Gnathodes smithi, 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 : 260-263

Gnathodes smithi sp. nov.

(Figs 8, 16, 26)

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 91 / prep by I. Elliott ” ( ANHRT).

Diagnosis. Whilst G. smithi sp. nov. (Fig. 8) is included within the G. fiscinella species group sharing some affinities with G. fiscinella (Figs 3–5), such as the characteristically shaped, shield-like gnathos ( Figs 23–27 ), it is more informative to discuss the differences between G. smithi sp. nov. and G. whalleyi sp. nov. (Figs 9, 10), as they are externally very difficult to distinguish from one another:

The external habitus of G. smithi sp. nov. (Fig. 8) is similar to that of G. whalleyi sp. nov. (Figs 9, 10), possessing pinkish hindwings and pale brownish grey forewings with dark brown reticulations. However, the foreand hindwings of G. smithi sp. nov. are more comprehensively covered with dark brown scales and the hindwings are flecked with reddish scales that are absent in G. whalleyi sp. nov. Additionally, the first two abdominal segments of G. smithi sp. nov. are pale yellow, whilst those are brown in G. whalleyi sp. nov.

The male genitalia of both species possess a highly modified, dilated and shield-like gnathos with prominent posterolateral arms and an anteromedial process, and an additional elongate basal costal process on the valva. Whilst the gnathos of G. whalleyi sp. nov. ( Figs 17 , 27 ) has two pairs of posterolateral arms and a funnel-shaped anteromedial process, the gnathos of G. smithi sp. nov. ( Figs 16 , 26 ) is simpler, somewhat horse-shoe shaped and only possesses one pair of posterolateral arms and a digitiform anteromedial process. The basal costal processes of the valva also differ: those of G. smithi sp. nov. occur as a dilated basal lobe with a very thin, elongate lateral process, whereas those of G. whalleyi sp. nov. are broader and more arm-like. The valval apices of G. smithi sp. nov. are also more evenly rounded.

Description. Male (Fig. 8). Forewing length 8.0 mm. Head; vertex and frons ochreous. Antenna minutely ciliate, basal section dark brown, faded into brownish yellow. Labial palp upcurved, pale yellowish brown; first segment short, as long as third, second segment three times length of third. Thorax yellowish brown, with narrow black patagium; tegula blackish basally, fading into pale yellow; mesothorax pale yellow. Foreleg brown, mid and hindleg pale yellowish grey; index of spurs 0-2-4; midleg inner spur three times longer than outer; hindleg spurs equal in length. Forewing yellowish brown, largely covered in dark brown contiguous patches; costal margin and basal area with pinkish hue; ventro-medial area with two transverse, dark brown bands; tornus with a dark brown streak. Hindwing yellowish brown, scattered sporadically with patches of red and dark brown scales; notable dark brown patches of scales present along medial section of anal margin; termen pale pink, fringe pale to dark brown at outer margin; anal margin with long greyish yellow piliform scales. Forewing underside with pale salmon pink costal margin flecked with small dark brown spots, apical quarter vibrant orange; antemedial area with narrow, somewhat triangular longitudinal orange streak, a black streak scattered with white scales dorsad; medial area with large red U-shaped blotch with a dark brown patch ventrad; veins Rs3 and Rs4 black, bordered with white scales; subterminal area between Rs3 and Rs4 red, merging with a short, brown subapical streak; a broad, somewhat quadrangular brown tornal patch present. Hindwing underside pale yellowish grey with dark brown reticulation. Abdomen; first segment with two brown lateral patches; second segment uniformly pale yellow; third segment yellow with brownish suffusion; segments four to eight dark brown; genital capsule covered by yellow scales.

Male Genitalia ( Figs 16 , 26 ). Uncus elongate, gradually tapered distad with sclerotized ventral margin; distal half densely setose, apically produced into very small, pointed and hooked tip. Tegumen half length of valva with densely scobinate broad lateral plates. Gnathos highly modified and sclerotized, half length of valva, somewhat horse-shoe shaped with a prominent antero-medial process; posterolateral arms apically rounded, encompassing a central depression with heavily sclerotized anterior margin. Juxta broad basally, bearing two anterolateral processes with some small spines around tips. Saccus as wide as gnathos, a gently rounded ventral margin. Valva relatively narrow and long, distal half sparsely setose; wide basally, tapered medially and dilated apically with evenly rounded apical margin. Costa straight and narrow with a prominent basal process almost as long as gnathos, comprising an ovoid lobe produced into an elongate, slender process extending over saccular process. Sacculus half length of valva, basally broad, medially tapered, with some long setae subapically and apically produced into a dilated spiniform process. Aedeagus tubular, without coecum penis and carinal sclerotization; vesica without cornuti.

Female. Unknown.

Etymology. It is with great pleasure that this new species is dedicated to Richard Smith, Chairman of the Board of Trustees, ANHRT, for his immense contribution to our knowledge of the entomological fauna of Africa. A noun in the genitive case.

Figures

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).