Metarctia (Hebena) venustissima Kiriakoff, 1961

Fiebig, Ralf, László, Gyula M., Volynkin, Anton V. & Taberer, Tabitha R., 2023, Integrative taxonomic revision of the Metarctia Walker, 1855 subgenus Hebena Walker, 1856, with descriptions of six new species and one new subspecies (Lepidoptera: Erebidae: Arctiinae: Syntomini), Zootaxa 5339 (4), pp. 301-354 : 331

Metarctia (Hebena) venustissima Kiriakoff, 1961

(Figs adults 12a–b, genital 51)

Metarctia venustissima Kiriakoff, 1961 , Lambillionea 61(1–2): 10. Holotype male, type locality [ DRC] Katanga, Kolwezi (coll. RMCA).

Type material examined. Colour photo of the holotype, male, red oblong label “HOLOTYPUS” / [with partly handwritten] “COLL. P. HEBETTE Katanga: Kolwezi 18.11.1954. R. HUMPERS.” / [with handwritten] “T/60. Sp. nov. 6. Metarctia (Metarctia) sp. nov. Holotype”, GP LP147 ( RMCA) .

Taxonomic note. Despite the species’ habitus being typical of the subgenus Hebena (i.e. the dark forewing ornamented by contrasting reddish venation), Przybyłowicz (2009) followed the original combination of the taxon and treated M. venustissima Kiriakoff, 1961 as a member of the subgenus Metarctia . Although the configuration of the male genitalia of this species is unique in several aspects, the ground plan of the genital apparatus matches well with those of other Hebena . Hence, M. venustissima is transferred here from the nominotypical subgenus to Hebena : Metarctia (Hebena) venustissima Kiriakoff, 1961 .

Diagnosis. Metarctia venustissima is known from its male holotype only, providing thus very limited information about the habitus of the species without an opportunity to establish the extent of infraspecific variability. Based on the size of the holotype, the species is one of the largest taxa of the subgenus. The almost black ground colour and dark rusty-red venation of the holotype specimen renders M. venustissima the darkest species of the subgenus. The unique configuration of the male genitalia characterized by the rounded, semi-circular basal projection of the valva costa and the broadly rounded apex of the valva undoubtedly distinguishing it from all other Hebena taxa.

Description. Adult. Forewing length 25 mm in male holotype. Male antenna missing in the holotype, unexamined. Head. Small, proboscis small, labial palp short, rusty-red. Compound eye small, spherical, frons and vertex brick-red. Thorax. Collar dark rusty-red, tegula rusty-red with admixture of greyish hair-scales; mesothorax rusty-red. Legs. Coxa and femur covered in thick rusty-red hairs, tibia of fore- and midleg orange-red dorsally, black ventrally, tarsus entirely black, tibia and tarsus of hindleg entirely black; index of spurs: 0-2-2. Forewing. Moderately broad, elongate, dorsal margin almost straight, subapically slightly convex, apex rounded, outer margin long, evenly arcuate, anal margin short, almost straight. Ground colour dark-grey; veins covered in rusty-red scales; transverse lines absent except for narrow, rusty-red terminal line; fringe short, monochromatic dark fuscous-brown. Underside. Similar to upperside with more extensive ochreous suffusion in basal third. Hindwing. Well-developed, short and narrow, apically rounded, uniformly ochreous-yellow with very thin dark grey terminal line; fringe short, colour as of hindwing, except for dark brownish apical and dorsal part. Underside similar to upperside with more contrasting brownish veins and dark grey subapical suffusion. Abdomen. Stout, orange-brown.

Male genitalia. Uncus relatively long and narrow, medially dilated, dorsally evenly arched, apically pointed. Tegumen short and narrow, arms fused in distal half. Valva very broad at base, transtilla short, costal margin with a short and relatively long semi-circular basal projection without setae; distal section of valva short and broad, apically rounded. Sacculus short with relatively broad, sparsely setose rounded medial projection. Anellus (fultura superior) and juxta (fultura inferior) damaged in holotype, their shape could not be established. Vinculum long, Vshaped. Phallus short, thin and straight with coecum dilated and rounded, apex without carina. Vesica uneverted in the holotype specimen.

Female unknown.

Genetic information. Due to the age of the single known specimen of this species, DNA barcoding could not be carried out with the methodology applied in this work.

Distribution ( Map 5 ). Metarctia venustissima is known only from its type locality of Kolwezi in southern DRC.

Figures

MAP 5. Distribution of Metarctia (Hebena) venustissima.