Dentadra stigmatismena, Volynkin, 2023

Volynkin, Anton V., 2023, Dentadra stigmatismena, a new species from Northeast India (Lepidoptera: Erebidae: Arctiinae: Lithosiini), Ecologica Montenegrina 69, pp. 135-139 : 136-139

Dentadra stigmatismena sp. n.

https://zoobank.org/ urn:lsid:zoobank.org:act:FF0EEAF4-6C1E-4B31-8F86-CF1BCE9BA31C

( Figs 1, 2 , 7 , 10 )

Type material. Holotype ( Figs 1 , 7 ): male, [Northeast India, Meghalaya, Khasi Hills ] “Khasis, | April 1897. | Nat. Coll.” / “Rothschild | Bequest | B.M.1939-1.” / QR-code label with unique ID “ NHMUK 010914122 ” / “Slide | NHMUK010315206 ” ( NHMUK).

Paratypes. INDIA: 1 male, 1 female, the same data as in the holotype, female with unique ID NHMUK010914122 and gen. prep. No. NHMUK010315207 ( NHMUK) .

Diagnosis. Dentadra stigmatismena sp. n. ( Figs 1, 2 ) is externally reminiscent of Z. khasiana ( Figs 5, 6 ), from which the new species differs in the shorter forewing with ochreous-yellow ground colour and a larger and distinct brown medial patch, and the unicolorous dark brown hindwing whereas in Z. khasiana , the forewing ground colour is ochreous with intense brown suffusion in ante- and postmedial areas, the medial patch is narrower and more diffuse, and the hindwing is paler and only slightly suffused with brown subbasally and along the anal margin. Despite the external similarity, the genitalia of both sexes of these species are fundamentally different ( Figs 7, 9 , 10, 12 ). Compared to the type species of the genus Dentadra , D. flavicosta ( Figs 3, 4 ), D. stigmatismena sp. n. has a yellow patagia (brown in the congener), a shorter forewing with yellow ground colour and three large and diffuse brown patches (subbasally, medially and postmedially; whereas the forewing of D. flavicosta is deep brown with a yellow costal stripe and an indistinct blackish-brown medial shade), and a smaller costal spot. In the male genital capsule, D. stigmatismena sp. n. ( Fig. 7 ) is distinguished from it congener ( Fig. 8 ) by the larger, bilobate cucullus (it is short protrusion-like in D. flavicosta ), the swollen and ovate medial costal process (it is thorn-shaped in the congener), and the narrower and markedly shorter sacculus having an apical thorn-like process but lacking denticles along its ventral edge, which are characteristic of D. flavicosta . Additionally, the uncus of the new species is proximally narower and apically broader than in D. flavicosta , and lacks the lateral lobes. The phallus of D. stigmatismena sp. n. is considerably shorter and narrower than in D. flavicosta , and lacks the carinal dentation. The vesica structure of the new species is substantially different from that of D. flavicosta due to the narrow and elongate main chamber lacking cornuti whereas in D. flavicosta , it is elliptical and bears two clusters of short triangular cornuti. The female genitalia of D. stigmatismena sp. n. ( Fig. 10 ) differ clearly from D. flavicosta ( Fig. 11 ) in the narrower, rounded and swollen postvaginal plate (it is rectangular and flattened in the congener), the considerably narrower ostium bursae, the markedly shorter and narrower ductus bursae with finer anterior dentation, the narrower and pyriform corpus bursae (it is sack-like in D. flavicosta ), and the shorter and conical appendix bursae, which is semielliptical in the congener.

Description. Adults ( Figs 1, 2 ). Sexual dimorphism limited: female with slightly longer forewing than male. Head ochreous yellow. Antenna ochreous yellow, ciliate in both sexes. Thorax deep brown. Patagia ochreous yellow. Tegula deep brown, edged with ochreous yellow. Forewing ground colour ochreous yellow. Antemedial area with triangular brown patch with irregular edge situated at anal margin. Medial area with blackish costal spot distally, and large, trapezoidal, brown medial patch between vein R and anal margin. Postmedial line with larger irregular brown patch medially-posteriorly and smaller trapezoidal subapical patch at costal margin. Terminal line brown, thin, disappearing at tornus. Forewing cilia ochreous yellow. Hindwing unicolorous dark brown, cilia brown with admixture of ochreous yellow. Abdomen brown with admixture of ochreous yellow scales. Male genitalia ( Fig. 7 ). Uncus broad and swollen, with almost parallel lateral margins, and apically rounded. Tegumen with broad arms fused in posterior quarter. Vinculum shorter than tegumen, with thin arms and short U-shaped saccus. Valvae lobular, proximally connected through membranous commissure. Costa broad, distally dilated and forming a broad and swollen, bilobate dog head-shaped cucullus. Medial costal process ovate, swollen, situated proximally. Sacculus broad, distally tapered, with rugose distal section having short triangular tip directed distally. Juxta elongate, narrow shield-like. Phallus short and relatively narrow, cylindrical, somewhat tapering distally, with short and rounded coecum. Vesica elongate and utricular, proximally upcurved, distally tapered and apically rounded, with short conical lateral diverticulum situated medio-proximally. Vesica ejaculatorius narrow, originating subbasally. Female genitalia ( Fig. 10 ). Ovipositor short. Papilla analis trapezoidal with rounded corners, weakly setose. Apophyses long and thin, equal in length, apophysis anterioris proximally broader than apophysis posterioris. Postvaginal plate rounded and swollen. Ostium bursae narrow. Ductus bursae short, anteriorly dilated, with tubular and membranous posterior section and anterior section bearing belt-like sclerotised plates with fine serrulation. Corpus bursae pyriform and membranous. Appendix bursae short, conical, membranous, situated postero-laterally on right side.

Distribution. Northeast India (Meghalaya).

Etymology. The specific epithet is derived from the Greek ‘στιγματισμένος’ meaning ‘speckled’ and refers to the spotted forewing of the new species. The name is a noon in nominative singular in apposition to the generic name.

Figures

Figures 1–6. Lithosiina spp.: adults. The specimens are deposited in NHMUK (©The Trustees of NHMUK).

Figures 7–9. Lithosiina spp.: male genitalia. Depositories of the specimens dissected: 7 and 8 in NHMUK (©The Trustees of NHMUK); 9 in MWM/ZSM.

Figures 10–12. Lithosiina spp.: female genitalia. The specimens dissected are deposited in NHMUK (©The Trustees of NHMUK).