Bolboceras orissicum, Krikken, Jan, 2013

Krikken, Jan, 2013, Distinguishing Bolboceras inaequale Westwood, 1848 and two new relatives from India (Coleoptera, Geotrupidae, Bolboceratinae), ZooKeys 276, pp. 55-66 : 62-64

Bolboceras orissicum sp. n. Figures 7-812, 1422-23

Material examined.

Holotype male (MNHN, ex Boucomont coll.) from India: [Orissa:] Ganjam: Surada [also spelled Sorada], H. Donckier. Male and female paratypes (SMF) from [India: Jharkhand:] "Burju \ Bengal".

Diagnosis.

Saddle separating discomedian and discolateral concavities on pronotum very short, broad, not lowered in relation to surrounding discal surface, discoparamedian tubercles distinctly separated by anterior part of discomedian concavity between them; discolateral concavity quasi-extending onto shallowly concave anterolateral corner; posterior edge of discolateral concavity well defined, “swollen” near saddle with discomedian concavity (outline in dorsal view sinuate). Posterior edge of discomedian concavity virtually rounded. Interocular transverse ridge situated between posterior part of eyes, low, not reaching paraocular ridge on either side. Anterolateral corners of clypeus strongly protuberant (intervening ridge concave in axial view). Scutellum usually abundantly punctate. Aedeagus with narrow, acuminate parameres, median apparatus with pair of strongly sclerotized lateral stalks, their tip very broadly recurved-hooked. Colour uniformly light-brown. Body length roughly 12.5-13.5 mm.

Description

(holotype, male). Body length ca 13 mm. Colour uniformly light-brown, shiny, certain parts sericeous.

Labrum with emarginate anteromedian border, transverse ridge on rugulate upper surface fine, distinct. Clypeal surface with supra-anterolateral angles distinctly raised, dentate, intervening ridge concave in axial view, straight in full-face view; lateral perimarginal ridges distinct, strongly evenly curved, genal angle distinct. Clypeus densely punctate, remainder of head surface abundantly, evenly, distinctly punctate, primary punctures interspersed with fine secondary punctation being denser behind interocular ridge. Anterior edge of eye canthus raised to slight anterolateral angle, thence arcuate along edge of distal lobe; surface coarsely rugulate; paraocular ridge distinct, fine issuing from genal angle, virtually straight, extending posteriorly along eye. Transverse interocular elevation between posterior part of eyes, long, low, not reaching paraocular ridges, lateral slope slight, crest fine, unmodified, lateral angle obtuse on either end (axial view). Much of head surface subsericeous.

Pronotum anteromedially steeply declivous, outline of marginate (raised) anterior border slightly convex (dorsal view); discoparamedian and discolateral protrusions on pronotum distinctly protuberant, subrectangular (lateral view), their tip rounded; discomedian concavity very distinct, evenly concave, broad, anterior part situated between discoparamedian tubercles (not continuing over anterior declivity), posterior edge broadly rounded (dorsal view); discolateral concavity deep, posterior edge sinuate; anteriorly, at bottom, delimited by crowdedly, coarsely punctate patch behind eyes; saddle from discoparamedian tubercle to posterior disc very short, not lowered; bottom of discal concavities and anterior declivity subsericeous; basomedian surface glossy, with abundantly, finely punctate midline impression; anterolateral angle of marginal pronotal ridge ca 100˚ (full-face view). Pronotal surface with double punctation, primary punctation (size variable) laterally generally abundant, denser on anterior declivity; secondary punctation sparse, minute. Pronotal base broadly marginate, lined with numerous punctures. Scutellum with abundant, double punctation.

Intercoxal anterior lobe of metasternum simply truncate in front.

Elytra with discal striae shallowly impressed, finely punctate; punctures separated by 2-3 puncture diameters, slightly crenulating interstriae. Elytral interstriae (on cross-section) very slightly convex, vaguely, sparsely, micropunctate.

Protibia with 6 external denticles; apex unmodified, with robust, complanate, slightly tapering spur. Outer side of meso- and metatibiae with bilobate apical and one complete anteapical fossorial elevation (their crest fringed with fine spines).

Aedeagus, Fig. 14; sclerotized lateral stalks broad with recurved, hooked tip, parameral sheaths narrow, acuminate.

Measurements of body parts. Median length of head (full-face, excluding labrum and mandibles) 2.6 mm, width (including eyes) 4.2 mm. Median length of pronotum (dorsal) 4.6 mm, maximum width 8.2 mm. Median length of scutellum 1.1 mm, maximum width 1.4 mm. Sutural length of elytra (dorsal) 3.9 mm, maximum width combined 8.3 mm. Width genital capsule 1.35 mm.

Variation.

Variation slight, but beware of possibly deceptive polymorphism (may be obvious in larger series).

Sexual dimorphism.

No obvious sexual dimorphism.

Distribution.

Northeast India, apparently South of the Ganges.

Comment.

The place called Burju, origin of the paratypes, is mentioned in the list of "post-office pincodes" in the Ranchi District of Jharkhand (India), and at the time of the collection of the SMF specimens there was a German mission school in the area, with staff sending specimens to German entomologists (around 1890-1910).

Etymology.

Named after the type region.