Metrocoris dinendrai 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 : 265-267

Metrocoris dinendrai Basu, Polhemus and Subramanian , NEW SPECIES

Figs. 33–44

Material examined. Holotype: Apterous male: INDIA, West Bengal, Darjeeling District , roadside cascades within Neora Valley National Park , 27.0828°N, 88.7437°E, 2006m . asl, 3.X.2012, coll. S. Basu, deposited at the Zoological Survey of India, H.Q., Kolkata ( NZSI) Reg. No. 4774/H15.

Paratypes: INDIA, West Bengal: 1 apterous male, 1 apterous female, 31 nymphs: same data as holotype Reg. No. 4775/H15; 2 apterous males, 1 apterous female, 1 macropterous female, 5 nymphs, Darjeeling District, stream on the way to Chengey Falls, near Lava , 27.0511°N, 88.6800°E, 1639 m . asl, 3.X. 2012, coll. S. Basu ( NZSI) Reg. No. 4776/H15; 4 apterous males, 2 apterous females, 1 nymph, Darjeeling District, stream near Gorubathan , 26.96636°N, 88.7000°E, 370 m . asl., 1.X.2013, coll. S. Basu, (NZSI) Reg. No. 4777/H15.

Description. Apterous male (Holotype): Fig.33

Size: Body length 5.42 mm, maximum width across mesoacetabula 2.53 mm.

Colour: Dorsal body coloration yellowish to orange with dorsal black markings ( Fig. 33 ). Interocular dark mark rectangular, bifid posteriorly, anterior margin not connected with dark mark of postclypeus, posterior portion in some individuals connected with dark inner margin of eye. Antennal segments black, with first segment yellow basally. Eyes black. Dark marks on pronotum broad T-shaped, connected to propleural margin ( Fig.33 ). Meso- and metanota pale orange with dark markings as in Figs. 33 , sublateral dark stripes broader than yellowish part on apical half, longitudinal dark stripe of mesopleuron extending nearly through its length. Abdominal terga black except segment VIII. Thoracic venter black, with a deep yellowish patch laterally ( Fig. 36 ). Abdominal sterna II– VI black, sterna VII–VIII yellowish posteriorly. Fore femur black, basal one-fourth of ventral and dorsal surfaces yellowish, fore tibia and tarsus black. Rostrum black with pale yellowish lateral margins.

Structural characteristics: Head width 1.36, length 0.73. Interocular region wider than eye, widths 0.61 and 0.25 respectively. Eye length 0.62, posterior half of eye covering anterior one fourth of propleuron. Length of antennal segments I–IV: 2.29, 0.97, 0.88, 0.65, first segment longer than combined lengths of remainder. Rostrum length 1.46, surpassing fore trochanter. Pronotum slightly bulbous in male, wider than long, width 1.61, length 0.57, slightly wider than head. Meso- and metanota 1.12 times wider than combined length, width 2.55, length 2.27. Fore femur ( Fig. 39 ) slender and slightly curved at middle, ratio of length/width approximately 6.5, ventral surface with small constriction near middle, without indentation or tooth, with short dense hair fringe ventrally near apex, inner margin with rows of short hairs. Inner margin of fore tibia not modified, bearing rows of short hairs. Second tarsal segment long. Pretarsus with pair of sharp claws. Hind trochanter lacking modifications. Abdominal terga with prominent golden pubescence, combined length 1.83, maximum width 1.21. Abdominal sternum VIII bearing long dense hair fringe ( Fig. 37 ). For measurements of leg segments see Table 1 .

Male genitalia: Male abdominal sternum VIII ( Fig. 37 ) elongate, sub-oval, length 1.27, width 0.86, densely clothed with fringe of golden hairs. Posterior margin of abdominal tergum VIII straight. Pygophore ( Fig. 42 ) elongate, heavily setiferous, apex truncate. Proctiger ( Fig. 41 ) moderately elongate, lateral margins slightly convex, isolating angular basal lobes, apex broadly rounded, posterior margin with dense hair fringe. Parameres symmetrical ( Fig.43 ) strongly curved near midpoint, apical section expanded to small head with outer margin concave, apex blunt, inner and outer margins with long distinct setae, several whitish dots distributed throughout. Endosomal sclerites as in Fig. 44 .

Apterous female: Fig. 34

Size: Body length 4.41–4.55, maximum width across mesoacetabula 2.29–2.31.

Colour: Pattern of dark markings similar to that of male except much wider and more prominent; fore femur slender, lacking median invaginations; sterna VI–VII yellowish.

Structural characteristics: Head length 0.74, width 1.21. Length of antennal segments 1–4: 1.87, 0.65, 0.60, 0.72. Eye length 0.61, width 0.24, interocular width 0.66. Length of rostrum 1.45. Pronotum wider than long, length 0.50, width 1.54. Combined lengths of meso- and metanota 2.12, width 2.21. Fore femur length/width ratio 6.3, lacking medial constriction; fore pretarsi bearing sharp, curved claws; hind trochanter lacking modifications. Abdominal sterna II–VI combined length 0.96, maximum width 1.57. For measurements of leg segments see Table 2 .

Female terminalia: Abdominal sternum VII semi-circular, length 0.30, width 1.07, slightly constricted laterally, clothed with short golden pubescence.

Macropterous male: Unknown.

Macropterous female: Fig. 35

Size: Body length 5.32, maximum width across mesoacetabula 2.67.

Structural characteristics: Golden brown dorsally, marked with prominent black markings as shown in Fig.35 . Median length of pronotum 2.41, humeral width 1.72, length of lateral margin from anterior angle to humerus 0.89, length of lateral margin from humerus to apex 1.76, apex of pronotum pointed, medially slightly bulged.

Etymology. This name “dinendra” is a patronym dedicated to Professor Dinendra Roychoudhury of Department of Zoology of University of Calcutta, who had encouraged the first author to carry out entomological research.

Habitat. This species was collected from high mountainous cascades within the Neora Valley National Park of the Darjeeling District in West Bengal. The insects were found in steep, rocky areas flooded with splashing water, and appear adapted to the cold waters. A preference for rushing, high gradient upland streams has also been observed by the second author (DP) for another currently undescribed species of the Metrocoris compar species group collected in northern Vietnam, suggesting this habitat association may be typical of the group as a whole.

Comparative notes. Metrocoris dinendrai sp. nov. belongs to Metrocoris compar group based on the structure of male fore femur, which is slender and slightly curved; the strongly curved male parameres; the elongate male pygophore which bears dense dark pilosity; and the laterally constricted female terminal abdominal sterna. This new species can be recognized within this group by the distinctive shape of male paramere, which has a a slightly expanded apex that is somewhat concave on its outer margin ( Fig. 43 ); the structure of male endosomal sclerites ( Fig. 44 ); and the female trochanter clothed with thick black bristles. Within the Metrocoris compar group, M. dinendrai seems most similar to M. pardus from the Malay Peninsula ( Zettel, 2011a), but has the distal arm of the male paramere more slender and elongate, and the outer margin of the paramere apex concave rather than convex (compare Fig. 43 to Fig. 8 in Zettel, 2011a). The basal lobes on the male proctiger also are more angular than in M. pardus , whereas the internal sclerotization of the male endosoma is similar in both species.

Figures

FIGURES 33 – 44. Metrocoris dinendrai sp. nov. 33. Dorsal view of apterous male; 34. Dorsal view of apterous female; 35. Dorsal view of macropterous female; 36. Ventral view of apterous male; 37. Ventral view of male abdominal sternum; 38. Ventral view of female abdominal sternum; 39. Ventral view of male fore leg; 40. Genital capsule of male; 41. Male proctiger; 42. Male pygophore; 43. Male paramere; 44. Male endosomal sclerite.

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.