Rhytidothorax nigrum Singh & Agarwal

Hayat, Mohammad & Kazmi, Sarfrazul Islam, 2011, On some Encyrtidae (Hymenoptera: Chalcidoidea) from Namdapha Tiger Reserve in Arunachal Pradesh, India, Zootaxa 2830, pp. 1-19 : 9-11

Rhytidothorax nigrum Singh & Agarwal

(Figs 22–26)

Rhytidothorax nigrum Singh & Agarwal , [31. i] 1993a: 103, female, male. Holotype female, India, Assam, Haflong (FRI). Paratypes in ZDAMU. [Without description.]

Rhytidothorax nigrum Singh & Agarwal, [1. v] 1993b : 142, female, male, description.

Rhytidothorax nigrum Singh & Agarwal : Hayat, 1999: 395, actual date of publication. Hayat, 2006: 64, figures, key. Hayat & Khan, 2008: 127, female, male, Darjeeling (West Bengal) record.

Redescription. Female. Length, 1.90–2.27mm. Body dark brown to black, shiny; frontovertex bluish, slightly bronzy or purple in front of anterior ocellus; mesoscutum bluish green in some angles of light; scutellum with anterior third bluish green, posterior two-thirds bronzy violet; TI of gaster laterally with some purple luster. Antenna (Fig. 22) with scape brownish yellow, brownish towards apex; pedicel largely and F1–3 dark brown; F4 dark brown or pale apically, F5 usually yellow to pale yellow but sometimes brownish yellow, F6 yellow to pale yellow, and clava yellow to pale yellow with distal third to half with pale brown suffusions. Fore wing (Fig. 24) hyaline or subhyaline, with diffuse infuscation on disc; hind wing hyaline. Legs brownish yellow to pale yellow except mid coxa dark brown to black; tibiae with some brownish suffusions, and fore and hind tarsi brownish yellow.

Head. Frontovertex one-third of head width; eyes nearly reaching occiput posteriorly; antennal scrobes Ushaped, with rounded margins; antennal toruli with upper margins slightly above a line drawn across lower margin of eyes and separated from mouth margin by 0.6x torulus height; ocellar triangle with apical angle slightly obtuse; posterior ocellus close to eye margin than to occipital margin; POL 5.5– 6 x as long as OOL, and about 3x as long as OCL; frontovertex with slightly raised reticulate sculpture, and fine setigerous punctures, sparse on vertex, and in about two lines in front of anterior ocellus on each side of frons; setae on head brown; eyes setose, setae transparent, each clearly longer than a facet. Mandible with two pointed teeth and a small receding tooth, the middle tooth longest (Fig. 23). Maxillary palp 4-segmented, labial palp 3-segmented. Antenna as in Fig.22; scape about 7x as long as broad; pedicel about 3x as long as broad; F1slightly longer than to 1.3x as long as pedicel, and at least slightly more than 3x to 3.75x as long as broad; F2–6 longer than broad or only F6 sometimes quadrate; clava shorter than F4–6 combined.

Figures 22–26. Rhytidothorax nigrum Singh & Agarwal , female: 22, antenna; 23, mandibles; 24, fore wing; 25, fore wing, distal veins; 26, ovipositor.

Mesosoma. Mesoscutum with fine polygonal reticulations, the cells hardly raised, and with minute setigerous punctures; scutellum with raised reticulate sculpture except sides and apex smooth, the sculpture clearly deeper than on mesoscutum and frontovertex; setae on dorsum of thorax largely brown, mixed with silvery white especially on axillae and base of scutellum; propodeum median length 0.20–0.29x scutellum length, and with ridges mesally; sides of spiracles setose, setae silvery white; mesopleuron with fine reticulate sculpture; metapleuron along lower margin with lines of silvery white setae. Fore wing (Fig. 24) 2.5–2.65x as long as broad; stigmal vein always longer than marginal and postmarginal veins individually; postmarginal usually at least slightly longer than marginal vein (Fig. 25).

Gaster shorter than mesosoma (0.65–0.72x of mesosoma), apex rounded; hypopygium extending at least fourfifths length of gaster; hypopygium with a deep, semicircular notch in posterior margin; ovipositor as in Fig. 26.

Relative measurements (slide) — ovipositor length, 42; mid tibia length, 89; mid basitarsus length, 25; mid tibial spur length, 25.

Male. Described by Singh & Agarwal (1993b), and recorded by Hayat & Khan (2008).

Material examined. Type material: Holotype, FRI, 21220: on card, with parts on slide under 5 coverslips. Paratypes, ZDAMU, HYM. CH. 436: 1 female and 1 male on one card; one male on slide under 7 coverslips.

Non-type material: 4 females. INDIA: Arunachal Pradesh, Namdapha Tiger Reserve, Road to Ranijheel, 3 females (two on cards, 1 female with right antenna beyond F4 missing, second female with right antenna and right wings on slide No. EH. 1311; third female on slide (No. EH.1310) with right antenna beyond pedicel and left antenna beyond F1 missing), 11.xi.2009, P. M. Sureshan; 1 female (on slide, No. EH. 1309; clava of right antenna missing), Namdapha Tiger Reserve, Daphabum Road, 9.xi.2009, P.M.Sureshan. Two females (Slides, EH. 1309 and EH. 1310) in ZDAMU; 2 females, including slide EH.1311, in NZSI.

Host. Unknown.

Distribution. India: Arunachal Pradesh (new record); Assam; West Bengal.

Comments. There is some discrepancy between the published information on the type material and available specimens in the ZDAMU. Singh & Agarwal (1993a, b) noted that the holotype female is on a card and of the two female and two male paratypes, one female and one male paratypes were dissected and mounted on slides. The second female was ‘scanned (EM), silver coat removed by acid treatment and mounted along with other male’.

The holotype (on card with left antenna, left wings and legs of left side on a slide under 5 coverslips) was transferred to FRI (Accession No. 21220). Of the two female and two male paratypes, the ZDAMU has: 1) one female paratype (one fore wing missing, the other fore wing detached and glued on the same card) and one male paratype on one card; and 2) one paratype male on slide under 7 coverslips. Thus, one female paratype said to have been dissected and mounted on slide is missing.

The differences between R. nigrum and R. ramakrishnai sp. nov. are given in the key to species.