Amemboa mahananda, Basu, Srimoyee, Subramanian, K. A. & Polhemus, An. A., 2014

Basu, Srimoyee, Subramanian, K. A. & Polhemus, An. A., 2014, Two new species of Amemboa Esaki (Heteroptera: Gerridae) from West Bengal, India, Zootaxa 3774 (6), pp. 567-577 : 568-571

Amemboa mahananda sp. nov.

( Figs. 1–15 )

Type Material: Holotype: Apterous male, INDIA: West Bengal, Darjeeling District, Mahananda Wildlife Sanctuary, stagnant pool, Lat. 26.828844°N, Long. 88.413944°E, alt. 180 m, 20.iii.2012, coll. Srimoyee Basu; Reg. No. 3095/H15.

Paratypes. INDIA: West Bengal: 8 apterous males, 3 apterous females, same data as holotype; Reg. No. 3096/ H15; 4 apterous males, 1 macropterous male, 3 apterous females, 2 immatures, Darjeeling District; Mahananda Wildlife Sanctuary, Panchanoi River, Lat. 26.827961°N; Long. 88.423169°E, alt. 170 m, 20.iii.2012, coll. Srimoyee Basu; Reg. No. 3097/H15.

Description: Apterous male ( Fig. 1 ). Size: (Measurement of Holotype in paranthesis) Body length 3.24–3.48 mm (3.36 mm); maximum width across mesoacetabula 1.10–1.20 mm (1.13 mm).

Colour: Black with prominent yellowish orange markings and silvery dots dorsally. Head yellowish with a roughly ‘V’ shaped black mark medially, a pair of black elongated spots near the inner margin of eyes. First antennomere yellowish; 2nd, 3rd and 4th antennomeres brownish in colour. Rostrum yellowish with a median brown stripe. Pronotum with a roughly ‘W’ shaped yellow mark, laterally connected to the propleural stripes. Mesonotum and metanotum also with a prominent broad ‘W’ shaped yellow mark. Certain individuals with middle arm of this ‘W’ disconnected from remainder of the two arms. Metapleura with yellow stripes, broader than the black portion. Abdominal tergites black with square-shaped yellowish markings medially. Genital segments (tergite VIII) black with three triangular, small yellowish markings anteriorly. Ventral surface with prosternum, meso- and metasternum ochraceous, with a light median black stripe projecting anteriorly along about two-thirds of metasternum; Abdominal sternites including genital segment yellowish with a pale brown ‘V’ shaped marking ( Fig. 7 ).

Structural characteristics: Antennal segments spiny; 1st, 2nd, and 3rd antennomere almost equal in length; length of antennomeres 1–4: 0.78; 0.74; 0.75; 0.86 mm respectively. Rostrum 1.40 mm in length, surpassing the fore trochanter. Fourth antennomere 1.6 times longer than head (head length 0.53 mm); head little broader than long. Interocular region 2.4 times longer than eye width (interocular width/ eye width =0.44/0.18). Pronotum wider than head, 2.1 times broader than long (width/length =0.89/ 0.41mm). Mesonotum and metanotum (length 1.20 mm) 2.9 times longer than pronotum. Posterior eye width (0.14 mm) almost equal to eye width. Fore femur with three hairy black patches located almost equidistantly, followed by a shallow curvature distally. In some specimens, the last two black hairy patches connected with a median hairy zone distally as in Fig. 4 , where as some lack this continuation. Middle femur 2.5 times as long as fore femur and 1.1 times longer than hind femur. Fore tibia hairy, basally with an indentation. Tarsus with a pair of prominent curved claws. Measurements of different leg segments are provided in Table 2 .

Male genital segment: Abdomen including genital segment 1.3 times longer than the width (length/width =0.91/0.72). Sternite VIII 1.3 times longer than width (length/width = 0.96/0.7). Genital segment almost rectangular with its curved lateral arm of proctiger projecting outward in some individuals, however, in others, this is hidden within the genital segment. Pygophore and proctiger as in Figs. 15 & 12 . Pygophore widened basally on ventral view, but tapering distally, with scattered long hairs medially and densely arranged hairs along its margin. Proctiger shaped as roughly arrow-shaped, outer margin curving inward. The lateral arms of proctiger long, slender curved at middle, distally almost straight, weakly narrowed towards truncated apex ( Figs. 13 & 14 ).

Apterous female ( Fig. 2 ). Size: Body length 3.42–3.69 mm; maximum width across mesoacetabula 1.30–1.36 mm.

Colour: Similar as in apterous male, except, with a broad prominent black stripe projecting from anterior margin of mesosternum to last abdominal segment, followed by a pair (1+1) of half bracket shaped black markings on each side.

Structural characteristics: Similar to apterous male. Fore leg relatively simple, without any markings ( Fig.5 ). Mid femur 3.1 times longer than the fore femur; eye 1.7 times as long as broad (length/width = 0.32/ 0.18mm). Rostrum length 1.17 mm. Head 1.3 times longer than interocular width. Head as long as width (0.60 mm). Pronotum 1.9 times broader than long (width/length =0.87/ 0.45 mm). Abdomen relatively short, sternite VII almost in equal length of sternite II–VI combined, with little pilosity at rear margin. Genital segment bucket shaped, much wider anteriorly ( Figs. 8 & 9 ). Measurements of legs as in Table 3 .

Macropterous male ( Fig. 3 ). Size: Body length exclusive of wings 3.44 mm, inclusive of wings 4.56 mm; maximum width across mesoacetabula 1.15 mm. Humeral width 1.19 mm; length of wing 2.28 mm.

Colour and structural characteristics: Similar to those of apterous male except, wings grayish with prominent venation. Median length of pronotum 1.14 mm. Pronotal lobe blackish brown. Pronotum of macropterous male with two yellow median stripes. Length of lateral margin from anterior angle to humerus 0.77 mm. Length of lateral margin from humerus to apex 0.94 mm. Measurements of leg segments as in Table 4 .

Macropterous female: Unknown

Etymology. Amemboa mahananda sp. nov. was collected from a shady stagnant pool in the Mahananda Wildlife Sanctuary of the Darjeeling District, West Bengal. The specific epithet ‘ mahananda ’ is derived from the name of the protected area which is the type locality of this newly described species.

Habitat. The type series of specimens was collected from a shaded, stagnant pool covered with algae, created by the Panchanoi River within the forest, and also from the banks of the slow-flowing, shady Panchanoi River. This species was found in good numbers near the steep, shaded banks of the stream.

Comparative notes. Amemboa mahananda sp. nov. is a close relative of Amemboa speciosa Polhemus & Andersen, 1984 from southern Vietnam. However, we have examined the paratype series of the latter species, held in the collection of the Bishop Museum, and find that the two species exhibit the following differences: 1) the males of both species possess three black hairy patches on the fore femur, but in A. speciosa the middle patch is more elongate and tapering, and is separated from the more distal patch by a gap that is two times greater than the distance to the basal patch, rather than being equidistant between the basal and distal patches as seen in A. mahananda ( Fig. 4 ); 2) in Amemboa mahananda sp. nov. the pygophore when viewed laterally is slightly curved upward towards its distal end and apically pointed, while in Amemboa speciosa Polhemus & Andersen the pygophore lies in a horizontal orientation, and is rounded apically (compare Fig. 15 to Fig. 86 in J. Polhemus & Andersen 1984); 3) the male lateral arms of proctiger of A. mahananda are distally curved ( Figs. 13, 14 ), and in ventral view fold under the subapical portion of the pygophore ( Fig. 8 ), whereas in A. speciosa the lateral arms of proctiger are distally straight in both lateral and ventral views, with their distal sections lying parallel to the pygophore and not folding underneath it, and their apices more acuminate (compare Fig. 12 to Fig. 86 in J. Polhemus & Andersen 1984); and 4) in A. mahananda sp. nov. the proctiger of the male is arrow-shaped and bears long setae medially, while in A. speciosa the proctiger possesses only a few setae on its outer margin. This character state combination involving the form of the male genitalic structures, the fore leg structure (specifically the form of the three hair tufts on male fore femur), and the pattern of markings on the pro-, meso- and metanota of both sexes serves to distinguish this species from others in the genus Amemboa .

Figures

FIGURES 1 – 4. Amemboa mahananda sp. nov., (1) Dorsal view of apterous male; (2) Dorsal view of apterous female; (3) Dorsal view of macropterous male; (4) Fore leg of male, dorsal view.

FIGURES 5 – 10. Amemboa mahananda sp. nov., (5) Fore leg of female, dorsal view; (6) Male genital segment, dorsal view; (7) Male genital segment, ventral view; (8) Female abdominal tergites, dorsal view; (9) Female abdominal tergites, ventral view; (10) Lateral view showing pleural marking pattern.

FIGURES 11 – 15. Amemboa mahananda sp. nov., (11) Dorsal view of dissected genital segment; (12) Pygophore and proctiger, lateral view; (13 – 14) Male lateral arms of proctiger (two opposite views); (15) Ventral view of Pygophore.

Tables

TABLE 2. Measurements (in mm) of leg segments of males (n = 13) of Amemboa mahananda sp. nov.

Leg	Femur	Tibia	Tarsus1	Tarsus2
Fore leg	1.10–1.14	0.95–0.98	0.13–0.16	0.30–0.33
Mid leg	2.84–2.88	1.93–1.99	0.73–0.75	0.34–0.37
Hind leg	2.56–2.58	1.09–2.10	0.45–0.46	0.38–0.41

TABLE 3. Measurements (in mm) of leg segments of females (n = 6) of Amemboa mahananda sp. nov.

Leg	Femur	Tibia	Tarsus1	Tarsus2
Fore leg	0.82–0.85	1.04–1.10	0.13–0.16	0.30–0.31
Mid leg	2.64–2.68	1.91–1.93	0.65–0.67	0.32–0.34
Hind leg	2.51–2.53	1.12–1.15	0.46–0.48	0.29–0.31

TABLE 4. Measurements (value in mm) of leg segments of macropterous male (n = 1) of Amemboa mahananda sp. nov.

Leg	Femur	Tibia	Tarsus1	Tarsus2
Fore leg	1.17	0.99	0.16	0.33
Mid leg	2.91	2.10	0.79	0.39
Hind leg	2.64	1.15	0.48	0.40