Bolbochromus nomurai Li & Krikken

Li, Chun-Lin, Yang, Ping-Shih, Krikken, Jan & Wang, Chuan-Chan, 2013, Three new species of Bolbochromus Boucomont (Coleoptera, Geotrupidae, Bolboceratinae) from Southeast Asia, ZooKeys 290, pp. 39-54 : 46-48

Bolbochromus nomurai Li & Krikken sp. n. Figs 26, 815-1620

Holotype

male. The holotype is glued to a paper point and labeled: VIETNAM: Deo Pha Din (1000-1400m), Son La Prov.// [N. VIETNAM]// 24. VI. 1997// S. Nomura leg. (deposited at the National Museum of Nature and Science, Tokyo, Japan).

Type locality.

Northern Vietnam: Son La Province, Deo Pha Din, 21°70'N, 103°50'E (Fig. 23).

Description.

Holotype male (Fig. 2, 6, 8). Body length 7.1 mm; greatest width 4.1 mm. Form elongate-subovate, sides parallel. Dorsum black, with margins of head, pronotum, and elytron reddish black; isolated brownish orange markings located on each corner of pronotum, shape irregular, subequal in size (Fig. 8); elytral markings across base of striae 1-6 and interval 7, shape transversely rounded (Fig. 2). Head:Labrum with anterior margin feebly triangularly concave centrally, sides notched. Clypeal apex subtrapezoidal (Fig. 6), anterior margin beaded with a small, weakly-developed convexity at middle, surface smooth, coarsely punctate in uneven distribution, confluent or separated by less than 1 puncture diameter. Clypeofrontal suture absent. Vertex with inconspicuous conical convexity at middle of base with apex rounded, punctures on surface shallower and sparser than those on clypeus. Thorax: Outline of pronotum rounded, surface coarsely punctate along side of disc, less dense toward mid-disc; midline moderately indented with shallow and inconspicuous punctures; both sides of midline and area in front of elytral base impunctate with five smaller punctures at anterior end of midline (Fig. 6); disc gradually declined anteriorly when viewed laterally (Fig. 8). Metasternal process poorly developed, narrowly separating middle coxae with anterior margin beaded. Scutellum with scattered secondary punctures, slightly longer than wide medially. Elytron:With 7 striae between suture and humeral umbone, stria 2 interrupted by stria 1 not reaching base, stria 5 terminating at basal one-ninth; interval 4 more convex and wider than others at basal one-fifth, interval 2, 5, and 6 less convex than others (Figs 2, 8). Legs: Protibia with 10 distinct teeth on outer margin, apical 3 teeth protruding, tip of apical tooth downcurved. Male genitalia: Length 1.9 mm. Parameres (Figs 15-16) elongate, dorsal surface concave at basal half when viewed laterally, dorsal margin slightly declined at apical one-third anteriorly (Fig. 20), well sclerotized laterally with medial and apical parts membranous, surface sparsely punctate, glabrous; subequal in length to basal piece. Median lobe (Figs 15-16) trilobate; dorsal sclerite thumb-like with apex slightly swelling; lateral sclerites shorter than dorsal sclerite, broadly crescent-shaped, inwardly curved slightly with tip sharp and highly sclerotized; supporting sclerites L-shaped with central part more sclerotized than lateral side. Internal sac embedded in median lobe. Temones moderately sclerotized, thin and elongate to apical one-third of basal piece (Fig. 15). Basal piece with apical part asymmetrical.

Female. Unknown.

Etymology.

Bolbochromus nomurai is named after Dr. Shûhei Nomura of the National Museum of Nature and Science, Tokyo, who has always assisted C.-L. Li’s visits to the scarab collections of the museum.

Diagnosis.

Bolbochromus nomurai is similar to Bolbochromus plagiatus , but it can be distinguished based on the following combination of characteristics: larger in body size (smaller in Bolbochromus plagiatus ); clypeal apex subtrapezoidal (rounded in Bolbochromus plagiatus ); anterior margin of clypeus with a small, weakly-developed convexity at middle; (anterior margin simply beaded in Bolbochromus plagiatus ); vertex with an inconspicuous conical convexity at middle of base (weakly convex in Bolbochromus plagiatus ); outline of pronotum rounded (transverse in Bolbochromus plagiatus ); punctures of pronotal midline shallow and inconspicuous (coarsely rugopunctate in Bolbochromus plagiatus ); pronotal markings separated on each corner (connected in Bolbochromus plagiatus ); elytral markings across base of striae 1-6 and interval 7 (across from stria 1 to epipleuron in Bolbochromus plagiatus ).

Remarks.

Boucomont and Gillet (1921) and Paulian (1945) listed and diagnosed two Bolbochromus species ( Bolbochromus laetus and Bolbochromus plagiatus ) from Vietnam and neighboring areas which were originally recorded from Sri Lanka and northern India. Yet, we were not able to access the material studied by Paulian, and so we cannot be sure of the identity of specimens that he used. Considering the similarity of Bolbochromus plagiatus to Bolbochromus nomurai and other species occurring in Indochina, it is reasonable to assume that the identifications of Paulian are incorrect as it is unlikely he compared their male genitalia. To solve this problem it is necessary to re-examine the relevant specimens.