Archithosia (Acanthosia) oblonga Durante & Potenza, 2025

Durante, Antonio, Potenza, Luigi & Pellegrino, Gabriele, 2025, Revision of the subgenus Acanthosia Krüger, 2015 in the genus Archithosia Birket-Smith, 1965, with a description of four new species (Lepidoptera: Erebidae: Arctiinae: Lithosiini), Zootaxa 5659 (3), pp. 407-425 : 415-417

Archithosia (Acanthosia) oblonga Durante & Potenza sp. nov. ( Figs. 5C ; 7C–F )

Holotype: ♀, GABON, Ipassa (Makokou), 500 m, 0°30'43"N 12°48'13"E, 16/ 21-6-2016, Durante & Fasiello leg., gen. sl. n. 1207 MAD; in coll. MSNS.

Paratype : ♀, GABON, same data as the holotype, 14/ 24-3-2015, Durante leg., g. sl. n. 1285 MAD ; in coll. MSNS.

Diagnosis. This species, very similar to all congenerics, is potentially easily discernible by means of the smaller size of the costal black dot on the forewings (this, however, needs to be validated by a more significant number of observations) The most reliable feature is genital morphology: the shape of the sterigma is unique in the whole genus, with two almost superimposed U-shaped structures (the VII sternum posterior margin—external—and the lamella antevaginalis—beneath). It might be possible to add the oval corpus bursae (too thick to be an artefact, as might result for instance from a hypothetically pressed spherical corpus), the slender ductus and the very short anterior apophyses.

Description. ( Fig. 5C ). Wingspan ♀ 28.5 mm. Head ochreous yellow; antennae ciliated, dorsally same colour as head, ventrally unpigmented; labial palpi porrect, not extending beyond frons, same colour as head, with distal segment beige.

Patagia, tegulae and notum ochreous yellow, thorax ventrally light beige; patagia and tegulae somewhat darker in middle. Legs same colour as thorax sternites, but forelegs darker, mid- and hindlegs lighter, internally ochreous yellow; spurs formula 0-2-4. Forewing upperside ground colour beige-dusted ochreous yellow with one black dot at middle of costa and one smaller dot in middle of space between veins CuA2 and 1A+2A. Forewing underside unmarked, light beige with margins ochreous yellow. Hindwing upperside and underside unmarked, ground colour straw yellow with slightly darker margins. Fringes concolorous with margins.

Abdomen same colour as thorax sternites,with anal tuft slightly lighter.A2 sternum apodemes long(plesiomorphic character according to Bendib & Minet (1999: 243), but see also Holloway (2001: 281)). Seventh abdominal sternite slightly longer than sixth; seventh tergite twice as long as sixth. Eighth abdominal sternite coincident with lamella postvaginalis; eighth tergite about 1/5 as long as seventh tergite.

Genitalia. ♀ ( Figs. 7C–F ). Seventh sternite slightly sclerotised, with caudal margin (ca) swollen in a broad U-shape, covering a large well sclerotised lamella antevaginalis (la) with same shape. Eighth sternite coincident with lamella postvaginalis (lp), contiguous with lamella antevaginalis, well sclerotised, also in a broad U-shape, bearing caudally a smaller U-shaped sclerotization (us), protruding ventrally. The two lamellae compose an annular sterigma around the ostium with no clear distinction between ante- and postvaginalis.

Papillae anales (pa) smoothly squarish (in pictures appearing to taper caudally due to rolling of ventral caudal corners); anterior apophyses (aa) about 1/3 shorter than posterior apophyses (pp); posterior apophyses slender, a bit longer than papillae anales; dorsal pheromone glands (pg; Fig. 7D ) unpaired, with one caudal opening at intersegmental membrane between A8 and A9, anteriorly deeply bifurcated into two finger-like lobes as long as papillae anales.

Ductus bursae ( Fig. 7E ) slender, membranous, as long as corpus bursae, with some sclerification (sc) in the posterior half and ductus seminalis (ds; Fig. 7D ) arising dorsally from caudal end; corpus bursae (cb) oval, membranous, internally covered in tiny spines; signum (si) roundish, concave, strongly sclerotised, scobinate, with surrounding area also scobinate ( Fig. 7F ).

Etymology. The name of this species derives from the Latin “oblongus”, meaning elongated and referring to the oval corpus bursae along the longitudinal axis.

Figures

FIGURE 5. Archithosia (Acanthosia) species. A. A. flavifrontella, male, g. sl. n. 1251 MAD, Ipassa, Gabon. B. A. flavifrontella, female, g. sl. n. 1318 MAD, Ipassa, Gabon. C. A. oblonga sp. nov., holotype, female, g. sl. n. 1207 MAD, Ipassa, Gabon. D. A. brevis sp. nov., holotype, female, g. sl. n. 1280 MAD, Ipassa, Gabon. E. A. tryphosa, holotype, male, Arctiidae genitalia slide n. 44 BMNH, Ruwenzori Range, Bwamba Pass, Uganda. F. A. parva sp. nov., holotype, female, g. sl. n. 1218 MAD, Ipassa, Gabon.

FIGURE 7. Archithosia (Acanthosia) species, genitalia. A. A. flavifrontella, female, ventral view, g. sl. n. 1207 MAD, Ipassa, Gabon; B. A. flavifrontella, female, ventral view, teratological form, g. sl. n. 1283 MAD, Ipassa, Gabon; C. A. oblonga sp. nov., holotype, female, ventral view, g. sl. n. 1207 MAD, Ipassa, Gabon; D. Same, dorsal pheromone glands, dorsal view; E. Same, ductus bursae, dorsal view, enlarged; F. Same, signum, ventral view, enlarged. aa anterior apophyses; ca caudal margin of VII sternite; db ductus bursae; ds ductus seminalis; cb corpus bursae; la lamella antevaginalis; lp lamella postvaginalis; pa papillae anales; pg dorsal pheromone glands; pp posterior apophyses; sc sclerifications of ductus bursae; si signum; us Ushaped sclerotization of VIII sternite; VIII t eighth tergite.