78. Pronotal length 0.60, width 1.62; combined length of meso- and metanota 1.92; mesosternal length 2.44; metasternal length 0.15. Lengths of leg segments: foreleg: femur 2.94, tibia 2.55, tarsomeres I–II 0.16, 0.86; mid leg: femur 7.86, tibia 5.61, tarsomeres I–II 2.87, 0.50; hind leg: femur 7.80, tibia 4.22, tarsomeres I–II 0.43, 0.53; widths of fore, mid, hind femora 0.46, 0.33, 0.22. Length of abdominal tergum 2.25; length of abdominal sternum 2.11; lengths of abdominal sterna II–VIII 0.12, 0.11, 0.10, 0.12, 0.13, 0.33, 0.55; proctiger length 0.03; pygophore length 0.59; combined length of abdominal sterna V–VI 0.24; length of abdominal tergum VIII 0.71, width 0.75.

Apterous female (paratypes): ( Figs. 2B, H, I ). Body length 5.65 (5.65–5.69, n=2), body width at mesoacetabula 3.11 (3.11–3.23, n=2).

Colour. Similar to apterous male, except for the following characteristics: dorsum of abdomen black, except tergum VII posteromedially with small yellowish-brown mark; abdominal sterna VI–VII brown.

Structural characteristics. Similar to apterous male, except for the following characteristics: hind coxa and trochanter with long processes clothed with long setae, coxal process longer than process of trochanter ( Figs. 2B, I ); flexor region of hind femur basally with setal fringe ( Fig. 2I ); genital segments completely concealed under sternum VII; sternum VII almost triangular, lateral constriction not prominent ( Fig. 2H ); abdomen short, not reaching apex of hind coxa ( Figs. 2B, I ).

Measurements. Head length 0.91, width 1.77; eye length 0.73, width 0.41, posterior eye width 0.40; synthlipsis 0.79; lengths of antennomeres I–IV 1.62, 0.90, 1.11, 0.90. Pronotal length 0.52, width 1.79; combined length of meso- and metanota 2.58; mesosternal length 2.94; metasternal length 0.16. Lengths of leg segments: foreleg: femur 2.78, tibia 2.39, tarsomeres I–II 0.16, 0.92; mid leg: femur 7.36, tibia 5.18, tarsomeres I–II 2.70, 0.50; hind leg: femur 7.10, tibia 3.96, tarsomeres I–II 0.43, 0.53; widths of fore, mid, hind femora 0.38, 0.31, 0.23; lateral length of hind coxal process 0.47; lateral length of hind trochanter process 0.26. Length of abdominal tergum 1.53; length of abdominal sternum 1.16; lengths of abdominal sterna II–VII 0.14, 0.11, 0.10, 0.13, 0.17, 0.50; combined length of abdominal sterna II–VI 0.65; combined length of abdominal sterna V–VI 0.30; length of tergum VII 0.17.

Distribution. Presently known only from East Khasi Hills, Meghalaya, India.

Comparative notes. Metrocoris issaci sp. nov. shares the characteristics like the presence of the setal fringe on the base of the flexor region of the hind femur of the female ( Fig. 2I ) and the falciform male paramere, having the convex area on the dorsal region near middle ( Fig. 2N ) and the reflex angled process on the proximal region of the dorsal sclerite and the long ventral sclerite surpassing the proximal region of the dorsal sclerite ( Fig. 2O ) with M. coxalis , M. nigriventris Tran & Polhemus, 2017 and M. josephi sp. nov. The new species differs from M. coxalis and M. nigriventris , by the presence of long processes on both the coxa and the trochanter of the hind leg of the female; in M. coxalis the process is present only on the hind coxa of the female and in M. nigriventris the hind coxal process is absent and the hind trochanter is slightly produced. Metrocoris issaci sp. nov. and M. josephi sp. nov. have processes on both the coxa and the trochanter of the hind leg of the female ( Figs. 2B, I ; 3C, J ); however, these processes are longer in M. issaci sp. nov. ( Fig. 2I ) when compared to M. josephi sp. nov. ( Fig. 3J ). Moreover, the area surrounding the omphalium is black in M. issaci sp. nov. ( Figs. 2C, H ) but it is yellow in M. josephi sp. nov. ( Figs. 3B, I ). The overall structure of the male paramere is almost similar in M. coxalis , M. issaci sp. nov., M. josephi sp. nov. and M. nigriventris ; however, there are distinct differences on the tip of the paramere in each species, in M. issaci sp. nov. it is subapically excavated both the dorsal and the ventral region ( Fig. 2N ), in M. josephi sp. nov. the excavation is present subapically only on the ventral region ( Fig. 3N ), in M. nigriventris it is subapically produced and in M. coxalis the paramere is apically bent outwards.

Figures

FIGURES 2. Metrocoris issaci sp. nov., apterous form: A, male, dorsal view; B, female, dorsal view; C, male, ventral view; D, male, lateral view; E, male, abdominal tip, dorsal view; F, male, abdominal tip, ventral view; G, male, abdomen, lateral view; H, female, abdomen, ventral view; I, female, abdominal tip showing coxa and trochanter of hind leg, dorsal view; J, male, abdomen, dorsal view; K, male, genital capsule, lateral view; L, male, proctiger, dorsal view; M, male, pygophore, dorsal view; N, male, paramere, lateral view; O, male, endosoma, lateral view.

FIGURES 3. Metrocoris josephi sp. nov.: A, macropterous male, dorsal view; B, same, ventral view; C, apterous female, dorsal view; D, apterous female, lateral view; E, macropterous membrane broken male (mac-da), lateral view; F, mac-da male, abdomen, dorsal view; G, mac-da male, abdominal tip, ventral view; H, same, lateral view; I, apterous female, abdomen, ventral view; J, apterous female, abdominal tip showing coxa and trochanter of hind leg, dorsal view; K, mac-da male, genital capsule, lateral view; L, mac-da male, proctiger, dorsal view; M, mac-da male, pygophore, dorsal view; N, mac-da male, paramere, lateral view; O, mac-da male, endosoma, lateral view.