Incomptodessus Miller and Garcia

Miller, Kelly B. & Garcia, Mauricio, 2011, Spanglerodessus shorti and Incomptodessus camachoi, new genera and species of Bidessini from Guyana and Venezuela (Coleoptera: Dytiscidae: Hydroporinae), Zootaxa 2996, pp. 49-56 : 53

Incomptodessus Miller and Garcia , new genus

( Figs. 7 –10,12–14)

Type species. Incomptodessus camachoi Miller and Garcia , new species, by present designation.

Diagnosis and description. This genus differs from others in the tribe by the combination of: 1) transverse occipital line present ( Fig. 7 ), 2) basal pronotal striae present ( Fig. 7 ), 3) basal elytral stria absent ( Fig. 7 ), 4) elytral sutural stria absent ( Fig. 7 ), 5) anterior clypeal margin unmodified, 6) elytron without longitudinal carinae ( Fig. 7 ), 7) epipleuron without transverse carina at humeral angle, 8) lateral lobes of aedeagus two-segmented ( Fig. 8 ), 9) habitus elongate oval, lateral margin slightly discontinuous between pronotum and elytron ( Fig. 7 ), 10) lateral bead on pronotum narrow ( Fig. 7 ), and 11) metaventrite and metacoxae impunctate.

Etymology. The genus name is formed from a combination of Latin incomptus, meaning “unadorned” because of the simple morphology of members of this genus, and “ dessus,” a common root in other genus names in this tribe.

Distribution and habitat. The single species in the genus is known only from a few localities in the upper Orinoco basin of Venezuela near the town of Puerto Ayacucho where it is hygropetric ( Figs 12–14 ).

Discussion. This genus keys to the South African genus Sharphydrus Omer-Cooper in Biström’s (1988) key to the Bidessini genera of the world. Both Incomptodessus and Sharphydrus have a transverse occipital line on the posterior surface of the head and basal pronotal striae and each lack sutural striae on the elytra, an epipleural carina, keels on the elytra, a border or other modification to the anterior margin of the clypeus, and basal striae on the elytra, among other things. Incomptodessus differs from Sharphydrus in the entirely impunctate metacoxae and metaventrite ( Sharphydrus has a line of punctures on each side of the metaventrite). Incomptodessus is similar also to Tyndallhydrus Sharp , but differs from that genus in having impunctate metacoxae and metaventrite and the prosternal process reaching the mesoventrite. Incomptodessus is similar to both Liodessus Guignot and Neobidessus Young , but differs from both in lacking basal striae on the elytra and from the latter in the lack of an accessory basal stria on the elytra. Two species of Liodessus , L. hobbsi , and L. flavicollis , have reduced basal elytral striae, but the striae, though short, are still present and these species are densely punctate on the dorsal and ventral surfaces and have a rather different body form and other structures from Incomptodessus . Finally, Incomptodessus is similar to Fontidessus Miller and Spangler in many respects, but differs from that genus in the presence of a cervical line (though see Balke and Ribera (2004) for a discussion of this problematic character).

Figures

FIGURES 1 – 9. Figs 1 – 6. Spanglerodessus shorti. 1, dorsal habitus, bar = 1.0 mm. 2, prosternal process. 3, right metathoracic leg, ventral aspect. 4 – 6, male genitalia, 4, median lobe and right lateral lobe, dorsal aspect, 5, median lobe, left lateral aspect, 6, left lateral lobe, left lateral aspect. Figs 7 – 9. Incomptodessus camachoi. 7, dorsal habitus, bar = 1.0 mm. 8, male median lobe and right lateral lobe, right lateral aspect. 9, male median lobe, ventral aspect.

FIGURES 11 – 14. Habitats. 11, Spanglerodessus shorti, AS- 08 - 058. 12 – 14, Incomptodessus comachoi; 12, VZ 09 - 0114 - 01 C; 13, VZ 09 - 0112 - 01 B; 14, VZ 09 - 0115 - 01 D. Codes correspond to collection locality codes listed in “ Material examined ” section for each species.