Megatrabala, Takano & László, 2024

Takano, Hitoshi & László, Gyula M., 2024, Descriptions of new Hypotrabala Holland, 1893 (Lepidoptera: Lasiocampidae: Lasiocampinae: Selenepherini) in the collections of the African Natural History Research Trust, with notes on allied genera and the description of a new genus, Ecologica Montenegrina 72, pp. 19-63 : 26-27

Megatrabala gen. n.

https://zoobank.org/ urn:lsid:zoobank.org:act:84495382-BE93-4C6A-B28C-C3150022DF79

( Figs 2–4 )

Type species: Hypotrabala regalis Tams, 1953

Description.

Forewing length: male 34–36 mm; female: 53–54 mm.

Upperside. Ground colour yellow. Antenna bipectinate, brown; the rami shorter in females. Patagium, anterior section of prothorax and two tufts on posterior section of metathorax mahogany in males. Wings yellow, warmer in females; fasciae and markings mahogany. Forewing triangular, elongate; outer margin crenulate, produced at vein M2. Antemedial and postmedial fasciae bilineate, crenulate, interrupted and indistinct. Longitudinal band from base of costa, along the cubital and vein M3 tapering towards margin. Discal spot in males large, ovoid, pearlescent-white edged in mahogany, with a second, smaller more longitudinally elongate spot placed between it and the costa; in females small, reniform, mahogany. Subapical marking triangular, pointed distad, from vein R3 to M2 with darker greyish spots proximally in spaces R5 and M1. Tornal marking triangular, darker proximally. Termen with small lunules between veins giving margin a more crenulate appearance. Hindwing outer margin angled at vein Rs, gently arcuate and crenulate to tornus.

Underside. Ground colour as on upperside but paler in males. Fore- and midleg dark greyish brown, hindleg pale reddish-grey. Forewing fasciae absent. Discal spot weakly shows through from upperside; in males indicated by white scaling proximally. Subapical and tornal markings as on upperside but more diffuse and less well-defined.

Male genitalia. Uncus relatively short, broad at base, gradually tapered and slightly curved outward, apically pointed. Tegumen short and broad with narrow lateral plate. Valve bilobate, anterior lobe very short, triangular, moderately sclerotised, posterior lobe relatively long, narrow, strongly arched, apically pointed, heavily sclerotised. Juxta very short, relatively broad, anteriorly with shallow, broad depression. Vinculum very wide, medial section narrow ribbon-like with short membranous medial part; lateral plates large, rounded-triangular with slightly arcuate margins. Phallus very short, coecum penis relatively large, as long as sclerotised part of phallus, membranous sack-like, tightly attached to juxta; sclerotised section of phallus tapered distad, subapically abruptly curved dorsad, apically pointed. Vesica narrow tubular without inflated section, armed with a very long, robust, medially strongly curved, distally tapered, apically pointed cornutus. Eighth sternite with weakly sclerotised, relatively long and broad, somewhat triangular basal plate produced into a single heavily sclerotised, basally broad, distally tapered, elongate posteromedial projection bearing irregular, sharp marginal dentation.

Diagnosis. Both sexes of the type species are highly distinctive and can easily be separated from all known Hypotrabala species by their larger size, the yellow ground-colour, the crenulate outer margin of the forewing which is produced at vein M3, the longitudinal band that runs along vein M3 and the triangular subapical and tornal markings. In the males, Hypotrabala species possess only a single rounded or lunulate forewing discal spot lacking the accessory marking. The male genital configuration of Megatrabala supports a close relationship to Hypotrabala but in the latter, the valve is unilobate lacking the basal lobe, the vesica is inflated and often spherical with dentate crests and the eighth sternite is bilobate or bifurcate with smooth margins.

Derivatio nominis. The new genus derives its name from its large size and affinity to Hypotrabala .

Notes. The genus Megatrabala is currently considered monobasic containing only M. regalis ( Tams, 1953) comb. n. described from Kapanga in southern D.R. Congo. In the original description of the type species, Tams (1953) illustrated the genitalia and stated that the male genitalia are unlike any other species of Hypotrabala in having a single medial process of the eighth sternite. Although it is difficult to ascertain the shape and length of the socii or phallus, the fine quality of the photographic figure from a time when such figures were not commonplace, portrays the eighth sternite accurately ( Tams 1953: Fig. 5 ) when compared with a modern preparation ( Fig. 3 ).

Description of new species

Figures

Figures 2–4. Megatrabala gen. n. regalis (Tams, 1953): 2. ♂, Democratic Republic of Congo, Kapanga [NHMUK 010292326]. 3. ♂, id., genitalia (a: clasping apparatus, b: lateral view of phallus, c: eighth sternite). 4. paratype ♀, id. [NHMUK 010606816].

Figures 5–13. Hypotrabala species: 5. H. guttata (Aurivillius, 1915), ♂, Ivory Coast, Tai NP [ANHRTUK 00024479]. 6. Id., holotype ♂ of Pachymeta guttata Aurivillius, 1915 [NHMUK 010292296]. 7. H. magnimacula sp. n., holotype ♂. 8. Id., paratype ♂. 9. H. aurantiaca sp. n., holotype ♂. 10. Id., paratype ♂. 11. H. retorta sp. n., holotype ♂. 12. Id., paratype ♂. 13. Id., paratype ♀.