Nimbamina Sáfián & Bartsch, 2022

Sáfián, Szabolcs & Bartsch, Daniel, 2022, Two new genera and species of Synanthedonini from the Nimba Mountains Liberia, West Africa (Lepidoptera: Sesiidae), Zootaxa 5141 (1), pp. 87-93 : 89

Nimbamina Sáfián & Bartsch gen. nov.

Type species: Nimbamina blei sp. nov., designated here.

Description. Head: haustellum well-developed; labial palpus long and thin, slightly curved upwards, first palpomere short, second and third palpomeres long, smoothly scaled, with some bristle-like scales distally; frons smooth and glossy; scales of vertex and pericephalic scales rather broad, smooth and glossy; antenna about as long as forewing, relatively thin, hardly clavate, distally moderately tapering; flagellum with short ciliae ventrally, dorsally with very long, tufted, proximally and distally tapering scales, tip without such scales. Thorax: very narrow, smooth, without hair-like scales. Legs: long and very thin, smoothly scaled; forecoxa about 4 times longer than broad; spurs long and thin. Forewing: hyaline; apical area absent; margins and discal spot narrow; veins R 1 to R 3 very close, R 4 and R 5 stalked to half their length; all veins from stalk of R 4 /R 5 to M 3 arising almost equally spaced from discocellular vein; CuA 1 and CuA 2 arising from common point. Hindwing: discal spot absent; vein M 2 arising from costad one third of discocellular vein, M 3 and CuA 1 with common stalk, CuA 2 arising distinctly proximal to discocellular vein. Abdomen: exceptionally long and slim, longer than hindlegs and more than twice as long as forewing, with extremely large, bipartite anal tuft. Female unknown.

Male genitalia ( Fig. 3 ). Genitalia capsule relatively weakly sclerotised. Tegumen about 1.2 times longer than uncus, both fused together; gnathos reduced to a small, ventro-distal hump only; uncus slightly elongated, triangular, distally pointed, ventro-lateral ridges densely covered with bifurcate setae, replacing scopula androconialis, distally very weakly sclerotised, pointed, with a few long setae. Juxta extremely wide, protruded. Valva narrow, elongate, outer two fifths 1.5 times wider than basal part, round-oval, dorsal margin concave in basal three fifths, ventral margin almost straight; inner surface sparsely covered with bifurcate setae, most sparse in middle part, with a bald area ventro-basally and on middle part of dorsal margin; crista sacculi lacking, replaced by a broad, oblique area of dense setae. Saccus as long as width of valva. Phallus very long, narrow and straight; vesica without thorns.

Diagnosis. Nimbamina is defined as follows: (1) body and legs extremely long and slender; (2) anal tuft exceptionally large; (3) antenna very thin, sub-distally hardly thickened, covered with very unusual long scales dorsally; (4) uncus pointed, with ventro-lateral rows of setae instead of scopula androconialis; (5) valva with unusual bald area on dorsal margin, widest in distal half, apically broadly rounded; (6) juxta extremely wide, protruded. We consider characters (2), (3), (5) and (6) to be the most important diagnostic characters of the genus.

This genus is unmistakable and cannot be confused with any other Sesiidae genera. Externally, the relatively small size, the extremely long and slender body, the huge anal tuft, the very thin legs without any tufted scales and the unique dorsal scales of the relatively long and thin antenna separate it well. More importantly, the new genus differs from all other genera of the family in the genitalia characters mentioned above. The tegumen-uncus complex is somewhat similar to that of Tipulamima Holland, 1893 , but the tegumen is proportionally longer and the gnathos is reduced. The valva and phallus are also distinctly different from Tipulamima : both are much narrower and the valva is distally broadly rounded, not pointed and without a crista sacculi.

Systematic placement. Based on the wing venation and the genitalia structure, Nimbamina gen. nov. clearly belongs to Synanthedonini . As already mentioned, it has a number of characteristics that are unique within the entire family and that do not clearly show any close proximity to one of the known genera. We suspect a relationship with Tipulamima , because of the rather similar shape of the tegumen-uncus complex. To clarify the correct association, however, further work, especially molecular-based research, and the still unknown female are required.

Derivatio nominis. Named after the Nimba Mountain range, which stretches across the borders of Liberia, Ivory Coast and Guinea. It harbours an outstanding biodiversity and numerous endemic Lepidoptera . The gender is feminine.

Figures

FIGURES 3–4. Genitalia structure and segment eight of Synanthedonini. 3. Nimbamina blei Sáfián & Bartsch sp. nov., holotype ♂ (vesica double the size). 4. Chlorosphecia bele Bartsch & Sáfián sp. nov., holotype ♂. Scales: 1 mm.