Acanthocorona, Mey & Léger & Lien, 2021

Mey, Wolfram, Leger, Theo & Lien, Vu Van, 2021, New taxa of extant and fossil primitive moths in South-East Asia and their biogeographic significance (Lepidoptera, Micropterigidae, Agathiphagidae, Lophocoronidae), Nota Lepidopterologica 44, pp. 29-56 : 37-38

Acanthocorona gen. nov.

Type species.

Acanthocorona skalskii sp. nov., Gender: feminine.

Etymology.

A noun composed of the Latin “acanthus”, thorn and the Latin “corona”, crown, alluding to the name Lophocorona and to the long spikes at the bases of the valvae and the spine and denticules on its apical margins, forming a spiny crown when the tips of the valvae are hold close together.

Diagnosis.

Burmese amber, small-sized species, antennae short, basal flagellomeres broad, epiphysis present, homoneurous venation, forewings with accessory and median cells present, cross-vein r1-r2 present, R 5 running to termen (below apex) in both wings; valvae of male genitalia with one or more pairs of long, basal spikes and a terminal, short, rod-like 'thorn'.

This fossil genus differs from extant homoneurous moths of Lophocorona by the presence of an epiphysis (absent in Lophocorona ), the presence of crossvein r1-r2 and the joint presence of an accessory and median cell (accessory cell may be present or absent in Lophocorona ). The valvae in the male genitalia carry a long, rod-like spine on the ventral tip together with numerous short denticules on the apical margin. In Lophocorona the spine on the ventral tip is small and blunt. The long spikes originating from the inner side of the base of the valvae can be regarded a synapomorphy of Lophocorona and Acanthocorona gen. nov.

Description.

Forewing length 3-5 mm, eyes hemispherical, frons and vertex with tufts of long piliform scales, ocelli absent; antennae short, about half the length of forewings, about 25-30 flagellomeres present, flagellomeres scaled on dorsal side, wider than long at base, becoming thinner and slender towards tip of antennae; proboscis present, dissociated into galea halves, maxillary palpi reduced in size, labial palpi upturned, terminal segment swollen, densely clothed by short bristles, tibial spurs 0.2.4., spurs covered by small scales, epiphysis present, legs slender (Fig. 26 ), with thin and strong spines on lateral and apical sides of tibiae, tips of tarsomeres with pair of short spines, ungues and arolium of praetarsus small; forewing venation (Figs 18 , 30 )) with Sc1 and Sc2, simple R 1, sectorial veins of R separate, originating from short accessory cell, R 5 terminating to termen shortly below tip of forewing; medial cell present, M4 absent; hindwings (Figs 18 , 30 ) with Sc and R 1 unbranched, accessory and medial cell open, base of costa with a number of short bristles; scales of forewing short and spatulate, or long with apical margins serrated, scales of fringes long, lanceolate, rounded at apex (Fig. 29 ).

Male genitalia (Figs 19 - 27 ): valvae elongate, band-like, of species-specific shape, with an erect and protruding rod-like, blunt process on ventro-distal corner, directed dorso-mediad, inner side of apical portion or apical margin with short denticules, bases of valvae with one, two or three long spikes, originating from knob-like protuberances or papillae on the inner side; median plate short, of different shape; dorsal median lobe of segment X present or absent, simple or bifid; phallic apparatus, if extruded, a long, slender tube, sometimes dilated on apex, gonopore in apical position.

Female genitalia (Fig. 31 ): sternum VIII with broad base and triangular ventral apex; segment IX fused with segment IX, oviscapt cone band-like, dorso-ventrally flattened, strongly sclerotized, fuscous to black, apex blunt, oviscapt saw usually hidden in oviscapt cone, sometimes protruding with its acute tip beyond cone margin.

Remarks.

Diagnostic characters of Lophocorona Common, 1973 are: 1) absence of an epiphysis, and 2) the long stalk of R 4 and R 5 in the forewings encompassing the wing apex. These characters are in a plesiomorphic state in Acanthocorona gen nov., with epiphysis present and R 4 and R 5 in the forewings always running as separate veins from accessory cell to wing margin. However, the structures of the male and female genitalia agree largely with those of Lophocorona . Especially the architecture of the female postabdomen is very similar to those of females of extant Lophocorona species ( Nielsen and Kristensen 1996). The nearly complete correspondence of this character complex with Lophocorona Common, 1973 provided the clue for identifying specimens in Burmese amber as lophocoronids. A correct association of males and females in Burmese amber is, however, a difficult venture. There are no unique characters other than genitalia, which would permit combining sexes. The structures of the female postabdomen are described in the generic description, but without assigning female specimens to one of the described males.

Burmese amber contains a surprisingly high number of species attributable to Acanthocorona gen. nov. The individuals are in most cases embedded in an unfavourable position and exhibit only a reduced number of characters. But none of the externally visible traits contradict the diagnosis and description of the genus. Cross-veins are often difficult to see and they may appear to be absent in some individuals. This uncertainty makes the character unreliable and reduces its taxonomic weight. The following species are described and included in Acanthocorona gen. nov. essentially on the basis of the male genitalia. The morphology and arrangements of spines and denticules on apical parts of the valvae constitute the principal character complex, which exhibits a large variety allowing the separation and establishment of different species. The following descriptions of new species are short and concentrate on the male genitalia and their illustrations. The depicted features are diagnostic enough to distinguish the presented species and to identify new species in fresh, additional material of Burmese amber, which hopefully will continue to become available for scientific study in the future.

Figures

Figures 26 - 31. 26 - 30. Acanthocorona spinifera sp. nov.: 26. Male genitalia, dorsal; 27. Ventral; 28. Legs; 29. Forewing scales; 30. Wing venation; 31. Acanthocorona sp., female (NIGP 173719), postabdomen, ventro-lateral view, and oviscapt tip, dorsal view. Scale bars: 0.5 mm (28.); 1 mm (30.); 0.8 mm (31.).

Figures 18 - 25. Acanthocorona spp.: 18 - 20. A. skalskii sp. nov.: 18. Wing venation; 19. Male genitalia, ventral; 20. Male genitalia, dorsal; 21. A. muelleri sp. nov., male genitalia, ventral, 22. A. bowangi sp. nov., male genitalia, ventral; 23. A. wichardi sp. nov., ventral; 24. A. kuranishi sp. nov., ventro-caudal, 25. A. sattleri sp. nov., male genitalia; A - ventro-lateral, B - dorso-lateral. Scale bars: 1 mm (18.); 0.5 mm (20., 22., 23., 25.).