Tabwecala robinsoni, Zilli, 2021

Zilli, Alberto, 2021, Tabwecala robinsoni gen. nov., sp. nov., from Vanuatu and its systematic position in the ' Ophiusini - Poaphilini ' clade (Lepidoptera, Erebidae), Nota Lepidopterologica 44, pp. 193-211 : 193

Tabwecala robinsoni sp. nov.

Type material.

Holotype: Vanuatu • ♂; "New Hebrides", [Espiritu] Santo, Mt Tabwemasana Ridge; alt. 1372 m; 2 Sept. 1971; G.S. Robinson [leg.]; Roy[al] Soc[iety] Expedition; NHMUK010354772; NHMUK. Paratypes (3♂♂, 5♀♀): Vanuatu • ♂; same data as for holotype; NHMUK010918854; NHMUK • ♂; same data as for holotype; NHMUK010918855; NHMUK • ♀; same data as for holotype; NHMUK010354773; NHMUK • ♀; same data as for holotype; NHMUK010918853; NHMUK • ♂; Mt Tabwemasana, Nokowula; alt. 1128 m; 1 Sept. 1971; G.S. Robinson [leg.]; Roy[al] Soc[iety] Expedition; NHMUK010354774; NHMUK • ♀; same data as for preceding; NHMUK010918633; NHMUK • ♀; same data as for preceding; NHMUK010918636; NHMUK • ♀; same locality as for preceding; alt. “CK-“ 1067 m; 3-4 Sept. 1971; G.S. Robinson [leg.]; Roy[al] Soc[iety] Expedition; NHMUK010918856; NHMUK.

Etymology.

The species is dedicated to the memory of the collector of the type series Gaden S. Robinson (1949-2009), former researcher and curator of Lepidoptera at the then British Museum (Natural History). The specific epithet is a noun in the genitive case.

Diagnosis.

The new species looks superficially similar to species of the ophiusine genus Artena Walker, 1858, especially members of Artena rubida -group, namely A. reggiantii Zilli & Lourens, 2018, A. velutina (L.B. Prout, 1919) and A. rubida (Walker, [1863]), but is easily recognisable by the non-sexually dimorphic, slender rod-like third joints of labial palpi, rough instead of plain scaling of head and thorax, uniformly dark-coloured forewing without pale antemarginal field, larger, more centrally- and transversely positioned pale band of the hindwing and conspicuous scent tufts on the upperside of male metatibiae. Also somewhat resembling in habitus members of the poaphiline genus Achaea Hübner, 1823 and the yet incertae sedis genus Leistera Swinhoe, 1909, the latter showing another unusual combination of characters (type species, Catephia pulchristrigata Bethune-Baker, 1906, examined), e.g. no androteca as in Catephiini ( Berio 1992) but unlike these with spines on male meso- (weakly) and metatibiae, uncus with dorsal peak and valva structured as in several members of the Ophiusini + Poaphilini clade, including also single tubular dorsal corema from its base. Nonetheless, no Achaea species with forewing completely deprived of pattern are known to date, and the arabesqued ornamentation of forewing of species of Leistera will prevent any confusion.

Description.

Male (Fig. 1 ). Habitus. Wingspan 74.5-78 mm (mean = 76 mm, n = 4). Ground colour of head, body trunk and forewing uniformly dark blackish brown, with some scattered sprinkles of silvery scales. Forewing broad subtriangular with no evident pattern, apex smoothly rounded, termen overall slightly convex, feebly undulated at veins, anal margin straight, fringe concolorous with wing disc; hindwing broad and rounded, termen as in forewing but slightly produced at vein 1A+2A and with feeble white terminal line, colour dark chocolate brown, except for broad transverse white discal band, this widest at middle and with margins blurred, and with very feeble light-blue hue (visible if swinging the wing), ending before anal margin. Metatibial scent pencil blunt-ended and reaching in length almost the whole basal tarsomere, its basal third chocolate brown-coloured, mesially and distally brightly honey-coloured. Underside almost unicolorous dark blackish brown.

Male genitalia (Fig. 5 ). Tegumen high, very tapered superiorly, with small thorn-like projections before apex; vinculum semicircular; valva oblong-obovate, with hairy distal membranous section, sacculus small, lozenge-shaped, with small apical outwardly-produced horn-like process, ventral sclerotised part centrally positioned, in shape of wide-based sub-rectangular transverse plate ending distally into two processes, inferior one (interpreted here as a clasper proper) thumb-like, perpendicular to longitudinal axis of valva, and superior one (interpreted as of costal derivation) similarly shaped but longer and much stouter, subparallel to costal margin, with reclinate tip, inflatable saccate corema on dorsal side with thick tuft of long hair-like scales; uncus long and reclinate, bulbous at base, its dorsal process subbasal and horn-like with forward projected tip, distally sinuous with middorsal hump and downcurved pointed tip; tuba analis wholly membranous. Juxta narrow, sub-rectangular, slightly sinuous at sides, with slightly divergent projections at corners, the inferior pair articulated with valvae. Phallus bent at basal third, vesica small, with paired opposite long thin diverticula and central, slightly bilobed bulge protruding from central corpus.

Female (Fig. 2 ). Habitus. Wingspan 71.5-77.5 mm (x = 75.6 mm, N = 5). As in male, except for legs (described under generic diagnosis), and with white band of hindwing wider at middle of wing disc. Sternum A7 (lodix) posteriorly bilobate (Fig. 6 ).

Female genitalia (Fig. 6 ). Tergum A8 wide and short, its ventro-lateral belts facing the sternum about half as high as the dorsal part, long and with rounded ends, separated only by narrow sternal section, apophyses anteriores thin; basal sterigmatal plate broad and rugulose, trapezoid, its ventral longitudinal outgrowth narrow, sub-rectangular, posteriorly bifid with conspicuous, pointed asymmetrical processes, and with anterior excision extending posteriorly as a narrow furrow for about one third of its whole length, ostium bursae opening at bottom of short infundibular depression in correspondence of posterior end of midventral furrow, sternum A8 with narrow elongated sclerotisation proceeding from post-sterigmatal area. Ductus bursae very short, strongly sclerotised, joining with corpus bursae at junction between broad, dome-shaped cervix, which thus extends posteriorly to it, and large ovoid fundus bursae (note that the several irregular dark blotches visible in fig. 6 appear in completely other positions in another preparation, thus they seem tissue remains not pertaining to the bursa, though they appear tightly linked to it and not separable in the well cleaned preparations); appendix bursae conical. Intersegmental membrane A8-A9 short. Papillae anales elongated sub-rectangular, apophyses posteriores approximately 1.5 times as long as anteriores.

Distribution.

Currently known only from the island of Espiritu Santo in the Vanuatu archipelago.

Bionomics.

The original series was collected in a period of four days on the Mt Tabwemasana range, the highest peak of the island of Espiritu Santo and whole Vanuatu archipelago, at elevations between 1067 and 1372 m, which correspond to sites of Agathis - Calophyllum and montane cloud forests ( Munzinger et al. 2011).

Figures

Figures 1, 2. Habitus of Tabwecala robinsoni gen. nov., sp. nov., from Vanuatu, Espiritu Santo, Mt Tabwemasana. 1. Holotype ♂; 2. Paratype ♀. Scale bar: 1 cm (1, 2.).

Figures 5, 6. Genitalia of Tabwecala robinsoni gen. nov., sp. nov. 5. Male, paratype; 6. Female, paratype (sternum A 7 on left). Scale bar: 1 mm (5, 6.).