Radicitus surinamensis Short & García, 2014

Short, Andrew Edward Z. & García, Mauricio, 2014, A new genus of egg case-carrying water scavenger beetle from the Guiana Shield (Coleoptera: Hydrophilidae: Acidocerinae), Zootaxa 3835 (2), pp. 251-262 : 257-258

Radicitus surinamensis Short & García sp. n.

( Figs. 7 B, 8, 10)

Type locality. Suriname, Sipaliwini Department, Mt. Kasikasima, N 2°58.613’, W 55°24.683’, 400 m elev.

Type material. Holotype <male>: “ SURINAME: Sipaliwini District/ N 2°58.613’, W 55°24.683’, 400 m / Camp 4 (high), Kasikasima/ leg. A. Short; main seepage area/ 24.iii.2012; SR12-0324-01C/ 2012 CI-RAP Survey”, “[barcode]/ SEMC 1088423/ KUNHM-ENT” ( NZCS). Paratypes (38): SURINAME: Sipaliwini Department: Same data as holotype (35 exs.: SEMC, USNM, NMW, NMPC, NZCS); Grensgebergte Rock, Camp 2, rock seepages, 12.iii.2012, leg. A.E.Z. Short, SR12-0312-01A (3 exs.: SEMC); Summit of Tafelberg Tepui, Arrowhead Basin, flotation of wet rocks and moss, leg. Short & Bloom, SR13-0820-04A (1 ex.: SEMC).

Diagnosis. Size 4.9–5.6 mm. Elytra with coarse punctate striae (e.g. Fig. 4 A). Fifth ventrite with apicomedial glabrous patch that extends anteriorly about three-fourth the width of the ventrite. Parameres divided not divided into two projections ( Fig. 7 B).

The larger size and presence of punctate elytral striae and a glabrous patch on the fifth ventrite easily separate this species from R. granitum . The species is externally almost identical to R. ayacucho , which possesses a smaller glabrous patch on the fifth ventrite and divided aedeagal parameres.

Description. Color and punctation. Dorsum of head, pronotum and elytra very dark brown with all margins of pronotum and lateral margins of the elytra slightly paler. Anterolateral margins of clypeus with faint pale preocular patches. Thoracic and abdominal sterna and epipleura dark chestnut brown, with legs very slightly paler. Ground punctation on head and elytra moderately coarse; moderately coarse on elytral disc, and becoming extremely fine to almost obsolete laterally and posteriorly.

Head. Antenna with scape c. three times as long as pedicel, antennomere 3 subequal in length as 4 and 5 combined. Maxillary palps with palpomeres two and three subequal in length with apical palpomere slightly shorter.

Thorax. Elytra with rows of serial punctures strongly impressed in posterior half and laterally; serial punctures 5-8 times larger than surrounding, extremely fine ground punctuation. Mesoventrite with distinctive, large conical projection, which is flattened on the posterior face; the projection strongly elevated, rising to the same plane as the ventral surface of the mesocoxae; apex of projection set with a few setae. Metaventrite with distinct median glabrous area that is about as wide as long; total length of glabrous patch about half the metaventrite length. Metafemora with pubescence restricted to anterior fifth and extending distally to basal four-fifths.

Abdomen. Pubescence on ventrites 1-4 extremely fine and dense. Apex of fifth ventrite with a distinct glabrous patch along medioposterior margin, which extends three-fourths the width of the ventrite, and spans approximately the central third of the ventrite. Aedeagus ( Fig. 7 B) with parameres forming a single lobe, which is strongly constricted to a narrow, linear production in apical third; median lobe forming a narrow, tapering projection with a slight apical hook visible in lateral view.

Etymology. Named after the country from which it is known.

Distribution. Known from several localities in the interior of Suriname ( Fig. 8 ), including the summit of Tafelberg Tepui.

Remarks. All series were collected from seepages on exposed granite. Specimens from the Grensgebergte mountains were collected by submerging tufts of moss and roots from grasses growing on the seepages into tubs of water. The longer type series from Kasikasima, an enormous granite inselberg in southern Suriname, were collected by placing detrital debris that was on a granite seepage into pans of water ( Fig. 10 ). In Short (2013), this species is recorded as “ Hydrophilidae gen. nov. 3, sp. 1”.

Figures

FIGURE 4. Elytra of Radicitus spp. A) R. ayacucho, B) R. granitum.

FIGURE 7. Aedeagi of Radicitus spp. A) R. ayacucho, B) R. surinamensis, C) R. cf. granitum (Suriname), D) R. granitum (Venezuela).

FIGURE 8. Distribution of Radicitus spp.

FIGURE 10. Habitat of Radicitus surinamensis. A) Suriname, Grensgebergte Mountains (collecting event SR 12 - 0312 - 01 A). B) Suriname, Mt. Kasikasima (collecting event SR 12 - 0324 - 01 C).