Tepuidessus grulai Kodada & Hendrich & Balke 2018, sp. nov.

Abstract

<i>Tepuidessus grulai</i> sp. nov. <p> <b>Type locality</b>. Acopán Tepui, ca. 2,000 m, 5.194N 62.045W, Venezuela.</p> <p> <b>Holotype, male (ZSM): " Venezuela</b>: Estado Boliver, puddles on rocks in Acopantepui base camp" / " 2022m, 14.xi.2015, 5.19413°[N] -62.04478°[W], (VEN 6 /Nov2015)" / " Holotype <i>Tepuidessus grulai</i> sp. nov., Kodada, Hendrich & Balke des. 2018" [red printed label]. <b>Paratypes:</b> 43 exs with the same label data as holotype (CHF, CKB, MIZA, NMPC, ZSM). Each paratype is provided with a red printed paratype label.</p> <p> <b>Description of holotype</b>. Habitus slightly broad oval, outline with particularly distinct discontinuity between pronotum and elytra (Figs 3–4). Pronotum broadest before its midlength. Elytra widest at about midlength. Total length: 1.8 mm; maximum width: 0.9 mm.</p> <p> <b>Colouration</b>. Black dorsally, dark brown to black ventrally (Figs 3, 4, 5).</p> <p> <b>Surface sculpture</b>. Head with distinct microreticulation and few setiferous punctures (Fig. 4A). Pronotum and elytron shiny (Fig. 3A), mostly polished and distinct microreticulation only visible along pronotal margins; whole surface with dense and coarse setiferous punctation, exceptionally coarse and deep on disc (Fig. 6C). Ventral surface microreticulate, abdominal ventrites 3–6 shinier; venter with distinct setiferous punctation; posterior margins of ventrites 3–5 without denticles (present in Neotropical genus <i>Bidessodes</i> Régimbart, 1895; see Miller & Bergsten 2016).</p> <p> <b>Structures</b>. Antenna stout, moniliform. Head without occipital line and with rounded clypeus (as in Fig. 4). Pronotum without lateral bead; with distinct and very deep basal striae (as in Figs 6A, C). Elytron with short and deep basal striae, but without sutural line, with distinct longitudinal depression on elytral disc roughly in middle of each elytron (as in Fig. 3B, arrow). Basal epipleural transverse carina absent. Metathoracic wings vestigial, reduced to short membranous vestiges without any sign of venation (Fig. 6). Pro- and mesotarsi appearing stout because tarsomeres 1–3 distinctly dilated laterally; metatrochanter moderately offset.</p> <p> <b>Male genitalia</b>. Median lobe of aedeagus simply curved, long in lateral view; in ventral view, slender and gently narrowed towards tip (Figs 7A, B); lateral lobes (parameres) bisegmented and of a general Bidessini type (see Biström 1988), tip of distal joint rounded (Fig. 7A) and with no obvious "nose" or hook (as in e.g. Balke <i>et al</i>. 2015: fig. 31; Biström 1988: fig. 15).</p> <p> <b>Female</b>. Dorsal and ventral surface dull due to well impressed microreticulation between surface punctation (Figs 3B, 4B, 5). Apical ventrite flattened before posterior margin, tip in lateral view beak-shaped (Fig. 6B).</p> <p> <b>Size variation</b>. Total length: 1.7–1.8 mm; maximum width: 0.7–0.9 mm.</p> <p> <b>Differential diagnosis</b>. Using the key of Miller & Bergsten (2016: 220), the new species from Acopán Tepui does not key out with <i>Tepuidessus</i>, but with <i>Papuadessus</i> Balke, 2001, a genus endemic to the Papuan region. The two <i>Papuadessus</i> species are morphologically rather divergent and considered members of one lineage only based on DNA sequence data (Balke 2001; Balke <i>et al</i>. 2013; Miller & Bergsten 2016). In the absence of any obvious morphological apomorphy that would group the species treated here with <i>Papuadessus</i>, or indeed any other genus, we opt for the pragmatic approach to assign it to <i>Tepuidessus</i>.</p> <p> <i>Tepuidessus grulai</i> <b>sp. nov.</b> differs from <i>T. breweri</i> by (1) much broader habitus with distinct outline discontinuity between pronotum and elytra, (2) well developed, long and deep basal striae on pronotum and elytra and (3) by unbordered apical abdominal ventrite. The median lobe of aedeagus is more narrowed than in <i>T. breweri</i> in lateral view.</p> <p> <b>Etymology</b>. Named after Daniel Gruľa, one of the collectors of the new species. It is a noun in the genitive singular.</p> <p> <b>Distribution</b>. Only known from the type locality (Fig. 8). This locality is situated around 140 km west of Mount Roraima, the locality of the other Bidessini species described from the plateau of a tepui.</p> <p> <b>Habitat</b>. Puddles on rocks of summit plateau of Acopán Tepui (Fig. 10).</p>Published as part of <i>Kodada, Jan, Hendrich, Lars & Balke, Michael, 2018, Tepuidessus grulai sp. nov. from Acopán Tepui in Venezuela (Coleoptera: Dytiscidae: Hydroporinae: Bidessini), pp. 561-572 in Zootaxa 4434 (3)</i> on pages 563-566, DOI: 10.11646/zootaxa.4434.3.10, <a href="http://zenodo.org/record/1292243">http://zenodo.org/record/1292243</a&gt