Novilema bifurcum Durante, 2022

Durante, Antonio & Apinda-Legnouo, Emelie Arlette, 2022, Fifth contribution to the study of the Lithosiini of Gabon: two genera new for Gabon, with a description of two new species (Lepidoptera: Erebidae: Arctiinae), Zootaxa 5091 (3), pp. 416-428 : 424

Novilema bifurcum Durante new species

( Figs 6 , 11 )

Holotype: ♂, GABON, Ipassa (Makokou), 500 m, 0°30’43”N 12°48’13”E, 19/ 24-11-2017, Durante leg., gen. sl. n. 997 MAD, in coll. MSNS.

Diagnosis. The differences between Novilema bifurcum n. sp. and its congeneric N. fluminale in the shape and colour of the habitus are practically null, so the diagnosis is entirely based on the morphology of the genitalia.

The generic features are unmistakeably maintained, and it is thus very easy to assign this species as a Novilema (see Remarks below).

The main differences from N. fluminale are: the distal process of the ala valvae (sacculus) has a larger pincershaped bifurcation (slender in N. fluminale ); the apex of the supravalva is pointed (rounded in N. fluminale ); the juxta is Y-shaped at its distal end (not bifurcated in N. fluminale ).

Description. Wingspan ♂ 18.5 mm. Female unknown.

Head slightly paler than forewing upperside; antennae ciliated, dorsally same colour as the head, ventrally unpigmented; labial palpi porrect, not extending beyond the frons, slightly darker than the head.

Thorax. Anterior margin of the patagia slightly paler than forewing upperside; posterior area of the patagia, thorax, tegulae, legs and anal tuft same colour as the forewing upperside; spurs formula 0-2-4. Forewing upperside ground colour ochreous yellow, paler towards the termen. Forewing underside slightly darker than upperside, costa and inner margin paler. Hindwing upperside straw yellow with costal margin and apex darker. Hindwing underside same colour as upperside. Fringes concolorous.

Abdomen slightly pale.

Genitalia ♂. Uncus laterally compressed, ending in a point, pedunculated, rising from an unpaired semi-circular structure probably belonging to the cephalic margin of A10, possibly a socius ( Fig. 11B ); tegumen delicate, roughly triangular in dorsal view, with a bisinuated dorso-caudal margin; vinculum also delicate, with its arms approaching each other at the distal end (i.e. ventrally), assuming a bifid shape; saccus absent; juxta swollen at the basal 2/5, then protruding in a sturdy long stem ending in a fork; fultura superior a rod-like arched transtilla joining the opposite plicae centripetalis (sensu Birket-Smith 1965); manica penis ventrally sclerotized at the base, joining the juxta; valva overall quite slender; basis valvae curved ventrally, touching each other; supravalva membranous, distally gently tapering, with costa almost straight, producing a very smooth, slightly swollen processus distalis plicae in the middle; ala valvae fairly sclerotized, with sacculus slender and distal process curved over the supravalva and ending in a strong pincer; aedeagus half as long as the ala valvae, tubular, slightly bent, with coecum penis shallow, ductus seminalis inserted dorsally; vesica with a flat sclerotization (cornutus) on the left side and five sturdy thorn-like cornuti varying in size, three of which are aligned at the junction with the aedeagus on the right, the smallest on the dorsal lobe and the largest on the ventral lobe ( Fig. 11C ); finally, a scobination of small irregularly-shaped granicula on the distal surface between these last two cornuti ( Fig. 11D ).

Etymology. The species name, from the Latin “ bifurcus ”, means “forked” or “bifid”, and refers to the juxta and the distal process of the ala valvae, both ending in a fork.

Remarks. This Gabonese species is the second species included in the genus Novilema , previously described as monotypic from Nigeria on the type species Novilema fluminale . All the characters of the genus, as well as the supposed autapomorphies (i.e. the absence of valvellae and the long independent juxta; see Durante & Panzera (2001b: 466) and Krüger (2015: 46)), are clearly maintained: the generally slender valva; the bifurcated apex of the ala valvae process; the large uncus in lateral view; the valvae firmly juxtaposed to each other at the base; branches of the vinculum ventrally approaching each other without forming a saccus; the tubular aedeagus and the vesica with sturdy thorn-like cornuti.

Figures

FIGURE 11. Novilema bifurcum n. sp.—A–D: male genitalia. A: genitalia, aedeagus in situ; B: Uncus, socius and terminal portion of the juxta, enlarged; C: aedeagus, vesica everted, enlarged; D: granicula of the vesica, enlarged. ae: aedeagus; av: ala valvae; cr: cornuti; gr: granicula; ju: juxta; pav: distal process of the ala valvae; so: socius; sv: supravalva; te: tegumen; un: uncus; tr: transtilla; ve: vesica; vi: vinculum; VIII st: eighth sternum.

FIGURES 1–8. Lithosiini spp.: adults. 1, Pusiola unicolor n. sp.—holotype male. Gabon, Ivindo National Park. 2, ditto—paratype, male. Gabon, Ivindo National Park. 3, ditto—paratype, female. Gabon, Ivindo National Park. 4, ditto—paratype, female. Gabon, Ivindo National Park. 5, Pusiola celida—male. Gabon, Mondah forest. 6, Novilema bifurcum n. sp.—holotype, male. Gabon, Ivindo National Park. 7, Novilema fluminale—male. Gabon, Ivindo National Park. 8, ditto—male. Gabon, Ivindo National Park.