Hydrobiomorpha iguazu Bachmann, 1988

Figs 1 C, 2 C, 3 C, 4 E, 4 F, 5 I – L

Hydrobiomorpha iguazu: Contartese and Bachmann 1987: fig. 3 (nomen nudum, distribution only).

Hydrobiomorpha iguazu Bachmann, 1988: 9, 15–16, fig. 31 A – H (original description; key to species of the Americas).

Hydrobiomorpha iguazu: Bachmann et al. 2002: 141 (female description).

Type locality.

Argentina: Misiones Province, Parque Nacional Iguazú [25 ° 31 ' 05 " S, 54 ° 08 ' 00 " W].

Material examined.

Argentina: • Misiones Province: Iguazú National Park [25 ° 31 ' 05 " S, 54 ° 08 ' 00 " W], x. 1980, 1 ♂ (holotype, MACN - En 2213); • same locality iv. 2001, PLM Torres and MC Michat leg., 1 ♀ (MACN - En).

Diagnosis.

L: 22.6 mm (male holotype), 21.0 mm (female). W: 10.6 mm (both sexes). Body shape (Figs 1 C, 2 C, 3 C): subelliptical, slightly convex; elytral margin moderately reflexed on the posterior 2 / 3. Prosternal keel (Fig. 3 C): moderately long, ventral margin nearly straight; posterior spine very short. Metaventral keel (Fig. 3 C): slightly broadened, ending posteriorly in a short, laterally compressed, blunt tip, reaching approximately mid-length of first abdominal ventrite. Male: mesotibial setigerous furrow present, short, extending for ~ 1 / 4 of tibial length, with a short reddish setal brush (Table 1); fifth abdominal ventrite with a very large, subquadrate glabrous area, ~ 3 / 4 of its total length (Fig. 4 E); protarsal claws unknown, not preserved in holotype (only known male); mesotarsal claws robust, with conspicuous proximal tooth; metatarsal claws robust, with conspicuous proximal tooth; genitalia: strongly sclerotized, median lobe subparallel, abruptly narrowed distally, apex bifurcate into two short sharp projections; accessory appendages of median lobe elongate, strongly sclerotized, with acute distal ends; parameres shorter than median lobe, broad in lateral view, narrowed distally and ending in projections, slightly curved towards midline (Fig. 5 I – L). Female: fifth abdominal ventrite with a very large subtriangular glabrous area, ~ 2 / 3 of its total length (Fig. 4 F).

Distribution.

Argentina: Misiones Province (Bachmann 1988; Bachmann et al. 2002).

Biology.

The female was collected from a shallow pond of turbid water (~ 20 cm deep), near the entrance to the Macuco Trail in Iguazú National Park. No habitat data are available for the holotype.

Remarks.

The large size, 21.0– 22.6 mm and dark dorsal coloration resemble those of H. utinga Bachmann, 1988, H. mucajai Bachmann, 1988, H. solitaria Bachmann, 1988, and H. praesumptapolita Bachmann, 1988. The median lobe of the male genitalia resembles that of H. praesumptapolita (Bachmann, 1988). The large bare area on the last abdominal ventrite, and the short setigerous furrow, of 1 / 4 the length of the mesotibiae of males, are distinctive; the above mentioned species have the furrow longer, half as long as the tibiae, and in H. mucajai it is absent.