Metrocoris darjeelingensis 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 : 269-273

Metrocoris darjeelingensis Basu, Polhemus and Subramanian , NEW SPECIES

( Figs. 56–67 )

Material examined. Holotype: Apterous male: INDIA, West Bengal, Darjeeling District , cascades within Neora Valley National Park , 27.0960°N, 88.6098°E, 3.X.2012, coll. S. Basu, deposited at NZC, Zoological Survey of India, H.Q., Kolkata ( NZSI) Reg. No. 4652/H15.

TABLE ³ . Morphological characteristics of males of species of Metrocoris occurring in Inđia.

No. Species (Male) Body Length Interocular Marking Pronotum Fore femora Genital segment (mm.) (Abdominal segment VII)

Metrocoris murtiensis sp. nov. 4.9 Arrow heađ shapeđ, bifiđ Bulbous Strongly incrassate, with inđentation Long posteriorly anđ a bi-đentate, square shapeđ

tooth

. Metrocoris malabaricus 5.7 Rectangular, shallowly Not bulbous Slenđer, without inđentation, More or less semi- Thirumalai, 1986 bifiđ anteriorly anđ unarmeđ circular posteriorly

. Metrocoris variegans 5.5 Rectangular,shallowly Not bulbous Slenđer, without inđentation, More or less semi- Thirumalai, 1986 bifiđ anteriorly, not unarmeđ circular đistinctly bifiđ posteriorly

……continued on the next page Paratypes: INDIA, West Bengal: 2 apterous males, 1 apterous female, 14 nymphs: same data as holotype (in 70% alcohol); 2 apterous males, 8 apterous females , INDIA, Sikkim, East Sikkim District, Mandakini waterfalls, 26.III.2014, coll. S. Basu (in 70% alcohol, NZSI) .

Description. Apterous male (Holotype): Fig. 56

Size: Body length: 5.04 mm; body width across mesoacetabula 2.43 mm.

Colour: Dorsal body coloration yellowish to orange with distinct black markings. Interocular dark mark on head rectangular, bifid posteriorly, posterior margin connected with dark margin of eye on each side. Basal portions of antennal segments yellow. Rostrum black. Dark mark on pronotum T-shaped with broad arms ( Fig. 56 ). Meso- and metanota with prominent black markings typically as in Fig. 56 , lateral yellow portion with median black stripe extending full-length of body. Fore femur mostly black, but yellowish basally. Mid femur yellow with black stripe laterally, mid tibiae and tarsi and hind leg black. Ventrally black with distinct yellow markings on mesothorax. Abdominal terga II–VII blackish dorsally. Abdominal sterna II–VII black and VIII sternum yellow.

Structural characteristics: Head length 0.64, width 1.46, which is subequal to pronotum width. Eyes 2.5 times longer than broad, length 0.53, width 0.21. Interocular width 0.67. Length of antennal segments I, II, III, IV = 2.00, 0.77, 0.73, 0.61 respectively, third segment equal to the fourth segment. Rostrum reaching beyond forecoxa, length 1.61. Pronotum slightly bulbous, 2.8 times broader than long. Pronotum length 0.51, width 1.45. Meso- and metanota 1.71 in length and 2.13 in width. Male fore femur ( Fig. 59 ) slender and hairy, dorsally black and ventrally with black median elongated marking, basally yellow, without any modification, but with a slight invagination near middle, ratio of length/width 6.4 (length/width: 2.32/0.34), density of hairs increase apically. Fore tibia without any modification. Mid coxa with few setae. Abdomen length including genital segments 1.82 (along midline), width 0.94 mm. Genital segment 1.16 times longer than broad, covered with dense short hairs, the density of which increases posteriorly. For measurements of leg segments see Table 1 .

Male genitalia: Segment VIII elongated and with dense pilosity, lateral margins with few long setae ( Fig. 61 ). Length of genital segment (VIII) 0.84 and width 0.72. Pygophore ( Fig. 64 ) prolonged, broad and setiferous. Proctiger ( Fig. 65 ) prolonged, truncated distally, with distinct dark long setae throughout. Parameres ( Fig. 67 ) not visible externally, large, stout, curved distinctly in the middle, twisted medially, then broadened and finally tapering slightly towards the truncated apex and the posterior end, with 2–3 setae near middle and several white dots distributed up to apex. Endosoma ( Fig. 66 ) poorly sclerotised, with dorsal sclerite long, expanded horizontally and recurved proximally; lateral sclerite apically reflexed, almost straight, ventral sclerite long, not extending beyond the dorsal sclerite, concave sub-medially.

Apterous female: Fig. 58

Size: Body length 4.54 mm; body width across acetabula 2.49 mm.

Colour: Color pattern and markings similar to male.

Structural characteristics: Head length 0.73 width 1.34. Length of antennal segments I, II, III, IV = 1.84, 0.64, 0.84, 0.67. Interocular width 0.75. Eye length 0.54, width 0.27. Length of rostrum 1.59. Pronotum 0.47 in length and 1.48 in width. Length of abdomen 1.30, width 1.53. Fore femur slender, elongated, without any modification. Hind coxa with few long setae; hind trochanter with a pointed apex bearing a distinct, tapering tuft of long hairs ( Fig. 60 ). For measurements of leg segments see Table 2 .

Female terminalia: Abdominal sternum VII ( Fig. 62 ) length 0.61, width 0.79, small, broad and rectangular, hairy, laterally little constricted and with a smooth caudal margin entirely covering rounded genital segments ( Fig. 10 ), laterally convex, hairy dorsally ( Fig. 62 ).

Macropterous forms. Unknown

Etymology. The specific epithet darjeelingensis is derived from the District of Darjeeling from where it was collected.

Habitat. This species was collected from a cascade flowing within the Neora Valley National Park of Darjeeling district. It was also found abundantly in the waterfalls of Sikkim. This species occurs in the turbulent water of mountain streams in both Sikkim and the Darjeeling Himalaya.

Comparative notes. Metrocoris darjeelingensis Basu, Polhemus and Subramanian sp. nov. is a member of Metrocoris compar group and is closely related to Metrocoris coxalis Chen & Nieser (1993a) on the basis of the male paramere, which extends beyond the genital segment, has a more expanded and truncate apex, and possesses setae in the twisted middle region ( Fig. 67 ); and by the male fore femur, which has a small but distinct concavity centrally on the ventral margin ( Fig. 59 ). In addition, the female of M. coxalis Chen and Nieser possesses distinctive projections on the hind coxae, which are lacking in M. darjeelingensis , the latter instead possessing distinctive setiferous projections on the hind trochanter ( Fig. 60 ). Chen & Nieser (1993b) state that the ventral coloration in M. coxalis is yellowish with a broad median dark mark between the mesocoxa, and that the male metasternum is pale, whereas in M. darjeelingensis sp. nov. the venter is almost entirely black ( Fig. 57 ) with only limited yellowish markings laterally. Collection of additional material of M. coxalis Chen and Nieser will be required to permit a more detailed comparison with our new Indian species, and may reveal additional differences between them.

Figures

FIGURES 56 – 67. Metrocoris darjeelingensis sp. nov. 56. Dorsal view of apterous male; 57. Ventral view of apterous male; 58. Dorsal view of apterous female; 59. Ventral view of male fore femur; 60. Female hind coxa and trochanter; 61. Male sternum including genital segment; 62. Female abdominal sternum; 63. Dissected pygophore and proctiger with paramere; 64. Pygophore (dorsal view) of male; 65. Proctiger (dorsal view) of male; 66. Male endosoma showing sclerites; 67. Male paramere.

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.