Rubraea Henning, 1992

Williams, Mark C. & Henning, Graham A., 2023, Taxonomic revision of the tribe Acraeini Boisduval, 1833 (Papilionoidea: Nymphalidae: Heliconiinae), Metamorphosis 34 (1), pp. 35-49 : 38-39

Genus Rubraea Henning, 1992 stat. nov.

Type species Papilio egina Cramer, [1775] )

This is a purely Afrotropical genus of 39 medium- to large-sized species. The lineage arose ~ 18 Mya.

Body: Head large, broad and hairy. Antennae shorter than half length of forewing, averaging 47% (42-52%) of forewing for both sexes. Palpi 1 st joint twice as long as broad, 2 nd joint three times longer than first joint and terminal joint minute, oval. All joints hairy. Thorax short, compressed laterally, hairy and scaly. Abdomen long, extending beyond outer edge of hindwings, laterally compressed, broader distally. Legs: Anterior legs slender and less than half length of pterothoracic legs; tarsi of male single joint without spines, female tarsi five jointed with spines on each except last, no terminal spine. Pterothoracic legs, robust, external claw of male furrowed on inner surface, terminal claws asymmetrical. Wing venation: Radial veins of forewing not stalked; R 1 branching off from cell rather than stalked. Cell of hindwing about half of total wing length. Markings: Hindwing has the spots in the row below the apex joined to the central row creating a discontinuous arrangement of spots (7:2 configuration). Hyaline areas and hyaline patches not present. There are no marginal markings or spots on forewing upper side. Male genitalia: Uncus short, acute or bifid at tip; aedeagus long, narrow but not needle like, distally thin in one species group with broad truncate base, all basally bifid into two prongs; sclerotized and modified 8th tergite present; valves large, distally obtuse or elongate with distal processes; juxta elongate, triangular, weakly sclerotized; vinculum fairly broad; saccus very broad. Female genitalia: Anal lobes small, evenly rounded, posterior apophyses as long or longer than the lobes; sterigma convex, U-shaped; ostium centrally or anteriorly placed; ductus very short; bursa spherical; single pair of signa very small or absent. Sphragis present except in A. acrita species group.

Early stages: Egg elongate; laid in clusters, sometimes

singly ( R. nohara ). Larvae gregarious; dorsal spines on segments 3-6 sometimes longer and thicker. Pupa with wing covers finely lined by black on wing veins. Host plant genera: Tricliceras and Basananthe (4 records each), Adenia and Oncoba (3 records each), Rawsonia (2 records). One record each for Triumfetta , Drypetes , Rinorea , Caloncoba and Xylotheca . Host plant families: Passifloraceae (6 records), Salicaceae , Turneraceae and Achariaceae (3 records each), Malvaceae , Euphorbiaceae , Violaceae and Flacourtiaceae (1 record each). Habitats (biomes): Predominantly a woodland genus, with five species in grassland. Woodland (14 spp.), forest (7 spp.), grassland (5 spp.), submontane forest (1 sp.) and coastal forest (1 sp.). Geographical range: Rubraea is confined to the sub-Saharan African mainland, with a few species in the Gulf of Guinea islands. The genus is concentrated in east-central Africa (eastern and southern DRC, Tanzania, Zambia and Angola).

Diagnosis

Facies: Rufous to ochreous with black spots. Hyaline areas or patches are absent. The genus Rubraea can be distinguished from Stephenia by their generally less acute forewings.

Genitalia: The male genitalia in Rubraea have the aedeagus long, narrow but not needle-like; distally thin in one species group with broad truncate base, all basally bifid into two prongs; sclerotized and modified 8 th tergite present; valves large, distially obtuse or elongate with distal processes. In the female genitalia the sterigma is convex, U-shaped, with the ductus very short.

Species list