Canthidium (Neocanthidium), Martinez et al., 1964

Carvalho De Santana, Edrielly C., Pacheco, Thaynara L. & Vaz-De, Fernando Z., 2019, Taxonomic revision of the Canthidium Erichson, 1847 species of the gigas group (Coleoptera, Scarabaeidae, Scarabaeinae), European Journal of Taxonomy 530, pp. 1-24 : 3-4

Subgenus Neocanthidium Martínez et al., 1964

The gigas species group

Diagnosis

Species of the gigas group are readily recognizable from other members of the genus by their large (8 to 15 mm), globose black body, which contrasts with the light-coloured antennae. In addition, the group shows coarse punctation on head and anterior surface of the pronotum; dorsal surface of the eyes posteriorly narrowed; interocular distance approximately seven times wider than the maximum dorsal eye width, and clypeus with two well-defined rounded teeth separated by an acute angle.

Description

Clypeal margin well defined internally, with two more or less rounded teeth medially, separated by an acute angle. Clypeogenal suture distinct. Hypomeron with coarse longitudinal microsculpture between punctuation and obliquely-oriented setae. Prosternum with few long setae, with greater concentration at central region, the apex of each setae reaches mesoventrite. Profemora with ventral surface with a longitudinal carina along posterior margin and with a distinct row of punctures along anterior margin, each puncture with a golden seta; surface with microstriae; tibiofemoral joint with a tuft of golden setae. Protibiae widening towards apex, external edge with three teeth, external edge serrate between proximal tooth and base, dorsal surface with punctation along the central axis, anteriorly with long setae; venter with longitudinal carina and a single row of punctures parallel to lateral edge. Protibial spur tapering towards apex and more or less angulate at apical third in females or wider apically and bent ventrally at median half in males. Tarsi with five tarsomeres; claws simple, strongly curved. Mesofemora with a carina along posterior edge, ventral surface with some setae anteroapically, centre and apex with minute punctation. Mesotibiae with narrow basal half, apical half abruptly dilated, with carina and punctation along anterior margin, near the carina with punctation; external edge with small teeth, internal edge smooth. First mesotarsomere as long as next two mesotarsomeres combined; second to fourth mesotarsomeres decreasing gradually in length and fifth mesotarsomere longer than the fourth; claws simple and strongly curved; two apical spurs, one as long as the first mesotarsomere and the other as long as the first and second mesotarsomeres combined. Elytral striae wide and distinct, with circular punctures slightly wider than the striae. Interstriae with small, scattered punctures. Pseudepipleuron narrowing gradually towards the apex, where it dilates slightly at the end of the fifth striae; surface with sparse fine punctation. Abdomen glabrous, finely punctate. Pygidium convex, margined along posterior edge, distinctly punctate.

Sexual dimorphism

Males and females can be differentiated by the protibial spur, which has a narrow apex in females and is flattened in males.