Gnathodes pallida, 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 : 257-259

Gnathodes pallida sp. nov.

(Figs 6, 14, 24)

Holotype, ♂: “ LIBERIA 551m / Wetezu camp, Wonegizi / Nature Reserve , Lofa County / 8°4’57.11”N, 9°34’47.86”W / 19- 27.iii.2019 Cold Cathode / UV Light Trap (8W) / Safian, Sz., Koivogui, S. Leg. / ANHRT:2019.7” // “ANHRTUK / 00143610” // “Gen. slide. No. / IE 86 / prep. by I. Elliott ” ( ANHRT).

Diagnosis. G. pallida sp. nov. (Fig. 6) is externally most similar to G. whalleyi sp. nov. (Figs 9, 10), sharing similar patterning on the forewing underside, expressed by the same greyish brown colouration with dark brown reticulations and pinkish hindwings. The notable differences include a greater coverage of dark brown reticulations on the upperside of the hindwings and the lack of bright red scales in the patterning on the underside of the forewing of G. pallida sp. nov. The male genitalia of both species are distinguishable in certain aspects of the gnathos: of the four posterior processes of the gnathos, one central and one outer process are partially fused in G. pallida sp. nov. ( Figs 14 , 24 ), whilst they are distinctly separate in G. whalleyi sp. nov. ( Figs 17 , 27 ); additionally, the antero-medial process of G. whalleyi sp. nov. is funnel-shaped whereas that of G. pallida sp. nov. is narrower and digitiform.

Description. Male (Fig. 6). Forewing length 9.0 mm. Head; vertex ochreous, frons brown. Antenna pale brown, minutely ciliate. Labial palp brown and strongly upcurved; first segment short, as long as third, second segment circa three times length of third. Thorax pale greyish brown, with narrow black patagium; tegula dark brown fading into pale greyish brown in basal area; mesothorax pale greyish brown. Foreleg dark brown, without spurs; midleg missing from holotype specimen; hindleg pale grey, with two pairs of spurs, outer spurs two-thirds length of inner. Forewing upperside pale yellowish grey with dark brown reticulations, costa marked with small spots; a transverse brown antemedial and postmedial band across two thirds of ventro-medial area; small, diffuse patches of brown scales lining ventral margin. Hindwing upperside pale yellowish grey with dark brown reticulation and some pinkish hue; two dark brown, transverse bands in medial section of anal margin; fringe dark brown, anal margin of hindwing with long, pale yellow piliform scales. Forewing underside ground colour pale yellowish grey; costal margin pale orange-hued, vibrant orange for apical third, lined with dark brown spots and flecks; antemedial area with a short orange-brown streak, capped with a black line flecked with white, underlined by a patch of dark brown scales; medial area with a reddish-brown blotch with three indistinct arms; veins Rs3 and Rs4 black outlined with white scales; subterminal area between Rs3 and Rs4 reddish brown, posteriorly merging with a brown subapical streak. Hindwing underside pale yellowish grey. Abdomen pale yellowish grey.

Male Genitalia ( Figs 14 , 24 ). Uncus elongate, gradually tapered distad with sclerotized ventral margin; distal half densely setose, apex pointed and slightly hooked. Tegumen half the length of valva, with very broad and rounded densely scobinate lateral plates. Gnathos highly modified and sclerotized, medially dilated and shield-like, with a prominent anteromedial process and two pairs of posterior processes, where lateral pair short and wide, fused with marginally longer digitiform medial process for around half their shared length, medial processes encompassing an excavation into central gnathos plate, not reaching the centre. Juxta two spiniform lobules. Saccus conical, almost as wide as gnathos, with squared-off ventral margin. Valva rounded basally, strongly tapered medially, dilated posteriorly, somewhat ovoid apically; costa straight and narrow possessing a highly modified arm-like basal lobe almost as long as gnathos, wide basally, narrowing medially, apically very narrow with a small, somewhat dilated and rounded tip. Sacculus moderately broad basally, tapered medially with sparse long setae subapically, posteriorly produced into a dilated spiniform process. Aedeagus narrow and tubular, without coecum penis and carinal sclerotization; vesica without cornuti.

Female. Unknown.

Etymology. The Latin word ‘ pallida’ refers to the paler colouration of the upperside compared to other species of the genus. 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 23–27. Gnathodes fiscinella species group, details of the gnathos. 23. G. fiscinella (male), Zambia, gen. slide No. IE 90 (ANHRT). 24. G. pallida sp. nov., holotype male, Liberia, gen. slide No. IE 86 (ANHRT). 25. G. ndoki sp. nov., holotype male, Republic of Congo, gen. slide No. IE 87 (ANHRT). 26. G. smithi sp. nov., holotype male, Liberia, gen. slide No. IE 91 (ANHRT). 27. G. whalleyi sp. nov., holotype male, Liberia, gen. slide No. IE 92 (ANHRT).

FIGURES 15–17. Male genitalia, a: clasping apparatus (left scale bar), b: aedeagus (right scale bar). 15. Gnathodes ndoki sp. nov., holotype male, Republic of Congo, gen. slide No. 87 (ANHRT). 16. G. smithi sp. nov., holotype male, Liberia, gen. slide No. IE 91 (ANHRT). 17. G. whalleyi sp. nov., holotype male, Liberia, gen. slide No. IE 92 (ANHRT).