Bidessodes knischi (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

Bidessodes knischi (Zimmermann, 1921) Figs 67-71, 104

Bidessus (Bidessodes) knischi Zimmermann, 1921: 198; Blackwelder, 1944: 76.

Bidessodes knischi , Young, 1969: 2; 1986: 209.

Hughbosdinius leechi Spangler, 1981: 67; synonymy by Young 1986: 206.

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

Diagnosis.

This species differs from all other species in having the base of the prosternal process distinctly carinate to tectiform in both sexes. In males the ridge anteriorly is flattened and distinctly setose with those setae anteriorly distinctly forked. This species and Bidessodes obscuripennis each have the prosternal process basally carinate, at least in males, but they are otherwise rather different. In Bidessodes obscuripennis , only males are carinate. The prosternal process is flat and broad, the lateral margins are slightly convergent to the broadly rounded apex. Males of Bidessodes knischi have the metaventrite with a prominent transverse groove. The male mesotibia is unmodified. The male metafemur is very broad and rounded (Fig. 71). The male abdominal ventrite VI is distinctly impressed apically. The male genitalia are distinctive. The median lobe in ventral aspect is apically bifid with each branch obliquely bifurcated (Fig. 69). In lateral aspect the median lobe is broadly curved and apically sharply pointed with a distinct expansion along the ventral margin corresponding with the lateral branch of each bifurcation (Fig. 68). The lateral lobe is extremely broad with the apical segment very large and broadly triangular (Fig. 70). Specimens are large and robust with maculate elytra (Fig. 67).

Distribution.

The types were collected from Mato Grosso, Brazil with other specimens collected from lowland areas of South America from Venezuela and Guyana south to Bolivia (Fig. 104).