Tobochares canthus, Kohlenberg, Alex T. & Short, Andrew Edward Z., 2017

Kohlenberg, Alex T. & Short, Andrew Edward Z., 2017, Revision of the Neotropical water scavenger beetle genus Tobochares Short & Garcia, 2007 (Coleoptera, Hydrophilidae, Acidocerinae), ZooKeys 669, pp. 113-146 : 117-119

Tobochares canthus sp. n. Figs 3D, 6 C–D, 7D, 9A, 10A, 12D, 13B, 14H, 15, 18 A–B

Type material.

Holotype (male): "VENEZULEA: Amazonas State/ 5°23.207'N, 67°36.922'W, 125m/ Tobogan de la Selva; 8.viii.2008/ leg. A. Short, M. García, L. Joly/ AS-08-080b; old “tobogancito” / on seepage area w/ detritus", "[barcode]/ SEMC0877726/ KUNHM-ENT" (MIZA). Paratypes (28): VENEZUELA: Amazonas: same data as type (28 exs., SEMC, MALUZ, MIZA; includes 1 male mounted on SEM stub).

Differential diagnosis.

The lack of impressed striae on the elytra (Fig. 3D), strongly emarginated eye (Figs 6C-D), lack of spicules on the surface of the abdominal ventrites, and extremely broad glabrous patch on the metaventrite (Fig. 10A) all serve to easily separate this species from other Tobochares with the exception of T. emarginatus . It may be separated from T. emarginatus by the paler dorsal coloration and the shape of the aedeagus (Fig. 14H).

Description.

Size and form: Body length 1.7-2.0 mm. Body elongate oval, moderately dorsoventrally compressed. Color and punctation. Dorsum of head dark brown, frons darker (nearly black) laterally and around eyes, anterolateral margins of clypeus with paler preocular patches (Fig. 6 C–D); maxillary palps distinctly pale (Fig. 7D). Pronotum dark brown with the lateral margins paler; elytra dark brown, slightly paler at lateral margins and posteriorly. Meso- and metathoracic ventrites and abdominal ventrites very dark brown, with prosternum slightly paler; legs, labial palps, and antennae distinctly paler. Ground punctation on head, pronotum and elytra moderately fine. Head. Eyes measuring ~90µm anteroposteriorly, continuous with outline of head, emarginate at lateral margin, narrowing to about a fourth of the width (Fig. 6 C–D). Thorax. Elytra with punctures loosely organized into rows. Metafemora mostly glabrous on ventral face (Fig. 12D). Elevation of mesoventrite forming a low transverse carina, not quite elevated to the same plane as the ventral surface of the mesocoxae (Fig. 9A). Metaventrite with distinct median ovoid glabrous area that is more than half of the total metaventrite length, and nearly as wide as it is long (Fig. 10A). Abdomen. Abdominal ventrites uniformly and densely pubescent (Fig. 13B). Aedeagus (Fig. 14H) with parameres narrow, slightly less than half as wide as the median lobe; generally straight and parallel sided along entire length; apex of parameres not expanded, slightly tapered to a blunt tip on the medial corner; apex of median lobe distinctly surpassing the apex of the parameres; gonopore situated just below the apex of the median lobe.

Etymology.

Named after the condition of the eyes, in which a lateral canthus of the frons partially divides them into lower and upper surfaces.

Distribution.

Known only from the type locality in Venezuela (Fig. 15).

Biology.

This species was collected on a rock seepage along the margin of the Rio Coromoto (Fig. 18 A–B). The seepage drains water from the surrounding area and is not fed directly by the creek itself. The rock surface had scattered leaves and detritus, as well as algae in some patches.