Bolboceras arunachalensis Chandra, Gupta & Ghosh, 2020

Gupta, Devanshu, Chandra, Kailash, Ghosh, Joyjit & Das, Priyanka, 2020, A new species and new records of the genus Bolboceras Kirby, 1819 (Coleoptera Scarabaeoidea: Geotrupidae: Bolboceratinae) from India, Zootaxa 4786 (2), pp. 277-282 : 279

Bolboceras arunachalensis Chandra, Gupta & Ghosh , new species

( Figs. 1 – 6 )

Type locality. India, Arunachal Pradesh, Papumpare .

Type material (2 specimens). Holotype, male: “ India, Arunachal Pradesh, Papumpare , 23.x.1996, collected S.K. Mondol ” ( NZSI) . Paratype, male: same data as for holotype ( NZSI) .

Description (holotype, male). Shape subglobular. Dark brown, more or less shiny.

Head ( Fig. 3 ). Labrum anterior margin concave-shaped, apical ridge bisinuated. Lateral ridges of clypeus convergent to a single anteromedian elevated point, with apex broadly rounded; perimarginal disc distinct and K-shaped. Clypeus closely punctured; frons smooth with few punctures; surface before interocular ridge nearly smooth; genal angle rounded. Anterior edge of eye canthus short, with a small indistinct anterolateral tubercle, thence arcuate at tip, surface rugo-punctate. Paraocular ridge fine, rounded, extended posteriorly beyond side of interocular elevation. Transverse interocular ridge long and straight, not reaching paraocular ridges.

Pronotum ( Fig. 4 ). Anteromedially very slightly depressed (laterally), with large punctures; discoparamedian and lateral tubercles absent; pronotum elevated medially forming an inverted W-shaped carina; discomedian surface smooth, with punctured median groove, discolateral protrusion absent; basal margin of pronotum punctured; anterolateral point blunt; pronotum punctures vary from large to small, with large punctures arranged at anterior and lateral pronotal fovea and disco lateral protrusion, few punctures between lateral fovea and basomedian part.

Scutellum ( Fig. 5 ). Finely punctured anteriorly.

Elytra ( Fig. 6 ). Discal striae deeply impressed, striae finely punctured; stria 2 incomplete before reaching up to base; intervals convex and smooth; lateral part of elytron finely smooth.

Legs. Protibia hexadentate, denticles reduce in size from apex to end; terminal spur sharp and slender; apex of mesotibiae and metatibiae bilobed, their crest fringed with spines.

Aedeagus ( Fig. 2 ). Parameres acuminate, slightly curved outwardly, tips pointed, sclerotized aedeagal stalks expanded downward, tips of stalks blunt, paramedian aedeagal struts thick, median aedeagal apparatus rounded at apex.

Measurements: Body length: 11.52 mm, width: 7.0 mm. Head, length in dorsal view excluding labrum and mandibles: 2.33 mm; interocular ridge: 1.46 mm; ocular distance: 2.16 mm. Pronotum length: 3.67 mm; width: 6.78 mm. Scutellar shield length: 1.08 mm, width: 1.07 mm. Elytra sutural length: 4.18 mm. Genital capsule width: 0.9 mm.

Etymology. The specific name arunachalensis refers to the place where the new species has been collected, the state of Arunachal Pradesh, India.

Distribution ( Fig. 7 ). So far known only from the type locality, Papumpare, Arunachal Pradesh.

Differential diagnosis. Bolboceras arunachalensis new species is delineated mainly by the unique structure of the aedeagus. The newly described species belongs to B. nigricans group, because of lateral ridges of the clypeus convergent to a single anteromedian elevated point ( Fig. 3 ). Within the B. nigricans group, new species shares K-shaped perimarginal ridges of male clypeus with B. nigricans , B. malabaricum , B. mimicans , B. schulzei , B. bilaspuricans , B. darjeelicans , and B. sahyadriensis . While remaining two species, B. extraneum and B. insulare , bear X-shaped perimarginal ridges.

Morphologically, B. arunachalensis new species is similar to B. malabaricum , B. bilaspuricans , and B. sahyadriensis , and closely related to B. malabaricum . In B. arunachalensis new species, the aedeagal stalks are long and expanded, pronotum with an inverted W-shaped carina medially, and the interocular ridge is long; whereas in B. malabaricum , the aedeagal stalks are small and narrow, pronotum with slightly developed discoparamedian and lateral tubercles, and the interocular ridge is small. In B. arunachalensis new species, the parameral tips are acuminate, but subangular in B. bilaspuricans . Bolboceras sahyadriensis differs from the new species in having comparatively small and narrow aedeagal stalks and pronotum with well-developed discoparamedian and lateral tubercles.

Figures

FIGURE 7. Map of India and Arunachal Pradesh showing type locality of Bolboceras arunachalensis Chandra, Gupta & Ghosh, new species.

FIGURES 1–6. Bolboceras arunachalensis Chandra, Gupta & Ghosh, new species (holotype). 1, habitus, dorsal view; 2, parameres, dorsal (frontal) view; 3, head and clypeus; 4, pronotum; 5, scutellum; 6, elytra.