Obrieniolus del Rio

del Rio, M. Guadalupe & Lanteri, Analia A., 2010, Obrieniolus, a new monotypic genus of Naupactini (Coleoptera, Curculionidae, Entiminae) from the Peruvian Andes and its phylogenetic placement, ZooKeys 102, pp. 51-63 : 52-53

Obrieniolus del Rio gen. n.

Type species.

New species Obrieniolus robustus del Río.

Diagnostic description.

Body rounded and medium-sized; integument black, denuded and shiny, with imbricate microsculpture and reddish-brown tarsi (Figs 1-2); rostrum very short with narrow epistome (Fig. 3); maxillae with suboval mala, not excavate, almost parallel to longitudinal axis of palpus (Fig. 7); prementum subcordate without setae (Figs 4-6); posterior margin of pronotum constricted and slightly posteriorly “V” shaped; elytra cordiform, moderately convex, with slightly posteriorly curved base and slightly prominent and subquadrate humeri (Fig. 1); punctures of striae strongly separated from each other; scutellum tiny, denuded; front coxae slightly separated from each other, 3 × closer to anterior than to posterior margin of prosternum; row of denticles only present in front tibiae; outer bevels of hind tibiae broad and oblique. Ovipositor thin and curved in lateral view, longer than abdomen (Fig. 11); sternite VIII with subrhomboidal elongate plate and apodeme ca. 2 × longer than plate (Fig. 10); spermathecal duct very long, membranous and sinuous (Fig. 13).

Etymology.

The genus is named after the outstanding weevil specialist Charles W. O´Brien, who loaned us the material for this study.

Remarks.

Obrieniolus is distinguished by the particular shape of the body (cordiform, extremely rounded and short), completely covered with imbricate microsculpture, the strongly separated punctures of the elytral striae, and the bursa copulatrix studded with dense and minute spines directed backwards, near the vagina. Other generic characters are common in most Naupactini inhabiting mountain environments, e.g. the black, denuded and strongly sclerotized integument, the absence of metathoracic wings and the reduced shoulders.

Natural history.

Obrieniolus seems to be endemic to northeastern Peru, Department of La Libertad, at about 2800 m of elevation. Its distribution corresponds to the Puna biogeographic province, that also extends in eastern Bolivia, northern Argentina and Chile ( Morrone 2006), which is a steppe shrublike formation with bushes 40 to 150 cm high. The area where Obrieniolus occur is close to the Coastal Peruvian Desert province, a narrow strip along the Pacific coast from northern Peru to northern Chile ( Morrone 2006), characterized by the extremely dry climate.

Obrieniolus robustus was found under rocks, in dry hills with grasses and sparse small shrubs. No specific host plant associations are known. The possibility of parthenogenesis is inferred based on the absence of males. This kind of reproduction seems to be frequent in the Andean species of Naupactini ( Lanteri and Normark 1995; del Río 2010).