Bolbochromus Boucomont, 1909

Krikken, Jan & Li, Chun-Lin, 2013, Taxonomy of the Oriental genus Bolbochromus: a generic overview and descriptions of four new species (Coleoptera: Geotrupidae: Bolboceratinae), Zootaxa 3731 (4), pp. 495-519 : 502-506

Subgenus Bolbochromus Boucomont, 1909

Diagnosis. Frontovertex medially at most with limited elevation (usually more or less conical, in some species slightly transverse, (median) tip or crest may be bifid, occasionally only pair of small approximated denticles or median swelling present). Clypeus lacking distinct, long projections (apex may be slightly protuberant, more or less angular, in axial view). Male genitalia diverse, but always with distinct parameres (variably sclerotised, enclosing variably distinct median lobe). Pronotum of the southeast Asian species at most with set of weak antediscal protrusions, in some with blunt transverse ridge topping deplanate-depressed anterior declivity (as in type species); pronotum of several species with distinct (punctate) median sulcus. Elytra with 5 or 7 striae between suture and humeral umbone, convexity of interstriae different according to species.

Type species. Bolboceras laetus Westwood, 1852 ; by subsequent designation—Paulian 1945 (contra Li et al. 2008).

Comments. The type species is characterised by a modified (transversely ridged-tuberculate) anterior side of the pronotum, not thus seen in other described members of the subgenus as here conceived; the tubercle on the head is standing almost on the clypeofrontal transition. The whereabouts of Westwood’s type from “ Ceylon ” has not been established (not seen in BMNH or OUMNH)—it probably concerned a single specimen. Similar specimens, however, were reported from parts of continental Asia as far away from Sri Lanka as Indochina (Boucomont & Gillet 1921, Paulian 1945), and indeed we have seen them from Indochina to west Thailand (male from Laos pictured in this paper, Figs. 23–24 , 44, 47–49). In other words, formally the nomenclature and delimitation of Bolbochromus (i.e., the real identity behind the name Bolboceras laetus sensu Boucomont 1909 ) still has to be settled. The four new species described below are not closely related to Bolbochromus laetus (Westwood, 1852) as described and illustrated by its author. As indicated above, the aedeagal structure of the respective species in this subgenus appears very diverse, and homologies have to be settled.

Subgeneric distribution. Oriental, widespread, roughly as indicated above, for the genus.

Figures

FIGURES 17 – 24. Habitus of male Bolbochromus (oblique and lateral views). 17 – 18, B. sulcicollis; 19 – 20, B. ludekingi; 21 – 22, B. walshi; 23 – 24, B. laetus or near. Scale lines 1 mm.