Brunia vestigialis, Volynkin, 2022

Volynkin, Anton V., 2022, A review of the genus Brunia Moore from the Andaman Islands (India) with a description of a new species (Lepidoptera: Erebidae: Arctiinae), Ecologica Montenegrina 59, pp. 82-91 : 83-85

Brunia vestigialis sp. n.

https://zoobank.org/ urn:lsid:zoobank.org:act:70A81094-5747-4579-A5F2-597A3E4441C9

( Figs 1–3 , 17 , 23 )

Type material. Holotype ( Figs 1 , 17 ): male, “ India – Andaman Isl. | Middle Andaman | Mayabander · 19.– 20.iii.1998 | leg. A.Kamenev & V. Siniaev | ex coll. Dr. A. Schintlmeister ” / “Slide | ZSM Arct. | 2021- 268♂ | A. Volynkin ” ( MWM / ZSM).

Paratypes. INDIA, ANDAMAN & NICOBAR ISLANDS: 1 male, 2 females, the same data as in the holotype, gen. prep. Nos.: ZSM Arct. 2021-269 (male), ZSM Arct. 2021-272 (female) (prepared by Volynkin) ( MWM / ZSM); 1 male, North Andaman , Mayabunder, 6 km S; Karmatany – rainforest, 12°50'6[5]1''N, 092°56'06''E, 17–21.XI.2000, J.-P. Rudloff leg., gen. prep. No.: ZSM Arct. 2021-010 (prepared by Volynkin) ( MWM / ZSM) .

Diagnosis. The male of B. vestigialis sp. n. ( Figs 1, 2 ) is externally reminiscent of B. gibonica ( Figs 4–6 ) and B. nebulifera ( Fig. 8 ) but distinguished by the ochreous forewing ground colour (it is ochreous-yellow in B. gibonica and yellow in B. nebulifera ), the markedly smaller and more diffuse distal shade of the forewing, and the somewhat darker hindwing. The female of the new species ( Fig. 3 ) is clearly different from both the similar congeners ( Figs 7, 9, 10 ) due to the dark brown forewing ground colour with a broad pale yellow costal stripe but whereas the females of B. gibonica and B. nebulifera are similar to the males and have only broader subapical shades of the forewing. The female of B. vestigialis sp. n. is more similar to the sympatric B. antica ( Fig. 16 ) but differs in the smaller size, the more apically rounded forewing with a darker brown ground colour, and the somewhat broader yellow costal stripe, which is broader apically. The male genital capsule of the new species ( Fig. 17 ) is similar to B. gibonica ( Fig. 18 ) and B. nebulifera ( Fig. 19 ) but distinguished by the thinner, thorn-shaped and distally upcurved distal saccular process, which is swollen and with a short triangular tip in the congeners. The phallus of B. vestigialis sp. n. is somewhat more dilated distally than in B. gibonica and B. nebulifera . The vesica configurations of the three species are similar but in B. vestigialis sp. n., the dorsal chamber is somewhat broader, lacking the diverticulum, and bearing a straight cornutus with a markedly broader base whereas it is somewhat curved, shark tooth-shaped in B. gibonica and almost conical with a narrow base in B. nebulifera . Additionally, the ventral diverticulum of B. vestigialis sp. n. is somewhat broader than in B. gibonica and has a slightly broader distal lobe. Compared to the new species, the ventral diverticulum of B. nebulifera lacks the cornutus and has a markedly narrower distal lobe. The female genitalia of B. vestigialis sp. n. ( Fig. 23 ) differ from B. gibonica ( Fig. 24 ) and B. nebulifera ( Fig. 25 ) in the markedly broader posterior sclerotised section of the corpus bursae, and the broader anterior globular section of the corpus bursae. In addition, the signa bursae of the new species are larger than in B. nebulifera .

Description. External morphology of adults. Sexual dimorphism substantial. Male ( Figs 1, 2 ). Forewing length 9.5–10.0mm. Head pale ochreous. Antenna brown, setose. Prothorax and patagia ochreous-yellow. Tegula ochreous-yellow with broad brown spot distally. Mesothorax brown. Metathorax brown with pale ochreous spot medially. Forewing elongate and narrow, with almost parallel margins medially, with rounded apex. Forewing ground colour uniform pale ochreous with bean-shaped greyish-brown diffuse distal shade not reaching wing margins. Hindwing uniform pale ochreous-yellow. Abdomen pale ochreous proximally and ochreous-yellow distally. Male genitalia ( Fig. 17 ). Uncus short, thick, with tapered and downcurved distal half and tiny claw-like tip. Arms of tegumen broad and short. Tuba analis width somewhat less than tegumen length. Scaphium setose. Vinculum longer than tegumen, heavily sclerotised, V-shaped and apically rounded. Valva short, broad proximally and strongly tapered distally with elongate, narrowly triangular and somewhat downcurved dorsal lobe. Ventral plate of costa positioned postmedially and bearing narrow semielliptical crest distally reaching base of distal saccular process. Sacculus narrow with heavily sclerotised distal half. Distal saccular process short, thorn-shaped, distally upcurved and apically rounded. Juxta broadly conical, posteriorly rounded and with weakly sclerotised medial and proximal areas. Phallus more or less equal in length to vinculum, broad, with dilated and serrulate distal third. Vesica with broad semiglobular and granulose dorsal chamber bearing robust thorn-like cornutus with strongly dilated base. Medial diverticulum short, utricular, granulose. Ventral diverticulum broad, semiglobular and membranous with utricular and granulose distal lobe and bearing short but basally broad cornutus ventrally. Distal diverticulum strongly elongate and tubular, membranous proximally and medially, granulose distally and bearing short but basally broad cornutus apically. Vesica ejaculatorius originates medially-laterally. Female ( Fig. 3 ). Forewing length 10.5–11.0 mm. Head pale ochreous. Antenna brown, filiform. Prothorax and patagia ochreous-yellow. Tegula ochreous-yellow with broad brown spot distally. Mesothorax brown. Metathorax brown with pale ochreous spot medially. Forewing elongate and narrow, with rounded apex. Forewing ground colour brown with broad pale yellow costal stripe encircling apex, and thin pale yellow terminal line. Cilia pale yellow. Hindwing ground colour uniform pale yellow, more intense distally and along outer margin. Abdomen pale ochreous proximally and brown with ochreous-yellow suffusion distally. Female genitalia ( Fig. 23 ). Papilla analis trapezoid with rounded corners, setose. Apophyses long and thin, apophysis anterioris shorter than apophysis posterioris. Ostium bursae broad. Postvaginal plate short but broad, weakly sclerotised. Ventral and lateral margins of ostium bursae gelatinous and somewhat swollen. Ductus bursae short, dorso-ventrally flattened, heavily sclerotised with longitudinal folds. Posterior section of corpus bursae conical with asymmetrically protruding right margin, heavily sclerotised with gelatinous medial part. Anterior section of corpus bursae broader than posterior one, semiglobular, weakly granulose and bearing two small circular signa. Appendix bursae asymmetrically conical and apically rounded, heavily sclerotised, positioned ventrally-laterally on right side of posterior section of corpus bursae.

Distribution. Endemic to the Andaman Islands.

Etymology. The specific epithet refers to the distal spot of the male forewing, which is markedly smaller than in the similar species.

Figures

Figures 1–10. Brunia spp.: adults. Depositories of the specimens: 1–3, and 5–9 in MWM/ZSM; 4 and 10 in NHMUK (©The Trustees of NHMUK).

Figures 17–19. Brunia spp.: male genitalia. The specimens dissected are deposited in MWM/ZSM.

Figures 23–27. Brunia spp.: female genitalia. The specimens dissected are deposited in MWM/ZSM.

Figures 11–16. Brunia spp.: adults. Depositories of the specimens: 11 in NHMUK (©The Trustees of NHMUK); 12–16 in MWM/ZSM.