Hydraena (Monomadraena) tibiodentipes Perkins 2017

Hydraena (Monomadraena) tibiodentipes species group

Fourteen species are included in this group: H. tibiodentipes, H. bisinuata, H. contracolorata, H. amplipunctata, H. parvispinosa, H. triaequalis, H. rubrifurcata H. inseriata, H. levifurcata, H. compacta, H. upsilonica, H. tripartita, H. jubata, and H. sculponea.

Members of this group are of moderate size (ca. 1.48–2.21 mm), usually dark brown or reddish brown dorsally, infrequently with a pronotal macula, and have coarse and dense dorsal punctation. The genae have a strong posterior ridge. The metaventrite has a strong anteromedian carina that is, in ten of the species, contiguous with the plaques, together forming an inverted Y-shape (e.g., Fig. 74). The metaventrite ridges extending from the mesocoxal cavities are also quite strong. The intercoxal processes are relatively wide, with P1 and P2 approximately equal in width. Mesotibiae of males have a row of spines on the inner margin, quite prominent in all but one species, number varying from 2–3 to 4–5, and the margin is usually notched between the spines (e.g., Fig. 57; in H. parvispinosa the spines are very short, and the margin is not notched.

The aedeagi have a similar general plan: the main piece is slender in profile, the single paramere (right side) is large in dorsal aspect, originates near the basal orifice, and extends to or slightly beyond the main piece. In all but one species the gonopore is located at the end of a moderately long to very long, usually coiled, flagellum (e.g., Figs. 67, 68). The aedeagus of H. jubata does not appear to have a flagellum, but only one male is known; it is possible that the flagellum is broken off; the aedeagus is also unusual in the size and shape of the distal piece. Consequently H. jubata is only tentatively placed in this species group.