Tobochares kusad, 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 : 122-124

Tobochares kusad sp. n. Figs 2D, 5 A–B, 8A, 14A, 15, 17 A–B

Type material.

Holotype (male): "GUYANA: Region IX/ 2 48.531'N, 59 51.900'W, 170m/ Kusad Mts., Mokoro Creek/ main seepage area/ leg. Short, Isaacs, Salisbury/ 27.x.2013; GY13-1027-03B", "[barcode]/ SEMC1271353/ KUNHM-ENT" (CBDG). Paratypes (29): GUYANA: Region IX: Same data as type (4 exs., SEMC); same locality but leg. Short & Washington, 24.x.2013, GY13-1024-03C (13 exs., SEMC, CBDG, NZCS; includes DNA voucher SLE1021); same locality but "small rock pool with detritus", leg. Salisbury, 24.x.2013, GY13-1024-03A (12 exs., SEMC, CBDG).

Differential diagnosis.

This species can be distinguished from most species by the impressed striae running the full length of the elytra and its overall dark brown coloration (Fig. 2D). It is most similar to T. striatus from which it can be separated by the apex of the last maxillary palpomere only slightly darkened (Fig. 8A) at the tip (more extensive darkening in T. striatus ; Fig. 8B) and the eyes being slightly less emarginated laterally (compare Fig. 5B, D).

Description.

Size and form: Body length 2.0-2.4 mm. Body elongate oval, moderately dorsoventrally compressed. Color and punctation. Dorsum of head very dark brown to black, anterolateral margins of clypeus with paler preocular patches (Fig. 5 A–B); maxillary palps distinctly pale, with the apex of palpomere 4 slightly to significantly darker (Fig. 8A). Pronotum brown to dark brown with the lateral margins appearing slightly paler; elytra brown to very dark brown, slightly paler at lateral margins and posteriorly (Fig. 2D). Meso- and metathoracic ventrites and abdominal ventrites very dark brown (nearly black), with prosternum slightly paler; epipleura, legs, labial palps, and antennae distinctly paler, with antennal club slightly darker than proximal antennal segments. Ground punctation on head, pronotum and elytra moderately fine. Head. Eyes measuring ~150µm anteroposteriorly, continuous with outline of head, emarginate at lateral margin, narrowing to roughly two thirds of the width (Fig. 5 A–B). Thorax. Elytra with ten rows of serial punctures which are depressed into grooves running the full length of the elytra. Metafemora mostly glabrous on ventral face, with narrow band of pubescence along proximal third of anterior margin. Elevation of mesoventrite forming a low transverse carina with a prominent “tooth,” elevated to the same plane as the ventral surface of the mesocoxae. Metaventrite with distinct median ovoid glabrous area that is more than half of the total metaventrite length, and about half as wide as it is long. Abdomen. Abdominal ventrites uniformly and very densely pubescent, with small spicules interspersed amongst the setae. Aedeagus (Fig. 14A) with parameres about as wide as median lobe basally, parallel sided in basal half, then gradually narrowing in apical third; apex of parameres weakly expanded and bluntly rounded. Median lobe gradually tapering to a bluntly rounded apex, which slightly extends beyond the apex of the parameres; gonopore situated distinctly below the apex of the median lobe.

Etymology.

Named after Kusad Mountain in the South Rupununi region of Guyana, from where the species is known.

Distribution.

Only known from the type locality in Guyana (Fig. 15).

Biology.

The species was collected on a thin rock seepage flowing over granite that was associated with a small creek (Fig. 17 A–B). The seepage was mostly covered with dead leaves and detritus. Some specimens were also found in small pools in the rock that accumulated water from the seep as well as along the margins of the stream pool into which the seep flowed.