Istrianis nigrosquamella Amsel 1959
Creators: name: Bidzilya, Oleksiy
name: Karsholt, Ole
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy

description: 18. Istrianis nigrosquamella (Amsel, 1959)
Pseudoteleia nigrosquamella Amsel, 1959: 31, pl. 5, figs 4, 5.
Istrianis nigrosquamella (Amsel, 1935): Bidzilya & Mey 2011: 205
Material examined. Holotype of nigrosquamella: ♂, IRAN, Khuzistan, Shadegan, 1.–10.iv.1956, Richter u. Schäuffele | Holotypus, ♂, leg. H. Amsel | Pseudoteleia nigrosquamella (gen. slide 317/ 14♂, O. Bidzilya) (SMNS). Paratypes: 1♀, IRAN, Khuzistan, Shadegan, 1.–8.iii.1956 (Richter) (gen. slide 318/14♀, O. Bidzilya) (SMNS); 1♂, same data as holotype, but 24.–29.ii.1956 (Richter) (GU 3459) (SMNK).
Other material. 1♀, IRAQ, Eshi Kelleb, 30.viii.1971, Populus euphratica, (gen. slide 407/14, O. Bidzilya) (BMNH).
Adult (Figs 43–47). Male. Wingspan 10.4–11.1 mm. Head whitish, segment 2 of labial palpus brown with white basal and medial ring, upper side off-white, segment 3 white with brown ring in middle and a few brown scales on apex; scape brown mottled with white, other antennal segments brown with white basal rings; thorax and tegulae black with a few grey and brown scales laterally. Forewing greyish brown, costal margin with small whitish diffuse spot in middle and larger whitish spot at 2/3; a few reddish-black raised scales at base, paired black dots surrounded with ochreous raised scales at base of cell, in its middle and in the corner, a few brown raised scales before middle below costal margin, white pattern extending from 2/3 width of base and gradually narrowed to apex along dorsal margin, apex mottled with white, cilia grey, brown-tipped; underside black from base to about 2/3 except for subcostal area; hindwing light grey, dorsal margin blackish brown both on upper and underside from base to middle, pencil of ochreous black hairs extending from base to about middle, cilia grey.
Female. As male, but forewing slightly broader, without whitish pattern along dorsal margin, underside in basal portion lighter, brown rather than black as in males; the abdominal segments I–IV black with white anterior margin.
Male genitalia (Fig. 78). Distal portion of tergite VIII tongue-shaped, nearly parallel-sided, two times longer than broad, posterior margin rounded, anteromedial emargination moderately broad, sternite VIII subequal in length to tergite VIII, about 2.5 times broader than long, posteriolateral projections distinctly prolonged; uncus weakly narrowed in apical 1/3, about half as broad as gnathos, apex rounded; gnathos longer than uncus, apex moderately broad, with strongly sclerotized narrow hook; tegumen boomerang-shaped, lateral lobes of even width, anteromedial emargination broadly rounded; valva weakly broadened apically; phallus moderately broad, apex rounded, longer than valva.
Female genitalia (Figs 105, 135, 136). Segment VIII trapezoidal, longer than broad; apophyses anteriores slightly longer than segment VIII, straight, tapered; anterior margin of sternite VIII with large broad anteriorly narrowed foamed lobes separated by deep triangular incision; posterior sclerite very small; anterolateral sclerite oxhorn-shaped; anterior sclerites short, leaf-shaped; subostial folds distinct; antrum tubular; ductus bursae long, narrow, broadened before globular corpus bursae; signum subhexagonal, posterior lobe narrow, anterior lobe two times broader than posterior lobe, medial emargination moderately deep, medial ridge interrupted in middle.
Diagnosis. Externally the holotype is very similar to I. squamodorella, but the head is white, rather than greyish black in the last mentioned species. There are also small differences in the underside of forewing: it is brown with black pattern from base to 2/ 3 in I. nigrosquamella and nearly entirely brown with black pattern only in apical 1/ 3 in I. squamodorella (see also under I. squamodorella). Amsel mentioned in the original description (1959: 31) that male hindwings of I. nigrosquamella are black to half length of dorsum, whereas hindwings of I. squamodorella are grey without black. We cannot confirm this: the males of I. squamodorella studied by us have hindwings distinctly mottled with black too. The male genitalia are most similar to those of I. kyrgyzsquamella in having a broad gnathos and the valva broadened apically; however, the apex of the gnathos in the latter species is broadly rounded, stronger sclerotized and with shorter hook, whereas the gnathos of I. nigrosquamella is more pointed and weakly sclerotized apically and the apical hook is longer and narrower.
The female genitalia can easily be recognized by the broad foamed anterior lobes of sternite VIII, separated by deep triangular incision.
Biology. Larvae feed on P. euphratica Oliv. The adults have been collected from late February to early April and then late August.
Distribution. SW Iran, Iraq (see also Amsel, 1949: 316, 1959: 32, Wiltshire, 1957: 137); Cyprus (?).
Notes. Pseudoteleia nigrosquamella was described from three specimens collected in Shadegan (Southern Iran) 1.–10.iv.1956 (male holotype), 1.–8.iii.1956 (female paratype) and 24.–29.ii.1956 (male paratype). The holotype differs from both paratypes externally in having whitish pattern along the dorsal margin of the forewing (absent in both paratypes). This character varies between male and females of the closely related I. squamodorella and we are therefore considering the female paratypes conspecific to the male holotype of I. nigrosquamella. However the absence of whitish pattern in the male paratype is problematic, as such variation among males has not been observed in other Istrianis species. Moreover the male paratype of I. nigrosquamella has no coremata. Taking into consideration the fact that members of type series were collected at different times and the above-mentioned suggestions, one can suppose that at least the male paratype of I. nigrosquamella is not conspecific with the holotype. Unfortunately the genitalia of the male paratype are rather uninformative, and additional material is needed to solve this problem.
A photograph of a male from Cyprus (Nikokleia, 70 m, 27.ix.2014, leg. I. Barton) resembles I. nigrosquamella. The specimen was unfortunately destroyed during shipment, and we are therefore unable to confirm its identity.
description: Published as part of Bidzilya, Oleksiy & Karsholt, Ole, 2015, Revision of the genus Istrianis Meyrick, 1918 (Lepidoptera, Gelechiidae) with special regard to the Palaearctic region, pp. 401-445 in Zootaxa 4059 (3) on pages 438-439, DOI: 10.11646/zootaxa.4059.3.1, http://zenodo.org/record/237390