Platyja cyanocraspis, Hampson, 1922

Zilli, Alberto & Vos, Rob de, 2021, The sumatrana species group of the genus Platyja with descriptions of four new species (Lepidoptera: Erebidae), Fragmenta entomologica 53 (2), pp. 391-410 : 396

Platyja cyanocraspis sub-group

Platyja cyanocraspis Hampson, 1922 (Figs 7-8, 21-22, 28) Platyja cyanocraspis Hampson, 1922 . The Bulletin of the Hill Museum 1 (2): 191. Locus typicus: Dutch New Guinea: Oetakwa River, Snow Mountains. Holotypus ♂ (by original designation), in NHMUK [examined] (Fig. 7).

Material examined. [ Indonesia] ‘ Dutch New Guinea’ [West Papua Province]: 2♀♀, Central Arfak Mts, Ninay Valley, 3500 ft, Nov. [19]08 to Jan. [19]09; in NHMUK ; [Papua Province]: holotypus ♂, Snow Mts. [= Maoke Mts], nr. Oetakwa R [iver], up to 3500 ft, x. xii.1910, Meek; 5♂♂, 7♀♀, idem; 1♂, Upper Setekwa R [iver], 2-3000 ft, Aug. 1910, A.S Meek; 2♂♂, 3♀♀, 25 miles south of Wangaar, Nomnagihé , 2000 ft, Jan.-Feb. 1921, C. F. & J. Pratt; these (9♂♂, 10♀♀) in NHMUK ; 1♀, Yahukimo District , in RMNH ; [ Papua New Guinea] ‘ British New Guinea’: 1♂, Hydrographer Mts , 2500 ft, Jan. 1918, Eichorn Bros., in NHMUK .

Distribution. Most records of Platyja cyanocraspis known to date are from the Indonesian side of New Guinea, from the Birdshead Peninsula (= Doberai, Vogelkop) to the Maoke Range, but a singleton from the Hydrographer Mountains (Owen Stanley Range) shows that this species is widespread in the island, where it also coexists and can be synchronically on the wing with its close relative (described below) ( Fig. 76 ).

Diagnostic remarks. Males of this and its sympatric sister species Platyja subtracta sp. n. (described below) are very similar in the habitus of the upperside, but they can immediately be distinguished by several features, above all the antennae, labial palpi, colour and shape of the discal spot of forewing, colour of androconial leg tufts and colour and pattern of the wings’ underside. In male P. cyanocraspis , the antennae are more slender and more darkly coloured, nearly black, the labial palpus is bigger, with the third joint almost as long as twice that of the other species, the reniform stigma is more deeply orange, thinner, straighter and more sharply defined, with a disjoint small lower spot, the postmedial line of forewing is distinctly angled between the discal cell and the apical area, and in both wings the adterminal band is more consistently tinged lilac; on the underside, the wings are deep black with no transverse lines and discal spots, and the legs are more weakly tufted with innermost (androconial) scaling of pro- and mesotibiae conspicuously yellow. Males are also weakier-bodied and more brightly coloured, sometimes with more vivid orangeish brown apical third of forewing. As regards the females, the best character to identify those of cyanocraspis is the trend of the crenulate postmedial line of forewing, which is more sharply angled beyond the reniform stigma, so that the external lobe of the median field is wider. Oth- er features are the pale adterminal band of forewing, that is narrower and crossed by a straighter continuous indigo midline, and the slightly narrower lilac stripe proximal to the same midline of the hindwing. The same basic differences between the reniform stigmata seen in males also apply to females, though in this case they are less evident because the filling colour is more weakly contrasting with the ground colour. On the underside, females of the whole sub-group do not show appreciable differences.

In the male genitalia (Figs 38-39, 61-62), clear diagnostic characters are found in the longer and broadly rounded apical saccular lobe of cyanocraspis , the trilobate cucullus, with longer, thinner and hooked apical process, the awl-like termination of phallus, which is stouter, thorn-like and externally flexed with respect to the sheath, and in the vesica, with numerous differences in the configuration and armature of diverticula. Among these, cyanocraspis shows a shorter and saccate main diverticulum anteriorly oriented from the vesica corpus, a longer and thinner, posteriorly directed diverticulum that is tipped by one cornutus only, and a median diverticulum which is also tipped by a cornutus, besides several differences in smaller lobes. In the female genitalia (Figs 67, 72), the overlap between the lodix lobes of cyanocraspis is less extended and the corpus bursae is more oblong, with less prominent and more anteriorly positioned cervical sclerotisation.

The same external differences occurring between cyanocraspis and subtracta are found in the other new species peripheral to New Guinea that are here described, due to the remarkable similarity of subtracta with these. Only exceptions are the colour of the scent tufts on legs, which also in P. vityaz sp. n. from the Bismarck Archipelago are as yellow as in cyanocraspis , the size of P. yaleyambae sp. n. from the Louisiade archipelago, whose individuals are quite small, and the terminal joint of the labial palpi, which are never as short as in subtracta . For the genitalia features of these species see under the relative descriptions.

Despite it has hitherto been considered as a subspecies of cyanocraspis , P. lecerfi stat. n. is very differently looking from cyanocraspis in the male sex, and cannot be confused because of outstanding differences in habitus and structural characters (see below). Females are as usual more similar, though the large size of those of lecerfi , their non-angular trend of the forewing postmedial and proximal lilac suffusion of the pale adterminal band of the hindwing that dilates superiorly will prevent any confusion between the two species, besides allopatry and the notable differences in the genitalia.

Morphological remarks. Variation has been observed in the width of valva between specimens from nearby localities.

Figures

Fig. 76 – Distribution of species of the Platyja sumatrana-group (populations from New Britain and Rook Island [= Umboi, Siassi] combined as vityaz s.l.; see explanation in text).