Exilisia ngai Volynkin, 2020

Volynkin, Anton V., 2020, Two new Exilisia Toulgoët, 1958 from mainland Africa (Lepidoptera, Erebidae, Arctiinae), Zootaxa 4768 (4), pp. 596-600 : 596-599

Exilisia ngai Volynkin , sp. nov. ( Figs 1, 2 , 7 )

Holotype ( Figs 1 , 7 ): ♂, “Nairobi, Dec. 1952, E. Pinhey ” / “Pres. by Coryndon Mus. B.M. 1961-696.” / label with QRcode “ NHMUK 010918143 ”, slide NHMUK010315783 Volynkin (Coll. NHMUK).

Paratype: ♂, Ngong, Nairobi, Oct.-Nov. 1954, Fowler & Coulson / Pres. by Coryndon Mus. B.M. 1961-696. / NHMUK 010918144 , slide NHMUK010315784 Volynkin (Coll. NHMUK).

Diagnosis. Exilisia ngai ( Figs 1, 2 ) is similar externally to the South African E. bipuncta ( Fig. 6 ) and the West Kenyan E. prominentia (illustrated by Kühne 2007: figs 152, 153) and can be distinguished from them by the genitalia structures only. The male genitalia of E. ngai ( Fig. 7 ) differs clearly from those of E. bipuncta ( Fig. 9 ; Kühne 2007: fig. 52) and E. prominentia (illustrated by Kühne 2007: fig. 53) by its longer and narrower left subapical costal process (that is broader and shorter in E. bipuncta and E. prominentia ), smaller right subapical costal process, more robust right apical costal process with a broad arrow-shaped tip (in E. bipuncta and E. prominentia that is narrow, finger like), and longer and curved right distal saccular process with a club-like broadened tip (that is short, directed distally and has a tapered tip in E. bipuncta and a foot-shaped tip in E. prominentia ). In addition, the band-like fused transtillae of E. ngai are longer and more heavily sclerotised, the left apical costal process is narrower, the left distal saccular process is well developed (that is absent in E. bipuncta ), and the right subapical saccular process is shorter and much broader compared to those of E. bipuncta . Compared to E. prominentia , the male genitalia of E. ngai is also characterized by its narrower tip of saccus, left distal saccular process being narrower basally and twisted and blunt apically (that is broad basally and thorn-like apically in E. prominentia ), and the presence of right distal and subapical saccular processes (both are absent in E. prominentia ).

Description. External morphology of adults ( Figs 1, 2 ). Forewing length 9.5– 10 mm in males. Male antenna weakly ciliate. Body monotonous hazel. Forewing narrow, with almost parallel margins and elongated apex. Forewing ground color pale hazel. Forewing pattern dark brown, diffuse. Antemedial line broad, V-like angled medially. Posterior part of medial area sometimes with intense brown suffusion connecting ante- and postmedial lines. Cell with blackish brown dots medially and distally. Postmedial line oblique, narrowed in the cell. Subterminal line slightly wavy, strongly broadened at anal wing margin and opposite the cell. Cilia hazel. Hindwing pale hazel with slightly darker brown suffusion in outer part. Discal spot diffuse, greyish brown. Cilia pale hazel with admixture of dark brown scales. Male genitalia ( Fig. 7 ). Uncus slender, slightly broadened medially and pointed apically. Tuba analis broad; scaphium broad, plate-like, heavily sclerotised, arrowhead-shaped; subscaphium broad, setose. Tegumen short, narrow, its distal half fused. Juxta weakly sclerotised, rectangular, with weak arcuate ventral crest. Vinculum short, saccus short, narrow triangular, with apically rounded tip. Transtillae broad, fused, setose. Valvae elongated, with almost parallel margins and strongly asymmetric processes. Left subapical costal process robust, long, slightly twisted, with strongly setose ventral margin and pointed tip; right subapical costal process very short, tuber-like, bearing a bunch of setae. Left apical costal process short, finger-shaped, directed ventro-distally; right apical costal process robust, long, its distal part asymmetrically arrowhead-shaped. Distal membranous lobes of valvae large, the right one significantly broader than the left one. Sacculus moderately broad, with weakly setose dorsal margin; right fold of sacculus much broader and more heavily sclerotised than the left one. Left distal saccular process short, slightly twisted, with tapered and rounded tip; right distal saccular process strongly elongated, curved dorsad, with club-like broadened tip. Aedeagus long, narrow, broadened proximally and slightly curved distally; vesica bears numerous small spinules.

Female unknown.

Distribution. The species is known from the vicinity of Nairobi ( Kenya) only.

Etymology. Ngai is the supreme god in traditional beliefs of peoples of Kenya.

Figures

FIGURES 1–6. Exilisia spp.: adults. 1, E. ngai, holotype ♂, Kenya (©NHMUK); 2, E. ngai, paratype ♂, Kenya (©NHMUK); 3, E. smithi, holotype ♂, Liberia (ANHRT); 4, E. smithi, paratype ♂, Liberia (ANHRT); 5, E. smithi, paratype ♀, Liberia (ANHRT); 6, E. bipuncta, lectotype ♂, S Africa (©NHMUK).

FIGURES 7–10. Exilisia spp.: male (7–9) and female (10) genitalia. 7, E. ngai, holotype, Kenya, slide NHMUK010315783 Volynkin (©NHMUK); 8, E. smithi, holotype, Liberia, slide AV5111 Volynkin; 9, E. bipuncta, lectotype, S Africa, slide BMNH(E) Arct. 494 (©NHMUK); 10, E. smithi, paratype, Liberia, slide AV5145 Volynkin.