Idionyx gomantakensis, sp. nov.

(Plates 1–5)

Holotype (mature male in paper envelope): INDIA: Goa: South Goa district: Kulem (=Collem), N15.334°, E74.273°, altitude 103m; 13/VII/2008. Leg Parag Rangnekar. Deposited at Central Entomological Laboratory, National Zoological Collection, Zoological Survey of India, Kolkata-700 0 53, India. Reg. No: 4871/H13; Odonata Type Register Page No. 57, dated 05/10/2012.

Paratype (mature female in alcohol): INDIA: Goa: South Goa district: Kulem (=Collem): N15.334°, E74.273°, altitude 103m; 29/V/2012. Leg Rohan Naik and Parag Rangnekar. Deposited at Central Entomological Laboratory, National Zoological Collection, Zoological Survey of India, Kolkata-700 0 53, India. Reg. No: 4872/ H13; Odonata Type Register Page No. 57, dated 05/10/2012.

Specimens examined: One mature male and female with collection data as above. One more male was seen and photographed from the type locality but could not be captured (Plate 1F). Details of other specimens studied for comparison are provided in Table 1.

Description (Plates 1–5). Male holotype: Head: Eyes emerald green in life, brown in dry preservation. Frons tumid, pitted and shallowly grooved with metallic dark green colouration. Vertex metallic dark green; vesicle simple, oval and conical above. Labium, labrum, anteclypeus and postclypeus dull yellow. Median ocellus cream coloured. Thorax: Prothorax black with broad yellow stripe, covered dorsally with fine yellow pubescence. Pterothorax metallic green with fine yellow pubescence dorsally. Mesinfraepisternum and adjoining lowest part of mesepisternum brownish green, same colour continuing narrowly along humeral suture. Coxae and trochanters pale yellow, femora black, tibiae and tarsi pale yellow externally and black internally. Wings transparent and enfumed with amber brown at base. Antenodals 12–13 in forewings and 8 in hindwings. Postnodals 6 in forewings and 7 in hindwings. Hypertrigone with one crossvein in fore- and hindwings. Fore- and hindwings with one cubitoanal crossvein each, anal loop broad and seven celled. Membranule pale white. Pterostigma black, covering two underlying cells. Abdomen: Largely black, S7–9 broad, S1 and S2 black dorsally with ventrolateral pale yellow band, which extends as narrow ventrolateral line from S3–8. Intersegmental ring on S3–8 yellow and obscure. S10 has a mid dorsal crest. Anal appendages shaped as in Figs. 8–10, dark brown, long and narrow, lateral hooks with tuft of golden hairs at end. Accessory genitalia as in Fig. 11, light brown with apex of anterior hamulus, posterior hamulus and posterior lobe black. Genital lobe with tuft of golden hairs at end.

Female paratype: Head: Eyes emerald green in life, brown in wet preservation. Frons tumid, pitted and shallowly grooved with metallic dark green colouration. Vesicle simple, oval and conical above. Vertex metallic dark green. Labium, labrum, anteclypeus and postclypeus dull yellow. Ocellar tubercle cream coloured. Thorax: Pterothorax metallic green with fine yellow pubescence dorsally. Mesinfraespisternum and the adjoining lowest part of mesepisternum brownish green, same colour continuing narrowly among humeral suture. Coxae and trochanters pale yellow, femora black, tibiae and tarsi pale yellow externally and black internally. Wings transparent and enfumed with amber brown at the base. Antenodals 13 in forewings and 8–9 in hindwings. Postnodals 5–6 in forewings and 8 in hindwings. Hypertrigone with one crossvein in fore- and hindwings. Fore- and hindwings with one cubitoanal crossvein each, anal loop broad and eight celled. Membranule pale white. Pterostigma black, covering two underlying cells. Abdomen: Largely black, S1 and S2 black dorsally with ventrolateral pale yellow band, which extends as narrow ventrolateral line from S3–8. Intersegmental ring on S3–8 yellow and obscure. Valvula vulvae and appendages black, shaped as in Fig. 12. Apex of abdomen furnished with tuft of golden hairs.

Measurements (in mm). Male holotype hindwing 27, abdomen 25, total length (excluding anal appendages) 37. Female paratype hindwing 29, abdomen 29, total length 39.

Etymology: The species name gomantakensis is derived from the old name of Goa state where the type locality Kolem (=Collem) is located.

Diagnostic characters. Male I. gomantakensis is similar to I. corona in the absence of a row of teeth at the base of the cerci. However, it differs from I. corona by having long and slender superior cerci and epiproct; straight cerci and downwardly arched epiproct. In I. corona the cerci and epiproct are thick and curve inwardly. Moreover, in I. gomantakensis the lateral lobes of the epiproct have a tuft of golden hairs at the apex that is absent in I. corona. The female of I. gomantakensis is similar to I. saffronata and I. nilgiriensis in having a simple vesicle. However, it differs from female I. saffronata by having a conical vesicle and shallowly grooved frons. In I. saffronata, the vesicle is rounded at the apex and the frons is deeply grooved. The female of I. nilgiriensis has a swollen, rounded vesicle and deeply grooved frons.