Siccasura Volynkin & László, 2021

Volynkin, Anton V. & László, Gyula M., 2021, Siccasura, a new genus for the Afrasura numida (Holland, 1893) species-group, with descriptions of six new species (Lepidoptera: Erebidae: Arctiinae: Lithosiini), Ecologica Montenegrina 40, pp. 1-25 : 2-3

Siccasura Volynkin & László , gen. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:CF85EDFF-1BEB-4EAA-B241-B6BB5BB9CE4E

Type species: Miltochrista numida Holland, 1893 by present designation .

Diagnosis. Adults of Siccasura ( Figs 1–24 ) differ clearly from most species of the genus Afrasura ( Figs 25– 30 ) except members of the Afrasura submarmorata species-group ( Figs 31, 32 ) which have similar wing pattern and colouration. However, Siccasura is distinguished from the latter taxa by the more contrasting forewing pattern, the presence of clusters of long black scales on the legs and the several dark grey spots along the outer margin of the hindwing which are much paler or absent in the A. submarmorata species-group.

The male genitalia of Siccasura ( Figs 33–50 ) display considerably diverse structures, but the genus is characterized by the combination of the following common diagnostic features: the sacculus is markedly wider than in Afrasura ( Figs 51–54 ); the vesica has a basal dentate plate (absent in Afrasura ) and lacks cornuti whereas it is armed with one robust cornutus or one or two clusters of spines in Afrasura . The configuration of the female genitalia of Siccasura ( Figs 55–66 ) displays even more conspicuous differences compared to other genera: the 7 th abdominal segment is heavily sclerotized, its tergite and sternite are fully fused laterally and the ostium bursae has sclerotized margins fused with the anterior section of the 7 th sternite, which is a unique, presumably autapomorphic character within the Asura / Miltochrista generic complex. A similarly sclerotized 7 th sternite is known only in the Asiatic genus Fossia Volynkin, Ivanova & Huang, 2019 ( Figs 70, 71 ), but in the latter the ostium bursae is positioned on the posterior margin of the 7 th sternite. Despite their somewhat similar configuration of the female genitalia, the imagoes and the male genitalia of Fossia ( Figs 67–69 ) and Siccasura are fundamentally different. Unlike in Siccasura , the 7 th tergite and sternite of Afrasura are weakly sclerotized and connected by a lateral membrane. The ostium bursae of Afrasura is positioned in the intersegmental area between the 8 th and 7 th sternites, its dorsal margin is fused with the 8 th sternite while the ventral margin is connected to the 7 th sternite by a thin membrane. Additionally, the corpus bursae of Siccasura is membranous, weakly spinulose or scobinated bearing only two weakly sclerotized rounded or ribbon-like signa bursae covered in tiny denticles while that of Afrasura has sclerotized plates of various shape and more extensive scobinated areas.

Remark. The species of the new genus are confusingly similar in external habitus and at the same time vary in size, forewing colouration and pattern even within the same population rendering the identification impossible based exclusively on external features. Reliable identification of the Siccasura species in all cases requires the examination of the genitalia.

Description. External morphology of adults ( Figs 1–24 ). Small moths with forewing length 6–8.5 mm in males and 7–9.5 mm in females. Sexual dimorphism limited: females slightly larger than males. Antennae of both sexes sparsely ciliate. Body ochreous-yellow, thorax with two black dots. Forewing ground colour ochreous-yellow with intense pink suffusion in medial and postmedial areas, transverse lines dark grey. Subbasal dot small and rounded. Antemedial line broad consisting of two lines and strongly undulating. Medial line sinuous, thin connected with postmedial line at costal and ventral margin and with antemedial line in the cell. Postmedial line wide, curved in the costal third, inner margin irregularly zigzagged, outer margin diffuse. Subterminal area with several diffuse black dots of different sizes. Discal spot reniform. Costa and cilia yellow. Hindwing pale ochreous-yellow but may be slightly pinkish. Medial line indistinct represented by a weak grey suffusion at costa. Terminal area with several diffuse dark spots of various sizes. Cilia as ground colour. Male genitalia ( Figs 33–50 ). Uncus long, thin, dorso-ventrally flattened and apically rounded. Tuba analis broad, scaphium thin. Tegumen relatively short, narrow and weakly sclerotized. Vinculum short and broad U-shaped. Juxta may be dorso-ventrally swollen or flattened, triangular or shield-like. Valva elongate with well-developed ventro-distal process and cucullus. In certain species, valvae asymmetrical expressed by different length of left and right valvae and configuration of the left and right sacculus and costa. Distal section of costal margin densely covered in spines of variable sizes or may be smooth in certain species. Cucullus well-developed, membranous, elongate and apically pointed. Ventro-distal process of valva long, narrow, heavily sclerotized and may be nearly straight or strongly curved. Sacculus wide, relatively short, terminating before the base of ventro-distal process. Aedeagus relatively short and narrow with short but laterally dilated coecum. Vesica broad with several small diverticula, a wide granulated or spinulose area, a heavily sclerotized basal plate but without distal plate. Basal plate covered in several tiny denticles. Female genitalia ( Figs 55–62 ). Papillae anales trapezoidal with rounded corners and weakly setose. Apophyses long and thin. Membrane between 8 th segment and papillae anales weakly granulated. 7 th segment heavily sclerotized, tergite and sternite laterally fused, sternite with short anterioventral fold. In certain species 7 th segment with dorso-lateral pockets and subostial lobes or sclerotized crests ventrally. Ostium bursae with sclerotized margins fused with 7 th sternite, aperture positioned posteriorly. Dorsal plate of posterior section of ductus bursae present in all species, short, reaching the posterior or middle third of ductus bursae. Postvaginal plate of various shapes in different species-groups. Antevaginal plate present only in S. spatulata and is horseshoe-shaped. Ductus bursae short, tubular, membranous, with spinulose scobination anteriorly or anterio-laterally, continuing into the posterior section of the corpus bursae where it widens. Corpus bursae elliptical, with two rounded or ribbon-like weakly sclerotized, spinulose signa. Appendix bursae membranous, conical, apically rounded and projecting postero-laterally.

Distribution. The genus is widespread in western and central Africa.

Etymology. Siccasura is an aggregate of the two generic names Siccia and Asura . The name refers to the vague similarity of the spotted wing pattern and the asymmetrical male genitalia of certain Siccasura species to those of Siccia .

Figures

Figures 1–8. Siccasura spp.: adults. Depositories of the specimens: 1 in CMNH; 2 in MWM/ZSM; 3, 4, 7 and 8 in ANHRT; 5 and 6 in ZSM.

Figures 9–16. Siccasura spp.: adults. Depositories of the specimens: 9–14 in ANHRT; 15 and 16 in MFN.

Figures 17–24. Siccasura spp.: adults. Depositories of the specimens: 17–22 and 24 in ANHRT; 23 in MWM/ZSM.

Figures 25–32. Afrasura spp.: adults. 25 and 26 are the type species of the genus. Depositories of the specimens: 25– 29, 31 and 32 in ANHRT; 30 in NHMUK (© The Trustees of NHMUK).

Figures 33–35. Siccasura numida: male genitalia. Depositories of the specimens: 33 in CMNH; 34 and 35 in ANHRT.

Figures 36–39. Siccasura spp.: male genitalia. Depositories of the specimens: 36 in ANHRT; 37 and 39 in MWM/ZSM; 38 in ZSM.

Figures 40–43. Siccasura sosta: male genitalia. Depositories of the specimens: 40–42 in ANHRT; 43 in MWM/ZSM.

Figures 44–46. Siccasura spp.: male genitalia. Depositories of the specimens: 44 in ANHRT; 45 in MWM/ZSM; 46 in MFN.

Figures 47–50. Siccasura spp.: male genitalia. The specimens are deposited in ANHRT.

Figures 51–54. Afrasura spp.: male genitalia. 51 is the type species of the genus. Depositories of the specimens: 51, 52 and 54 in ANHRT; 53 in NHMUK (© The Trustees of NHMUK).

Figures 55–60. Siccasura spp.: female genitalia. Depositories of the specimens: 55, 56, 58 and 59 in ANHRT; 57 in ZSM; 60 in MFN.

Figures 61–66. Siccasura (61 and 62) and Afrasura (63–66) spp.: female genitalia. 63 is the type species of Afrasura. Depositories of the specimens: 61–64 and 66 in ANHRT; 65 in ZSM.

Figures 67–71. Fossia spp.: adults (67 and 68), male (69) and female genitalia (70 and 71). 67–70 are the type species of the genus. Depositories of the specimens: 67 and 68 in NHMUK (© The Trustees of NHMUK); 69 and 70 in CKC; 71 in MWM/ZSM.