Metarctia (Hebena) brigitta Fiebig, László, Volynkin & Taberer, 2023

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 : 321-322

Metarctia (Hebena) brigitta Fiebig, László, Volynkin & Taberer sp. n.

(Figs adults 6a–d, 18, 28; genitalia 45a–b, 55)

Holotype. male, “ Zimbabwe Nyanga Nat.Park 5.- 9.12.1993 leg.MEY & EBERT”, DNA barcode id.: BC ZSM Lep 111876, BOLD process id.: GWOUH480-21, gen. slide No.: GP 294.2019 ( RCRF, later MfN).

Paratypes (3 males, 1 female in total). Zimbabwe. 2 males, 1 female, same data as in holotype, DNA barcode id.: BC ZSM Lep 111873, BOLD process id.: GWOUC243-19, gen. slide No. : RF 283.2019 (female), RF 282.2019 ( RCRF, MfN); 1 male, “ Mashonaland. H.B. Dobbie. 1903-174”, QR code label with unique id.: NHMUK 010917765 , gen. slide No.: NHMUK 010315177 (LG 4702) ( NHMUK).

Diagnosis. Metarctia brigitta sp. n. is most similar externally to M. kelleni and M. elleni based on the grey fringe, the presence of the contrasting terminal line of the forewing and the narrow greyish dorsal area of the hindwing. It is, however, distinguished from these species by its considerably smaller size, paler ground colour and more broadly highlighted venation. The male genitalia of M. brigitta suggest a closer kinship to M. rubra and M. elleni based on the weakly setose costal projection of the valva and the wide distal valva margin between the terminal and costal processes. The new species is clearly distinguished, however, from M. elleni by the markedly shorter uncus, the considerably smaller, triangular costal process of the valva (it is long, digitiform in M. elleni ), the more concave distal margin of the valva and the much broader vinculum. Compared to M. rubra , the process of the valva costa of the new species is more acute and the terminal valva process is less robust. The female genitalia of M. brigitta is hardly distinguished from those of M. rubra , the only mentionable difference is found in the broader ostium bursae with more heavily sclerotized antero-lateral margin of the new species.

Description. Adult. Forewing length 24–26 mm in males, 25 mm in female. Male antenna bipectinate-ciliate, black, rami ca. 5 times longer than diameter of shaft, cilia very short, white. Female antenna serrate, rather thick, black. Head. Small, proboscis small, labial palp short, crimson, tip and dorsal side black. Compound eye small, spherical, frons and vertex crimson. Thorax. Collar crimson, tegula fuscous-brown with admixture of reddish hair-scales basally; mesothorax crimson with two fuscous longitudinal suffusions. Legs. Coxa and femur covered in thick salmon hairs, forelegs tibia with orange-red hairs, mid and hindlegs tibia and tarsus 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 graphite-grey; veins covered in salmon scales; transverse lines absent, except for narrow, salmon terminal line; fringe short, monochromatic grey. Underside. Similar to upperside with more extensive ochreous-orange suffusion in basal quarter and along costa, veins highlight broader, less contrasting ochreous-orange. Hindwing. Well-developed, short and narrow, apically rounded, pale salmon in dorsal-, darker in ventral half, with very narrow pale grey dorsal area; marking absent except for salmon terminal line; fringe short, pale ochreous, graphite-grey apically. Underside as upperside. Abdomen. Stout, pale orange, ringed with black proximally.

Male genitalia. Uncus short, subapically slightly curved, apically pointed. Tegumen short and narrow, arms fused in proximal quarter. Valva very broad at base, transtilla short, costal margin with a short, distally tapered, slightly outcurved, apically pointed basal projection with apex covered in few, short setae; distal margin long, concave, terminal process of valva short, basally broad, distally tapered, curved caudad, apically pointed. Sacculus short and narrow, bearing a relatively large, rounded triangular, setose distal crest. Anellus (fultura superior) and juxta (fultura inferior) fused, distal half inverse-triangular with narrow margins and broad postero-lateral corners, proximal half basally bifurcate, distally narrow, ribbon-like, inverse T-shaped. Vinculum moderately long, broad Vshaped with rounded apex. Phallus relatively long, thin, somewhat dilated proximally with short, rounded coecum, medially gently arcuate, apex without carina process. Vesica with slightly dilated proximal section bearing a small, finely spinulose subbasal field dorsally, distal section of vesica narrow, tubular.

Female genitalia. Papilla analis short, rounded-quadrangular, finely setose; posterior apophysis short (ca. as long as papilla analis), thin, pointed. Eighth tergite short, ribbon-like; anterior apophysis very short. Ostium bursae narrow with U-shaped sclerotized margin, lamella postvaginalis present, broad ribbon-like, longitudinally striate, interconnecting large, rounded triangular lamellae antevaginales. Ductus bursae narrow, short, tubular, distal half weakly sclerotized, proximal half membranous, cervix bursae unmodified. Tubular distal part of corpus bursae membranous, fourth as long as ductus bursae; dilated proximal section of corpus bursae large, ovoid; signum bursae represented by a very long, ovoid, finely scobinate field.

Genetic information. This species belongs to the BIN URI: BOLD:AEI8927. Due to the single DNA barcoded specimen, the infraspecific divergence could not be calculated. The nearest neighbour of M. brigitta is M. rubra with a pairwise distance of 2.35%. The species diverges from topotypical population of M. lateritia (BIN URI: BOLD:AAZ9706) at 6.22−6.98%, while the distance to the nominate taxon of M. smithi sp. n. is in the range of 5.56−6.62%.

Etymology. The species is dedicated to Brigitte Fiebig (Rossleben-Wiehe, Germany), mother of the first author, in gratitude for supporting his entomological research.

Distribution ( Map 2 ). Metarctia brigitta is known only from its type locality in eastern Zimbabwe.

Figures

MAP 2. Distribution of Metarctia (Hebena) rubra, M. (H.) manfredi, M. (H.) kelleni, M. (H.) elleni and M. (H.) brigitta.