Hydraena (Monomadraena) bisinuloba, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 30-31

Hydraena (Monomadraena) bisinuloba species group

Three species are included in this group: H. bisinuloba , H. bispica , and H. quatriloba . Members of this group are of moderate size (ca. 1.69–1.97 mm), dark brown, with the margins of the pronotum slightly lighter. The dorsal punctation is coarse and dense. The anteromedian carina of the metaventrite is almost absent, represented by a very low elevation or line of granules. The posterior ridge of the genae is absent or very low. The prosternal intercoxal process (P1) is laminate, much narrower that P2, which is parallel sided. All three species have similar plaques, which are very narrow, non-carinate lines that are convergent anteriorly and widely separated posteriorly. Mesotibiae of males are slender and straight, and do not have a row of prominent sharp spines.

Based on external and aedeagal morphology the three species are closely related. The aedeagi have a similar general plan: the main piece is wide in both ventral and lateral aspects, and has a large process on the ventral surface; the distal piece is large and lobate, and the gonopore is located at the end of a short duct that does not extend above the distal piece. The single paramere (right side) is slender, originates near the basal orifice, and does not extend beyond the process of the main piece.