Halictophagus prominens, Roy, Sukhendu & Hazra, Niladri, 2016

Roy, Sukhendu & Hazra, Niladri, 2016, Two new species of Halictophagidae (Insecta: Strepsiptera) including the first record of genus Coriophagus Kinzelbach from India, Zootaxa 4189 (1), pp. 581-587 : 585

Halictophagus prominens n. sp.

LSIDurn:lsid:zoobank.org:act:7B44ADCB-1C4D-4 A 54-8135-013F0882EE96 ( Figs. 11–19 )

Material examined. Holotype male (Type No. BU Ent. 287), India, West Bengal, Illambazar (23°63'N, 87°53'E), 05.iv.2016, open light trap, Coll. Sk. Basir.

Etymology. The name “ prominens ”, is coined from the Latin meaning of projection of tergite X beyond the base of aedeagus.

Male adult (n = 1). Total length 2.36 mm; length of the metathorax 0.88 mm; width of metathorax 0.38 mm; length of the antenna 0.42 mm.

Colour. Head and thorax deep brown, abdomen light brown, hind wing smoky.

Head. Head transversely elongated, scape of antenna slightly protruded anteriorly, posterior margin of head concave. Head length 0.11 mm, width 0.41 mm. Eyes prominent, consisting of 15–18 ommatidia when viewed dorsally. Antenna seven segmented ( Fig. 11 ), antennomeres I 0.06 mm long, II 0.04 mm long, bases of III–VI extended laterally into stout flabella, III with flabellum longest, 0.31 mm long and 0.05 mm wide, IV with flabellum broadest, 0.28 mm long and 0.07 mm wide, antennomeres V and VI with flabellum 0.19 mm long each, antennomere VII 0.22 mm long. Maxillary palp almost double in length in comparison to the maxillary base ( Fig. 12 ). Maxilla with 0.05 mm long base and 0.12 mm long palp. Mandible ( Fig. 13 ) 0.044 mm long, short, cone-shaped and sclerotized.

Metathorax ( Fig. 14 ). Prescutum broadly rounded anteriorly, moderately protruded from scutum, prescutum 0.18 mm long and 0.15 mm in width; scutellum roughly subpentagonal shaped, slightly extended caudolaterally; postlumbium broad, slightly constricted in centre by inward curvature of both anterior and posterior margins, postlumbium length 0.28 mm and width 0.05 mm; postnotum 1.5 times longer than wide (0.35 mm long and 0.23 mm width), and broadly rounded posteriorly.

Hind wing ( Fig. 15 ). Hind wing with two detached veins – R2 and R3, R2 half the length of R3, R3 and R5 long, almost touching the wing margin; R5 originating slightly behind the apex of R4; MA and CuA1 touching wing margin; MA and CuA1 almost equal in length. CuP close to anal margin and 1.5 times shorter than CuA1.

Legs ( Figs. 16–18 ). Fore coxa 0.22 mm long, fore femur 0.19 mm long, fore tibial length 0.18 mm, tarsomere I 0.07 mm, II 0.07 mm and III 0.05 mm long. Mid coxa 0.25 mm long, mid femur length 0.35 mm, mid tibial length 0.37 mm, tarsomere I 0.11 mm, II 0.11 mm and III 0.1 mm long. Hind coxa 0.18 mm long, hind femur 0.31 mm long, hind tibial length 0.38 mm, hind tarsomere I 0.12 mm, II 0.12 mm and III 0.1 mm long. Ventral surface on tarsomere IV hairy, without claws.

Abdomen. Abdominal segments sclerotized. Terminalia as follows: segment VIII distally tapered; sternite IX narrowed distally and bent ventrally at tip; aedeagus appended at the tip of sternite IX; Xth abdominal segment much longer bearing numerous long bristles at the distal end and extending beyond the base of aedeagus.

Aedeagus ( Fig. 19 ). Aedeagus 0.42 mm long with terminal hook 0.07 mm long, at ca. 36° angle with shaft; shaft stout, 0.28 mm long, bending basally into 0.08 mm long extension; base at ca. 63° angle with shaft.

Remarks. The proposed new species is included in the subfamily Halictophaginae owing to a simple head capsule without any suture and smaller body size (<2.5mm). It is included under the genus Halictophagus owing to presence of seven-segmented antenna with antennomeres III–VI flabellate, three-segmented tarsi without claws, hook- or anchor-like aedeagus and usually sclerotized mandible. The new species shows similarities to H. australensis Perkins (1905) in wing venation and shape of the scutellum but differs in antenna, maxilla, postlumbium, terminalia and aedeagus. Halictophagus prominens n. sp. bears similarities with H. orientalis ( Esaki & Hashimoto, 1931) in tarsomeres, but differs in antenna, maxilla, wing venation, shape of the scutellum and genitalia. The scutellum of the new species and of Halictophagus tenebrosus Chaudhuri, Ghosh & Das Gupta (1983) looks similar but differs in the structure of the aedeagus and hind wing. The new species draws affinities with Halictophagus trigondontos Cook (2013) in sclerotized, triangular mandible but distinct differences lie in the scutellum, wing venation and aedeagus. The new species comes nearer to H. forthoodiensis Kathirithamby & Taylor (2005) in wing venation but is different in postlumbium and aedeagus. In addition, H. forthoodiensis has a pseudopatella present on the fore tibia. Halictophagus prominens n. sp. is distinct in having abdominal segment X extending beyond the aedeagus with long bristles at the apex and a well developed heel-like base of aedeagus.

Female. Unknown.

Host. Unknown.

Figures

FIGURES 11 – 19. Halictophagus prominens n. sp., adult male. 11: antenna, 12: maxilla, 13: mandible, 14: metathorax in dorsal view, 15: right hind wing, 16: prothoracic leg, 17: mesothoracic leg, 18: metathoracic leg, 19: aedeagus.