Metrocoris murtiensis Basu, Polhemus and Subramanian

Basu, Srimoyee, Polhemus, D. A., Subramanian, K. A., Saha, G. K. & Venkatesan, T., 2016, Metrocoris Mayr (Insecta: Hemiptera: Gerridae) of India with descriptions of five new species, Zootaxa 4178 (2), pp. 257-277 : 258-261

Metrocoris murtiensis Basu, Polhemus and Subramanian , NEW SPECIES

Figs. 1–16

Material examined. Holotype: Apterous male: INDIA, West Bengal, Jalpaiguri District , Gorumara National Park , continuation of Murti River , small pool, 26.70178°N, 88.79384°E, 100 m . asl, 17.III.2012, coll. S. Basu, deposited in the Zoological Survey of India, H.Q., Kolkata ( NZSI) Reg. No. 4590/H15.

Paratypes: INDIA, West Bengal: 1 apterous male, 7 apterous females,7 nymphs: same data as holotype (in 70% alcohol, NZSI); 5 apterous males, 5 apterous females, 13 nymphs, Jalpaiguri District, forested pool infront of Chapramari Wildlife Sanctuary , 26.8724°N, 88.8735°E, 167 m. asl, 18.III.2012, coll. S. Basu ( NZSI) Reg. No. 4696/H15.

Description. Apterous male (Holotype): Fig. 1

Size: Body length: 4.91 mm; body width across acetabula 2.29 mm.

Colour: Dorsal body coloration yellowish to orange with dorsal black markings. Interocular dark mark on head arrow-shaped, bifid posteriorly, posterior margin connected with dark margin of eye on each side. Basal portions of antennal segments yellow. Rostrum yellow, narrowly dark brown at anterior and posterior ends. Dark mark on pronotum T-shaped with broad arms ( Fig. 4 ); broad arms of T-shaped mark with invagination. Meso- and metanota with dark markings prominent, black, typically as in Fig. 4 , lateral yellow portion with median black stripe extending half-length of body. Mid- and hind leg mostly black, yellow anteriorly. Fore femur yellowish with broad black stripe dorsally. Abdominal terga II–VIII blackish dorsally with median horizontal yellowish stripe on terga IV–VII. Tergum VIII yellowish with two black oval spots vertically separated by prominent median gap. Abdominal sterna yellowish.

Structural characteristics: Head width subequal to pronotum width. Head length 0.68, width 1.46. Eyes 2.3 times longer than broad, length 0.72, width 0.31. Interocular width 0.56. Posterior half of eyes covering propleura by 0.32. Length of antennal segments I, II, III, IV = 2.09, 0.80, 0.57, 0.49 respectively, second segment slightly longer than third. Rostrum reaching onto forecoxa, length 1.32. Pronotum bulbous, 2.6 times broader than long. Pronotum length 0.54, width 1.44. Meso- and metanota 1.2 times broader than long. Male fore femur ( Fig. 5, 6 ) strongly incrassate, stout, broad, with dorsally broad black median elongated marking, in some individuals the markings extending attaching to the rectangular markings distally, marked with subapical indentation, bearing a more or less sharp subapical tooth followed by a bidentate tooth near distal margin, visible in both dorsal and ventral view. Fore femur hairy near distal margin, ratio of length/width 3.5 (length/width: 2.05/0.58). Fore tibia modified, with a strong curvature basally, bearing a small pointed tooth near distal margin. Fore trochanter with three long setae. Fore, middle, and hind tibiae and tarsi with dark pilosity. Abdomen length including genital segment 1.91 mm (along midline). Genital segment 1.1 times longer than broad, covered with dense short hairs anteriorly and long hairs posteriorly. For measurements of leg segments see Table 1 .

Male genitalia: Segment VIII large and with dense pilosity, bearing two broad black semi-circular markings separated by distinct gap, almost covering genital segment ( Figs. 8, 9 ). Length of genital segment VIII 0.92. Pygophore prolonged, hairy. Proctiger ( Fig.14 ) prolonged, truncated distally. Parameres projecting slightly outward from abdominal segment VIII ventrally ( Fig. 12, 13 ). Paramere ( Fig. 16 ) large, stout, curved distinctly, with an almost acute apex and a small hook, twisted medially, then broadened and finally tapering slightly with uniform thickness towards the apex. Endosoma ( Fig. 15 ) with dorsal sclerite long, expanded horizontally, almost covering the endosomal sheath and recurved proximally; lateral sclerite apically bent, almost straight, ventral sclerite long, extending beyond the dorsal sclerite, concave sub-medially.

Apterous female: Fig. 2

Size: Body length 4.10 mm; body width across acetabula 2.18 mm.

Species Fore leg Mid leg Hind leg

MALES Fem Tib Tar1 Tar2 Fem Tib Tar1 Tar2 Fem Tib Tar1 Tar2 Colour: Color pattern and markings similar to male.

Structural characteristics: Head length 0.50, width 1.29. Length of antennal segments I, II, III, IV = 0.39, 0.74, 0.54, 0.43. Interocular width 0.56. Eye length 0.62, width 0.35. Length of rostrum 1.02. Pronotum 3.3 times broader than long. Length of whole abdomen 1.32. Fore femur slender, elongated, with two long setae. For measurements of leg segments see Table 2 .

Female terminalia: Abdominal sternum VII ( Fig. 11 ) length 0.66, width 0.63, moderately large, broad and triangular with reflexed rectangular median lobe entirely covering rounded genital segments ( Fig. 10 ), laterally convex, hairy dorsally ( Fig. 10 ).

Macropterous forms. Unknown

Etymology. The specific epithet murtiensis is derived from the Murti River type locality.

Habitat. This species was collected from a stagnant pool adjacent to the rain-fed Murti River, a tributary of the Teesta River that traverses the Darjeeling and Jalpaiguri districts. It is common in small pools or stagnant water bodies along a continuation of the Murti River within the core forest area of the Gorumara National Park in the Jalpaiguri District, lying in the sub-Himalayan region of West Bengal. The bottoms of the pools where this species occurred consisted of gravel and boulders, but with little fine sediment or mud.

Comparative notes. Metrocoris murtiensis Basu, Polhemus and Subramanian sp. nov. is a member of Metrocoris nigrofasciatus group and is closely related to M. borneensis D. Polhemus on the basis of the structure of the male fore femur, which in the latter species bears a small, acute tooth proximal to the sub-apical concavity, and a larger, roughly trapezoidal tooth distal to this cavity, rather than a squared off tooth as seen in M. murtiensis . The paramere also is similar to that of M. borneensis , but more elongate and with the curvature more gradual and less even; the apex also possesses a small acute hook, which is lacking in M. borneensis .

Figures

FIGURES 1 – 7. Metrocoris murtiensis sp. nov. 1. Dorsal view of apterous male. 2. Dorsal view of apterous female. 3. Ventral view of apterous male. 4. Head and nota of male. 5. Dorsal view of male fore leg. 6. Ventral view of male fore femur. 7. Ventral view of female fore leg.

FIGURES 8 – 16. Metrocoris murtiensis sp. nov. 8. Dorsal view of male abdomen. 9. Ventral view of male abdomen. 10. Dorsal view of female abdomen. 11. Ventral view of female abdomen. 12. Dissected male genital capsule with segment VIII. 13. Lateral view of male genital capsule including pygophore and paramere. 14. Male proctiger. 15. Male endosomal sclerite. 16. Male paramere.

Tables

TABLE 1. Measurements of leg segments of male Metrocoris spp. (in mm).

M. murtiensis 2.04 1.80 0.13 0.52	5.72 3.73 0.43 0.63	5.16 2.07 0.34 0.52
M. lavitra 2.68 2.56 0.14 1.10	10.08 6.13 0.86 0.54	8.06 4.32 0.94 0.44
M. dinendrai 2.47 2.11 0.19 0.74	6.61 4.95 2.34 0.40	6.94 3.87 0.36 0.46
M. deceptor 2.68 2.27 0.21 0.71	6.82 5.01 2.43 0.52	6.77 4.43 0.39 0.47
M. darjeelingensis 2.31 2.1 0.21 0.68	5.99 4.05 1.87 0.40	5.51 3.21 0.26 0.44

TABLE 2. Measurements of leg segments of female Metrocoris spp. (in mm).

Species FEMALES	Fore leg Fem Tib Tar1 Tar2	Mid leg Fem Tib Tar1 Tar2	Hind leg Fem Tib Tar1 Tar2
M. murtiensis	1.31 1.45 0.13 0.54	4.23 2.89 0.31 1.49	4.30 2.27 1.83 1.01
M. lavitra	2.94 2.67 0.17 1.14	9.75 6.01 0.75 0.48	7.61 5.64 1.34 0.79
M. dinendrai	2.41 2.02 0.13 0.76	6.9 4.82 2.15 0.45	6.88 3.93 0.36 0.46
M. deceptor	2.10 1.57 0.12 0.66	6.56 4.79 2.32 0.48	6.52 4.36 0.35 0.42
M. darjeelingensis	2.17 2.11 0.13 0.71	5.85 4.01 1.79 0.38	5.48 3.19 0.24 0.41