Bolboceras sahyadriensis Kalawate & Hillert, 2018

Kalawate, Aparna & Hillert, Oliver, 2018, A new species and new records of the genus Bolboceras Kirby, 1819 (Coleoptera: Geotrupidae: Bolboceratinae) from India, Zootaxa 4457 (4), pp. 595-599 : 595-598

Bolboceras sahyadriensis Kalawate & Hillert , new species ( Figs. 2A–H )

Type locality. Bhosgaon , Satara District, Maharashtra, India [17.229°N, 73.952°E, 731 m].

Type material. Holotype, male, labeled: “ India, Forest Rest House, near Bhosgaon, Patan taluk, Satara district , Maharashtra (17.229°N, 73.952°E; altitude 731 m), 15 July 2017, Aparna Kalawate lgt.” (deposited in ZSI-WRC, catalogue number ENT-1/2916) ; paratype male, same data as holotype (deposited in ZSI-WRC, catalogue number ENT- 1/2952).

Description of holotype male. Body distinctly convex, surface brown, elytra light brown and shiny; pronotum microsculptured basally, punctation distinct but sparse in anterior half; elytron microsculptured ( Figs. 2A–B ).

Head ( Fig. 2C ). Labrum with slightly concave anterior margin; transverse ridge indistinct; lateral perimarginal ridge

of clypeus convergent to a single, anteromedian, weakly transverse tubercle. Perimarginal clypeal ridge distinct, kshaped; frons densely punctate; vertex distinctly but sparsely punctate; transversal interocular ridge straight, long (approximately 0.75 times of interocular distance), non-tuberculate, not reaching paraocular ridges, occupying approximately basal third of eyes, lateral slope distinct, crest equally developed. Surface behind transverse interocular ridge smooth with few irregular punctures; anterior edge of eye canthus regularly convex, surface rugopunctate, with distinctly pointed tubercle; paraocular ridge fine, almost straight, reaching beyond level of interocular elevation, but not reaching base of head.

Pronotum ( Fig. 2D ). Slightly depressed anteromedially in lateral view; discoparamedian protrusions conically pointed; discolateral protrusions distinctly elevated; discomedian impressions distinct, deeply impressed, posteriorly evenly rounded; discolateral impressions distinct, shallow, rounded; finely punctate midline impression at basomedian surface. Base of pronotum finely micropunctate; pronotal punctures are of two types; first type of punctures larger, abundant laterally, anteriorly, and along margins, a clusters of 20–25 distinct punctures formed from edge of lateral (punctate) fovea on basomedian surface; second type of punctures are sparse and small; margin of base of pronotum distinct.

Scutellum ( Fig. 2E ). Triangulate, sparsely punctate.

Elytra ( Fig. 2F ). With weakly impressed, finely punctate striae; intervals smooth.

Legs. Protibia with 6 distinct external denticles, diminishing in size from apex to base; apex of terminal spur robust, tapering and sharp apically. Mesotibiae and metatibiae with distinctly elevated, transverse carina.

Aedeagus ( Figs. 2G–H ). Parameres thin, strongly acuminate, divergent laterally, overlapped in basal part of aedeagus, reaching beyond paramedian aedeagal struts. Lateral aedeagal stalks robust, strongly sclerotized, finely hooked, recurved at apex; median aedeagal apparatus (upper lobe) plain, rounded anteriorly.

Measurements. Body length: 12.3 mm, width: 7.6 mm. Head, length in dorsal view excluding labrum and mandibles: 2.2 mm, width: 3.7 mm; interocular ridge: 1.8 mm; ocular distance: 2.6 mm. Pronotum length: 4.5 mm, width: 7.4 mm. Scutellar shield length: 1.4 mm, width: 1.5 mm. Elytra, sutural length: 4.0 mm, maximum width combined: 7.8 mm. Genital capsule width 0.9 mm.

Etymology. This species is named after “Sahyadri”, the Sanskrit and Marathi name for the Western Ghats where it occurs.

Distribution. Known only from the type locality: Bhosgaon, Satara District (Western Ghats), Maharashtra, India.

Differential diagnosis and remarks. The species of the B. nigricans species group are separated on the basis of characteristic perimarginal clypeal ridges. The clypeal ridges in males are convergent to a single anteromedian tubercle. The clypeal ridges are k-shaped or x-shaped in dorsal view. According to Krikken (2013a), the species in B. nigricans species group can be separated by characteristic x-shaped clypeal ridge ( B. extraneum Krikken, 2013 and B. insulare Krikken, 2013 ) and k-shaped clypeal ridge ( B. nigricans Westwood, 1848 , B. malabaricum Krikken, 2013 , B. mimicans Krikken, 2013 , B. schulzei Krikken, 2013 , B. bilaspuricans Gupta & Chandra, 2016 and B. darjeelicans Gupta & Chandra, 2016 ). The discomedian and discolateral impressions of pronotum are more or less deeply impressed (see Krikken 2013a). The pronotal impressions probably depend on body size. The allometric specimens show often only weakly developed characters.

Among the species of B. nigricans species group, B. sahyadriensis is unique mainly due to its structure of aedeagus. The new species has a thin, strongly acuminate, and laterally divergent parameres that overlap the basal part of the aedeagus. The parameres extend beyond the paramedian aedeagal struts. The lateral aedeagal stalks are robust, strongly sclerotized, finely hooked, and recurved at the apex. The median aedeagal apparatus (upper lobe) is plain anteriorly. The basal genitalic capsule is broad. The closely related species, B. bilaspuricans and B. malabaricum have a similar structure of the aedeagus. The new species is, however, differentiated from them by the presence of strongly acuminate paramere tip that extends beyond the paramedian aedeagal struts; basal genitalic capsule broad. In B. bilaspuricans the tip of parameres are subangular, reaching just beyond the lateral aedeagal stalks, basal genitalic capsule not broad; whereas, in B. malabaricum , the parameres are acuminate and extended to the lateral aedeagal stalks; the basal genitalic capsule smaller. Bolboceras sahyadriensis is morphologically distinct from its close relatives by the presence of the long and non-tuberculate transverse interocular ridge, the evenly developed crest, the greater height of the interocular ridge; the slightly concave anterior margin of the labrum, and the indistinct transverse ridge. Conversely, the transverse interocular ridge of B. malabaricum is very short and tuberculate (medially raised), unevenly crested, height of the interocular ridge high; the labrum has a slightly concave anterior margin and the transverse ridge is distinct. The transverse interocular ridge of B. bilaspuricans is long and non-tuberculate, evenly crested, height of the interocular ridge is low; the labrum with slightly concave anterior margin and the transverse ridge is distinct. For differentiation of B. sahyadriensis from B. malabaricum and B. bilaspuricans see Table 1.

Figures

FIGURE 2. Holotype of Bolboceras sahyadriensis Kalawate & Hillert, new species. A, dorsal habitus; B, lateral habitus; C, head, dorsal view; D, pronotum, dorsal view; E, scutellum; F, elytron; G, H, aedeagus. Scale bars = 2 mm (A–D, F); 1 mm (E); 0.5 mm (G, H).