Bidessodes obscuripennis (Zimmermann, 1921)

Miller, Kelly B., 2017, A review of the Neotropical genus Bidessodes Regimbart, 1895 including description of four new species (Coleoptera, Adephaga, Dytiscidae, Hydroporinae, Bidessini), ZooKeys 658, pp. 9-38 : 29-30

Bidessodes obscuripennis (Zimmermann, 1921) Figs 77-81, 100

Bidessus (Bidessodes) obscuripennis Zimmermann, 1921: 19; Blackwelder 1944: 76.

Bidessodes obscuripennis , Young 1969: 2.

Bidessodes (Hughbosdinius) obscuripennis , Young 1986: 209; Biström 1988: 7; Nilsson 2016: 98.

Diagnosis.

The species differs from others in having the prosternal process anteriorly carinate with distinctive setae in males. Females have the prosternal process unmodified. This species and Bidessodes knischi each have the prosternal process basally carinate, at least in males, but they are otherwise rather different. The prosternal process is narrow, flat, with the lateral margins slightly convergent to the pointed apex. The metaventrite is not transversely grooved. The male mesotibia is unmodified. The metatrochanter in males is exceptionally large, distinctly offset and prominent apically (Fig. 81). The male abdominal ventrite VI is apically broadly impressed. The male genitalia are also distinctive. In lateral aspect the median lobe is slender and apically abruptly curved (Fig. 78). In ventral aspect the median lobe is deeply bifid, each branch ending in a bifurcation. The medial branch of each bifurcation is sinuate and apically pointed, the lateral branch is broad and apically subtruncate (Fig. 79). The lateral lobe has the apical segment extremely broad and irregularly margined (Fig. 80). Specimens are robust with complex maculae on the elytra (Fig. 77).

Distribution.

Known from Guyana and western Brazil (Fig. 100).