Stictobura Crotch, 1874

Vandenberg, Natalia J., 2011, A revision of the genus Stictobura Crotch and description of a new species of Sticholotis Crotch (Coleoptera: Coccinellidae: Sticholotidinae), Zootaxa 3031, pp. 1-13 : 2-3

Stictobura Crotch, 1874

Stictobura Crotch, 1874: 201 ; Sicard, 1911: 385. Type species: Calvia ? pallideguttata Mulsant, 1853 , by monotypy. Apterolotis Weise, 1908: 225; 1923: 127.— Sicard, 1911: 385 (synonymy).— Korschefsky, 1931: 211. Type species: Sticholotis (Apterolotis) andrewesi Weise, 1908 (= Stictobura pallideguttata ( Mulsant, 1853) , by subsequent designation of Korschefsky, 1931.

Diagnosis. Body medium to large, with a round or subcircular outline ( Figs. 1–7 ); dorsum very strongly convex and hemispherical, without apparent vestiture but characterized by sparse, thin, suberect to erect hairs on pronotum and elytra, easily noticeable particularly on anterior, lateral and posterior margins of elytra, those on disc noticeable only at high magnifications. Head ( Fig. 12 ) with clypeal margin always distinctly semi-circularly emarginate. Eyes small, widely separated, coarsely faceted, inner margins with distinct orbital carinae, posteriorly divergent towards temples; ocular canthus extending shortly into eyes. Antennal insertions exposed, frons around antennal insertions distinctly, deeply emarginate. Antenna ( Fig. 13 ) 11-segmented, with a three-segmented, elongate, fusiform club, terminal antennomere apically elongate, conical-oval. Terminal segment of maxillary palpi ( Fig. 15 ) elongate conical, apical margin strongly and obliquely truncate, shorter than outer margin. Pronotum transverse, anterior margin deeply trapezoidally emarginate around head; posterior margin strongly arcuate, with submarginal line; lateral margins linear to broadly rounded, with short scattered hairs, finely carinate, narrowly reflexed. Interspaces between punctures on head and pronotum always with strong reticulate microsculpture. Elytra lacking humeral calli, lateral borders with a distinct marginal bead; punctation on elytra often conspicuously dual, with fine and coarser punctures intermixed. Prosternum T-shaped, anterior margin not lobed in front of coxa, prosternal process ( Fig. 17 ) very broad, quadrate with a pair of carinae. Anterior margin of mesoventrite broadly shallowly emarginate medially. Abdomen with five visible ventrites in both sexes, ventrites 1 and 5 subequal, longer than rest; abdominal postcoxal lines ( Fig. 16 ) incomplete, parallel to or approaching posterior margin of ventrite 1. Functional wings absent. Elytral epipleura broad, complete with inner carina reaching apex of elytra, shallowly foveolate or depressed on level with middle and hind legs. Legs with cryptotetramerous tarsi, tarsal claws swollen basally, lacking a distinct basal tooth. Male genitalia ( Figs. 19–31 ) with phallobase having an additional median strut besides trabes; basal lobe [=“penis guide” sensu Ślipiński (2007), or “median lobe” auctorum] of tegmen elongate, symmetrical, parameres long with several marginal and apical setae; sipho [=“penis” sensu Ślipiński (2007)] stout, with a large, prominent capsule. Female genitalia with coxites elongate triangular, bearing short styli, with a very long bursa and a rather large and moderately sclerotized structure ( Fig. 32 ), representing a poorly differentiated spermatheca, or possibly just a lobe of the bursa.

Distribution. This genus is apparently endemic to the Western Ghats range in southern India. Its members are rarely collected and have been found almost exclusively in plantations at high altitudes.

Related genera. Stictobura is very closely related to Sticholotis . Its species differ from those of the latter only by their distinctly larger size, strongly convex / hemispherical dorsum, strongly reticulate microsculpture on interspaces between punctures on head and pronotum, elytra with a distinct marginal bead, absence of functional wings, and male genitalia with a very stout sipho having a large capsule. Stictobura species have sparse, somewhat inconspicuous, but more or less uniform, fine, suberect to erect pubescence on the pronotum and elytra, though most of the old specimens examined in this study appeared to be glabrous due to abrasion. Many species of Sticholotis appear to be glabrous, but have sparse, very short erect hairs on the elytra. Functional wings are absent in many Australian species of Sticholotis and all the species of Nesolotis Miyatake (1966) . Ślipiński (2004) regarded Nesolotis as a synonym of Sticholotis , but Wang et al. (2010) resurrected the genus based on its distinctly foveate elytral epipleura, tibiae of front legs strongly expanded externally, and other features. Some unusually large species of Sticholotis that resemble Stictobura occur in Vietnam, northeastern India, and Indonesia.

Among other Asian Sticholotidini, Jauravia Motschulsky (1858) shares many features with Stictobura , but has conspicuous dense pubescence all over the body. Filipinolotis Miyatake (1994) appears to be close to Stictobura by virtue of its strongly convex dorsum and atrophied hind wings. Among the Neotropical genera, the Hispaniolan genus Bura Mulsant (1850) has a similar size and body form to Stictobura , but differs in the highly polished appearance of the head and pronotal interspaces, and in possessing fully developed metathoracic wings, 10-segmented antennae, clypeus anteriorly truncate and not emarginate around antennal insertions, and tarsal claws with a large triangular basal tooth ( Vandenberg and Perez-Gelabert, 2007). The composition of Sticholotidini and the taxonomic status of many genera therein have not been fully resolved yet and the ongoing comprehensive studies including molecular studies on the world taxa of Sticholotidinae by other coccinellid workers may throw more light on the interrelationships among these genera. Hence, in spite of its very close relationship with Sticholotis, Stictobura is treated as a distinct genus in this paper.

Biology. Detailed biology is not known for all the species, but prey records from label data indicate a preference for Coccoidea ( Diaspididae ; Coccidae ). Rao et al. (1970) reported a Stictobura sp. as feeding on tea red spider mites. Almost all available specimens in collections have been collected on plantation crops such as tea and coffee.

Figures

FIGURES 1 – 11. Stictobura spp.: 1. Stictobura pallideguttata (Mulsant); 2 – 6. S. semipolita Sicard; 7. S. melanaria (Weise); 8 – 10. Sticholotis gibbula Weise: 8. Dorsal view; 9. Frontal view; 10. Lateral view; 11. Sticholotis buruensis (Korschefsky): Frontal view.

FIGURES 12 – 17. Diagnostic characters of Stictobura: 12. Head; 13. Antenna; 14. Labium; 15. Maxilla; 16. Postcoxal line; 17. Prosternal process. 18 a – e. Stictobura semipolita, elytral pattern variations.

FIGURES 19 – 32. Male genitalia of Stictobura spp.: 19 – 23. S. pallideguttata: 19. Tegmen, lateral view; 20. Tegmen, ventral view; 21. Sipho; 22, 23. Siphonal apex; 24 – 27. Stictobura semipolita: 24. Tegmen, lateral view; 25. Tegmen, ventral view; 26. Sipho; 27. Siphonal apex; 28 – 32. Stictobura melanaria: 28. Tegmen, lateral view; 29. Tegmen, ventral view; 30. Sipho; 31. Siphonal apex; 32. Female genitalia (part): enlarged bursa.