Gnathodes parallela, Elliott, 2024

Elliott, Imogen R., 2024, Five new species in the Afrotropical genus Gnathodes Whalley (Lepidoptera: Thyrididae, Siculodinae) with the description of the female of Gnathodes fiscinella Whalley, Zootaxa 5555 (2), pp. 253-268 : 255-257

Gnathodes parallela sp. nov.

(Figs 2, 12, 22)

Holotype, ♂, “ CAMEROON 900m / North Region, Wack ( La Falaise ) / 07°40’16.5”N, 13°33’18.4”E / 2-21.x.2018 Cold Cathode UV / Light Trap. / Safian, Sz., Simonics, G. Leg. / ANHRT:2018.36” // “ANHRTUK / 00234893” // “Gen. slide. No. / IE 83 / prep. by I. Elliott ” ( ANHRT).

Diagnosis. The two species presently included in the G. helvella species group, G. helvella (Fig. 1) and G. parallela sp. nov. (Fig. 2), are externally very different and can be distinguished by the ground colour of the wings, the former being yellowish brown and the latter, grey.

The male genitalia of both species are similar but with the following differences. Compared with that of G. parallela sp. nov. ( Fig. 12 ), the uncus of G. helvella ( Fig. 11 ) is more dilated medially (almost twice as wide at the widest point) and the valva is ca. 10% shorter. The proportions of the projections of the basal valval lobe differ, and in G. parallela sp. nov. the anterior projection is thicker and fused with the medial projection for a greater proportion of their shared length and an additional rounded basal lobe is present. In G. helvella , the postero-lateral arms of the gnathos ( Figs 11 , 21 ) are shorter (narrower apically and broader basally) and differ in the shape of the flattened basal plate, which is narrower and with defined lateral projections in G. parallela sp. nov. ( Figs 12 , 22 ), whilst it is larger and somewhat trapezoidal without lateral projections in the former species.

Description. Male (Fig. 2). Forewing length 8.0 mm. Head; vertex and frons pale greyish brown. Antenna yellowish brown, minutely ciliate. Labial palp pale greyish brown, strongly upcurved; first segment very short, same length as third, second segment three times length of third. Thorax greyish brown with dark brown patagium; tegula brown fading to pale yellow; mesothorax greyish brown. Foreleg dark brown, without spurs; midleg paler grey-brown, with one pair of spurs distally, outer spur two-thirds length of inner; hindlegs missing from holotype. Forewing upperside pale grey, paler basally, scattered with dark brown reticulation; costa flecked with small dark brown spots; medial area with an indistinct brown discal spot; termen pinkish, fringe pale grey to dark brown. Hindwing upperside with pinkish veins, pale grey basally, dotted with red scales medially. Forewing underside light grey with dark brown reticulation; costal margin very pale yellowish grey, flecked with dark brown spots; distal third of costa with vibrant orange-brown longitudinal streak subapically; veins Rs3 and Rs4 black, outlined with white; short and narrow brown streak perpendicular to Rs3 running to termen. Antemedial area with short black longitudinal line flecked with white, dorsad a reddish brown streak. Medial area with a distinct reddish brown, round discal spot. Tornus with a thick, quadrangular, dark brown patch. Hindwing underside as upperside, somewhat paler without pinkish hue. Abdomen; first and second abdominal segments pale greyish brown, subsequent abdominal segments dark greyish brown; genital capsule covered with yellow scales.

Male Genitalia ( Figs 12 , 22 ). Uncus elongate, gradually tapered distad with sclerotized ventral margin; distal half densely setose, apex pointed. Tegumen as tall as width of the valva with broad lateral plates. Gnathos highly modified with two long posterolateral arms arising from a flattened basal plate; arms narrow basally, strongly dilated medially, extending posteriorly into spiniform process, nearly as long as uncus. Juxta weakly sclerotized with two lateral lobules. Saccus narrow sclerotised loop, ventrally rounded. Valva broad at base, tapered medially; distal half with parallel margins, apical section somewhat dilated and evenly rounded with a subapical crest; costa very narrow. Sacculus moderately broad basally, tapered submedially, posteriorly produced into a short, spiniform process. Valva base bearing a highly modified lobe with three pointed lateral processes and a short rounded basal lobe anteriorly. Aedeagus tubular, slightly curved submedially, without coecum penis and carinal sclerotization. Vesica with fine scobination, without cornuti.

Female. Unknown.

Etymology. The Latin word parallela refers to the shape of the gnathos, bearing two long parallel posterolateral arms. An adjective in the nominative singular.

Figures

FIGURES 11–14. Male genitalia, a: clasping apparatus, b: aedeagus. 11. Gnathodes helvella, holotype male, BM Pyralidae slide No. 9599 (NHMUK). 12. G. parallela sp. nov. holotype male, Cameroon, gen. slide No. IE 83 (ANHRT). 13. G. fiscinella (male), Zambia, gen. slide No. IE 90 (ANHRT). 14. G. pallida sp. nov., holotype male, Liberia, gen. slide No. IE 86 (ANHRT).

FIGURES 21–22. Gnathodes helvella species group, details of the gnathos and basal costal process. 21. G. helvella, holotype male, BM Pyralidae slide No. 9599 (NHMUK). 22. G. parallela sp. nov., holotype male, Cameroon, gen. slide No. IE 83 (ANHRT).