Omelko, Ponomarenko & Omelko & Omelko, 2021

Ponomarenko, Margarita G., Omelko, Michail M. & Omelko, Natalia V., 2021, New genus of gelechiid moths (Lepidoptera: Gelechiidae) from Borneo, and its four new species, Zootaxa 5004 (3), pp. 465-480 : 469-470

Tawaya Ponomarenko, M. Omelko , et N. Omelko gen. n.

Type species: Tawaya flaventia sp. n.

Diagnosis. The new genus is distinguished by the extremely small size of adults, which have a forewing length of 2.2–3.2 mm and a hindwing width of about 0.9 times its length. The intervals of wing indices (length to width at the middle ratio) in the new genus is 5.6–5.8 for forewings and 11.5–12.2 for hindwings, which is remarkably larger than any known representatives of any subfamily of Gelechiidae , with forewings 3.7–5.5, and hindwings 2.8–4.3. The new genus possesses a unique complex of characters in the male genitalia, the combination of which is found in no other gelechiid genera: short degenerative tegumen, rhomboidal or triangular in shape; uncus and gnathos absent; and well-developed parategminal sclerites present ( Figs 10–21 ). The well-developed parategminal sclerites are typical in shape of Dichomeridinae , their joining with the valva and tegumen along with their shape provide evidence that the new genus belongs in this subfamily. This assignment is also supported by molecular analysis.

Adult ( Figs 1‒7 ). Head pale sandy, sandy, light grey and grey. Antennal scape whitish, pale sandy, black, or yellowish brown; flagellum whitish, pale sandy, or yellowish grey, alternating with blackish grey or black. Basal segment of labial palpi very short, brownish or blackish; second segment brownish or blackish on outer surface, white distally; third segment shorter than second, whitish with two black rings near base and beyond middle. Labial palpus of some species with third segment black at apex.

Forewing length 2.2‒3.2 mm; forewing pale sandy, sandy, yellowish brown, or greyish-brown, with pattern consisting of indistinct blackish strigulae on proximal half of wing, and two black spots in pale border with small blackish strigulae below them on distal part of wing; a row of black dots along costal and outer margins in distal 0.3 of wing. Venation with Sc to costa at about 0.3 of wing length; R 5 and M 1 short-stalked, R 5 to costa before apex, M 1 to dorsal margin beyond apex; M 2 greatly reduced or absent; M 3 separate, close to CuA 1 basally; CuA 1 and CuA 2 separate basally, to dorsal margin; 1A+2A forked at base. Hind wing grey or brownish with concolorous fringe. Hindwing venation with Sc to costa beyond middle; Rs to apex, connate with M 1 basally; M 1 to termen, M 2 greatly reduced or absent; CuA 1 and CuA 2 from Cu stem separately, 2A short, to dorsal margin at 0.2 wing length ( Fig. 8 ). Legs pale sandy, sandy, or grey on outer surface with brownish, fuscous, or blackish, darkening, more intensive on fore- and midtibiae and tarsi of all legs; foreleg tibia with white spot on outer surface or one or two white oblique stripes at middle and white band distally on outer surface; mid-tibia with raised scales on lateral side in proximal 0.5, with rings of whitish and pale sandy scales in middle and distal parts; hind tibia with brush of hair-like brownishyellow, pale sandy, grey, or dark-grey scales on anterior margin and in proximal part on posterior margin; segments of tarsi of all legs whitish distally, two basal tarsomeres of hind tarsi with collar of long-stemmed scales distally.

Second abdominal sternite with relatively deep rounded incision between long well-developed apodemes, distinct long sinuous venulae and drop-like opening at the 0.7 distally ( Figs. 9 , 23, 28 ).

Male genitalia ( Figs 10-21 ). Uncus and gnathos absent. Tegumen extremelly short reduced, arched, nearly rhomboidal or triangular and hollowed posteriorly; joined to valvar basal processes (hemitranstilla) and parategminal sclerites (appendix appendicular sensu Hodges 1986). Cuculli with narrow distal part and more or less widened proximal part, often with dense patch of short, flattened scales along apex. Aedeagus almost straight, tubular, with ejaculatory ductus entering along longitudinal axis. Sacculi and juxta fused with vinculum into single large sclerite supporting and grasping aedeagus latero-ventrally. Two relatively long ventral processes, probably homologous to juxta, enveloping aedeagus laterally and joined to posterior margin of vinculum. Saccus well-developed.

Female genitalia ( Figs 22, 24, 26 ). Papillae anales slightly sclerotized, ovipositor moderate or short. Gland sack present distally on 8 th segment. Ostium near anterior margin or at level of middle part of 8 th segment, narrow, more or less sclerotized laterally, goblet-like or cup-shaped. Ductus bursae membranous and tubular, rarely with colliculum containing sclerotization. Bursae copulatrix membranous, lacking signum, ductus seminalis arising in its posterior part.

Distribution. Malaysia (Sabah).

Etymology. The generic name is derived from the city Tawau, in the vicinity of which much of the material was collected.

Figures

FIGURES 10–15. Male genitalia of Tawaya gen. n. spp. 10, T. flaventia sp. n., voucher V-MP-621, GS 153 MP; 11, T. flaventia, ventral view; 12, T. flaventia, dorsal view; 13, T. rutila sp. n., paratype, GS 155 MP; 14, T. rutila, ventral view; 15, T. rutila, dorsal view. aed—aedeagus, b.pr—basal process of valva, cl—cucullus, jux.pr—process of juxta, l.rid—longitudinal ridge of tegumen, p.scl—parategminal sclerite, sc—saccus, teg—tegumen.

FIGURES 16–21. Male genitalia of Tawaya gen. n. spp. 16, T. luteola sp. n., holotype, GS 157 MP; 17, T. luteola, ventral view; 18, T. luteola, dorsal view; 19, T. armeniaca sp. n., voucher V-MP-623, GS 154 MP; 20, T. armeniaca, ventral view; 21, T. armeniaca, dorsal view. Scale bar 0.1 mm.

FIGURES 1–9. Adults, wing venation and 2nd sternite of Tawaya gen. n. spp. 1, T. flaventia sp. n., holotype, male; 2, T. flaventia, paratype, female; 3, T. rutila sp. n., holotype, male; 4, T. rutila, paratype, female; 5, T. luteola sp. n., holotype, male; 6, T. armeniaca sp. n., paratype, male; 7, T. armeniaca, paratype, female; 8, T. flaventia, venation, voucher V-MP-621; 9, T. luteola sp. n., 2nd sternite of the female. Scale bar 0.5 mm.

FIGURES 22–28. Female genitalia, 2nd sternite and 7th abdominal segments of Tawaya gen. n. spp. 22, T. flaventia sp. n., paratype, GS 156 MP; 23, T. flaventia, 2nd sternite; 24, T. rutila sp. n., paratype, GS 159 MP; 25, T. rutila, 7th abdominal segment, paratype; 26, T. armeniaca, paratype, GS 158 MP; 27, T. armeniaca, 7th abdominal segment, paratype; 28, ditto, 2nd sternite, paratype. Scale bar 0.2 mm.