Rhyncogonus duhameli Ramage, 2021

Ramage, Thibault, 2021, The missing link: Rhyncogonus Sharp in the Gambier Islands (Coleoptera Curculionidae, Entiminae, Rhyncogonini), Zootaxa 4908 (3), pp. 409-416 : 411-413

Rhyncogonus duhameli Ramage sp. nov.

( Figs. 3–5 )

http://zoobank.org/ urn:lsid:zoobank.org:act:5589EAF2-A2E6-457D-AE77-1610328F1558

Diagnosis. Rhyncogonus duhameli sp. nov. can be distinguished from other French Polynesia species of Rhyncogonus by the unique combination of the following features: F2 longer than F1; 4th interstriae more elevated basally, 6th and 7th interstriae more elevated medially; oblong scales with apex truncate, whitish and iridescent.

Etymology. This species is named after Alain Duhamel, who kindly taught the author how to prepare and describe weevil species. The species epithet is to be treated as a noun in the genitive case.

Type material. Holotype. FRENCH POLYNESIA • ³; Gambier Islands , Motu Teiku, 23°12’41.26”S– 134°58’30.32”W, 20m, on Myoporum sp. nov., 28.I.2016, J.-F. Butaud leg.; right mid-tarsi 2 and 3, hind tarsi 1–3 missing; MNHN.

Allotype. FRENCH POLYNESIA • ♀; Gambier Islands , Motu Teiku, 23°12’41.26”S– 134°58’30.32”W, 20m, on Myoporum sp. nov., 28.I.2016, J.-F. Butaud leg.; right F1–F11 missing; MNHN.

Description. Male holotype. Measurements (in mm): ROL: 1.5; ROW: 1.4; ROI: 93; EYL: 0.55; EYH: 0.28; EYI: 2; SL: 2.65; F1L: 0.6; F2L: 0.7; F3L: 0.45; F4L: 0.4; F5L: 0.35; F6L: 0.35; F7L: 0.33; F8L: 0.5; F9L: 0.35; F10L: 0.3; F11L: 0.28; PRL: 2.43; PRW: 2.65; PRI: 109; ELL: 6.9; ELW: 4.2; ELI: 164; FEL: 3.45; FEW: 0.9; FEI: 383.

Head ( Fig. 3 ). Eyes strongly convex, moderately tilted backwards. Rostrum broad and straight, slightly longer than wide. Scape straight, nearly cylindrical in its basal 3/4 th, moderately enlarged at apex, reaching first third of prothorax; F1 shorter than F2; antennal club lanceolate.

Prothorax ( Fig. 3 ). Slightly trapezoidal, 1.09x wider than long, with moderately, uniformly rounded sides; dorsum with median longitudinal ridge; anterior margin convex, slightly concave medially; posterior margin slightly convex. Prosternum without longitudinal carina between procoxae.

Scutellum. Very small, triangular.

Elytra ( Fig. 3 ). Somewhat oblong, 1.64x longer than wide, widest at mid-length; sides slightly convex at anterior 1/4 th, moderately convex at posterior 1/4 th; anterior carina absent; antero-lateral corners angular, forming 80° angle; lateral carina absent; interstriae slightly elevated, 4 th interstriae more elevated basally, 6 th and 7 th interstriae more elevated medially; in lateral view, dorsum slightly convex in anterior 2/3 rd, moderately convex apically.

Legs ( Fig. 3 ). Femora moderately narrowed basally, moderately enlarged medially, then moderately tapering toward apex, with ventral strong subapical concavity; tibiae almost straight, with blunt tooth along inner carina. Tarsomeres 1 and 2 two times wider apically than basally; tarsi 3 deeply bilobed; onychium nearly 1.5x longer than tarsi 3.

Aedeagus: apical half somewhat lanceolate, with apex broadly rounded (fig. 4).

Colour. Integument reddish brown.

Sculpture. Head with dense, strong punctation, except for impunctate longitudinal median stripe; vertex coriaceous. Prothorax with dense, large, very strong punctation, space between punctures convex. Scutellum with transverse thin carinae. Elytra with rounded, low processes on interstriae, these processes more developed at apex of elytra and on more elevated parts of interstriae. Legs coriaceous with dense punctation; with transverse short ridges on ventro-lateral median part of femora. Sternites with sparse, shallow punctation.

Pilosity. Subulate erect white scales, lanceolate appressed whitish scales evenly, sparsely distributed on head, prothorax and elytra, densely distributed on apex of elytra and legs. Oblong scales with apex truncate, whitish and slightly iridescent, evenly, densely distributed around eyes, on sides of prothorax, forming patches laterally and apically on elytra. Mandibles, gena, coxa, trochanter, base of ventral face of femora, tibiae, sides of sternites with long whitish setae. Scape with scattered, appressed whitish setae. F1 to F7 with appressed whitish setae becoming denser toward apex. F8 to F11 with dense dark silvery pubescence. F1 to F11 with few erect hairs at apex of each segment.

Female allotype. Measurements (in mm): ROL: 1.7; ROW: 1.6; ROI: 0.94; EYL: 0.58; EYH: 0.35; EYI: 1.64; SL: 2.8; F1L: 0.6; F2L: 0.7; F3L: 0.43; F4L: 0.4; F5L: 0.35; F6L: 0.35; F7L: 0.3; F8L: 0.45; F9L: 0.33; F10L: 0.25; F11L: 0.25; PRL: 2.6; PRW: 3.2; PRI: 1.23; ELL: 8.8; ELW: 5.25; ELI: 1.68; FEL: 4.15; FEW: 1; FEI: 4.15.

Differs from holotype male by prothorax 1.23x wider than long; body black with antennae and tarsi reddish brown; elytra densely but shallowly punctate; 2 nd interstria moderately elevated anteriorly; 4 th and 6 th interstriae strongly elevated anteriorly; 4 th interstria anteriorly and 6 th interstria along its length with tooth-like processes; lanceolate scales, yellowish and slightly iridescent, evenly and densely distributed on legs; lanceolate scales with apex truncate, yellowish and slightly iridescent, evenly and densely distributed on head and prothorax, very densely distributed on elytra; oblong scales with apex truncate, whitish and slightly iridescent, evenly distributed around eyes, beneath prothorax and on sternites ( Fig. 5 ).

Distribution. Rhyncogonus duhameli sp. nov. is known only from its type locality, Motu Teiku in Gambier Islands (fig. 1).

Figures

FIGURE 3. Rhyncogonus duhameli sp. nov., holotype. A. lateral habitus. B. dorsal habitus. Scale bar = 5.0 mm.

FIGURE 4. Rhyncogonus duhameli sp. nov., holotype. A. Pedon in lateral view. B. Pedon in dorsal view. Scale bar = 1.0 mm.

FIGURE 5. Rhyncogonus duhameli sp. nov., allotype. A. lateral habitus. B. dorsal habitus. Scale bar = 5.0 mm.