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

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Metrocoris murtiensis Basu, Polhemus and Subramanian


Metrocoris murtiensis Basu, Polhemus and Subramanian  , NEW SPECIES

Figs. 1–16View FIGURES 1 – 7View FIGURES 8 – 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 mGoogleMaps  . asl, 17.III.2012, coll. S. Basu, deposited in the Zoological Survey of India, H.Q., Kolkata ( NZSIAbout NZSI) Reg. No. 4590/H15. 

Paratypes: INDIA, West Bengal: 1 apterous male, 7 apterous females,7 nymphs: same data as holotype (in 70% alcohol, NZSIAbout 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 ( NZSIAbout NZSI) Reg. No. 4696/H15.GoogleMaps 

Description. Apterous male (Holotype): Fig. 1View FIGURES 1 – 7

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. 4View FIGURES 1 – 7); broad arms of T-shaped mark with invagination. Meso- and metanota with dark markings prominent, black, typically as in Fig. 4View FIGURES 1 – 7, 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, 6View FIGURES 1 – 7) 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, 9View FIGURES 8 – 16). Length of genital segment VIII 0.92. Pygophore prolonged, hairy. Proctiger ( Fig.14View FIGURES 8 – 16) prolonged, truncated distally. Parameres projecting slightly outward from abdominal segment VIII ventrally ( Fig. 12, 13View FIGURES 8 – 16). Paramere ( Fig. 16View FIGURES 8 – 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. 15View FIGURES 8 – 16) 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. 2View FIGURES 1 – 7

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. 11View FIGURES 8 – 16) length 0.66, width 0.63, moderately large, broad and triangular with reflexed rectangular median lobe entirely covering rounded genital segments ( Fig. 10View FIGURES 8 – 16), laterally convex, hairy dorsally ( Fig. 10View FIGURES 8 – 16).

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  .

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

Zoological Survey of India, National Zoological Collection