Sontiha libera (Aurivillius, 1914)

Takano, Hitoshi, 2024, Descriptions of three new Sonitha Zolotuhin & Prozorov, 2010 (Lepidoptera: Lasiocampidae: Lasiocampinae: Gastropachini) from West Africa in the collections of the African Natural History Research Trust, with taxonomic notes on the genus, Ecologica Montenegrina 72, pp. 88-98 : 90

Sontiha libera (Aurivillius, 1914)

( Figs 1–3, 6 )

Stenophatna libera Aurivillius, 1914: 8 .

Sonitha libera (Aurivillius, 1914) : Zolotuhin & Prozorov, 2010: 425; Prozorov, 2016: 1103 (partim).

Description of male genitalia ( Fig. 6 ).

Socii as long as valve, basally fused, distal free sections digitiform and diverging. Tegumen with triangular lateral process. Valve short, narrow at base, tapering distad, apically curved dorsad and rounded at apex. Juxta with a pair of elongate triangular lobes. Saccus trilobed caudally. Phallus short, tightly attached to juxta; sclerotised section of phallus expanded distally. Vesica with short lateral diverticula, covered in ca. 30 long cornuti. Eighth sternite ovoid with two long, thin, apically pointed, diverging mediodistal processes.

Description of female ( Fig. 3 ).

LIBERIA: Nimba Mountains, Mount Gangra , western slope, 700m, 07°33’29.73”N, 08°38’16.4”W, 16– 17.iii.2017, leg. S. Sáfián & G. Simonics (1♀ ANHRT) .

Forewing length. 31 mm. Upperside. Ground colour of head, thorax and wings beige with pink irroration throughout; abdomen with darker brown scales. Antenna bipectinate, beige. Forewing angled at apex, outer margin broadly arcuate. Antemedial fascia curved, grey, angled at cell and vein CuA2. Discal spot small, black, ringed in pale pink. Postmedial fascia grey, arising midway along costal margin, gently crenulate to vein R5 where it angles sharply towards anal margin becoming strongly crenulate. Marginal area pale pink, delimited by a gently convex arc from apex to tornus. Fringe beige. Hindwing outer margin produced and sharply angled in space M2, straight and crenulate to tornal angle. Discal spot small, black, ringed in pale pink. Postmedial fascia almost straight, from two-thirds of the way along costa to midway along anal margin. Fringe brown. Underside. Ground colour similar to upperside but darker. Forewing apical and marginal areas with heavy suffusion of charcoal scales. Antemedial and postmedial fasciae, and discal spot absent. Hindwing with heavy suffusion of charcoal scales throughout. Postmedial fascia more diffuse running the same course as on upperside. Discal spot absent.

Diagnosis. In the males, S. libera is in general a smaller insect with forewing lengths of 18–21 mm (n=10) compared to 21–23 mm (n=13) in S. chocolatina . On the upperside, there is a greater suffusion of pink scaling in the former most noticeable on the forewing, thus contrasting less with the paler marginal band. The ground colour of the wings is a darker brown in the latter most noticeable basally on the hindwing upperside. Similarly, the underside ground colour is much darker brown in S. chocolatina whereas in S. libera there is a distinctive rosy hue. The male genitalia easily distinguish these two species: in S. chocolatina , the socii are considerably shorter, the triangular lateral processes of the tegumen are heavily reduced, the valves are hooked and apically pointed, the juxtal lobes are strongly dilated medially giving the impression of a ‘bird’s head’, the saccus is bilobed caudally, the phallus is longer, the vesica is bilobed with a long cornutus at each apex, and the processes of the trapezoidal eighth sternite are positioned laterodistally. In comparing the female of S. libera to the specimen of S. chocolatina figured in Zolotuhin & Prozorov (2010: Plate 23, Fig. 137 as S. libera ), the latter is darker brown in colouration with a better contrasting pale marginal area of the forewing and tornal area of the hindwing, the discal spots are white, and the hindwing outer margin is less produced in space M2 and less crenulate to the tornal angle. As these two species are distributed allopatrically, there is unlikely to be any confusion in specimens with good provenance.

Distribution. Liberia, Ivory Coast.

Figures

Figures 1–7. Sonitha species. 1. S. libera (Aurivillius, 1915), ♂, Liberia, Nimba Mts. [ANHRTUK 00261556]. 2. Id., holotype ♂ of Stenophatna libera Aurivillius, 1915 [NHMUK 014200366]. 3. Id., ♀, Liberia, Nimba Mts. [ANHRTUK 00056329]. 4. S. chocolatina Zolotuhin & Prozorov, 2010, ♂, Gabon, Mts. de Cristal [ANHRTUK 00204687]. 5. Id., ♂, id. [ANHRTUK 00129611]. 6. Male genitalia of S. libera, Liberia [HT 008]. 7. Male genitalia of S. chocolatina, Gabon [HT 006].