Tetragynetes, Kuschel, 2008

Kuschel, Guillermo, 2008, Curculionoidea (weevils) of New Caledonia and Vanuatu: Basal families and some Curculionidae, Mémoires du Muséum national d'Histoire naturelle 197, pp. 99-250 : 161-162

Genus TETRAGYNETES n. gen.

Type species: Trigonops dispar Saunders & Jekel.

DESCRIPTION. — Adelognathous. Head spherical, not retractable to eyes, not constricted behind eyes. Eyes small, strongly protruding, widest behind middle. Rostrum wider than long, deeper than wide, strongly elevated above antennal insertions, elevation steeply sloping anteriorly, falling vertically posteriorly, tapering basad in dorsal view to end in a tooth in lateral view; with an incised basa sulcus. Scrobes wide, foveiform some distance from eyes. Scape directed towards upper part of eyes, extended to near middle of prothorax, slender, gradually widening apicad; funicle with segments 1 and 2 subequal, other segments usually longer than wide; club at least twice as long as wide, first segment about one third of club length.

Prothorax wider than long, truncate at base, apical margin with short cilia across the underside and halfway up. Scutellum very small or concealed, glabrous. Elytra 12-striate, the additional two striae somewhat disorganized on interstsria 8; stria 10 complete, distinct throughout; dorsum in male usually flattened or depressed with a subcostate or flanged interstria 7. Fore coxae narrowly separate; mesosternal process wider than long, as wide as middle coax. Abdomen in male with five ventrites, in female with four visibles ones only as ventrite 4 intruded into abdominal lumen on to ventrite 5. Area between distal comb and tarsal groove carina wide, shiny, glabrous. Claws connate at base.

Male: tegmen with long, robust apodeme, membranous sides, and a pigmented dorsal sector without parameral lobes. Aedeagus extending well into thoracic lumen, 1.3 x longer than abdomen; aedeagal body nearly as long as the slender apodemes; internal sac very long, length equalling that of the whole weevil body, with a basal sclerite in the form of a very fine flagellum two thirds the length of exposed part of internal sac, flagellum sometimes retroverted.

Female: tergite 8 partly exposed beyond 7. Sternite 8 with articulating apodeme. Ovipositor firmish, not visibly pigmented, more than twice the length of the last two ventrites; proximal hemisternites several times longer tha distal ones, these with a stylus at apex. Spermatheca relatively robust; spermathecal duct very long, entangled on itself, pigmented.

DISTRIBUTION. — Vanuatu, Loyalty Is.

ETYMOLOGY. — ‘Tetragynétes’ is a Greek compound formed from ‘tetra’ = four, and ‘gyne’ = woman, with the suffix -etes of the Celeuthetes group of genera.

REMARKS. — Tetragynetes is unique within Celeuthetini by having the claws fused at base and, in females, by having ventrite 4 concealed in the abdominal cavity and shifted over ventrite 5. Marshall (1956), in his revision of this suprageneric taxon, transferred Trigonops dispar to Platysimus but somehow missed noticing these features as well as the fact that the elytra are 12-striate in the area above ventrite 2. The new genus is only remotely related to Platysimus . Two species present.

Tetragynetes dispar (Saunders & Jekel) comb nov. (from Platysimus ) Fig. 59

Trigonops dispar Saunders & Jekel, 1855: 295 , pl. 14: 4.

Heteroglymma hibisci – Paulian 1945: 187, figs 22-24 (Montrouzier, in error).

Platysimus dispar – Marshall, 1956: 119, fig. 47 (syn. meridionalis ).

Platysimus meridionalis – Thompson 1982: 89

Heteroglymma dispar – Paulian 1945: 187, 190, figs 15-20.

DESCRIPTION. — Derm black; vestiture, grey, squamose except for funicle, tarsi and a broad median area on undersisde. Head evidently strigose under vestiture. Prothorax rounded, with or without smooth median line; setae on pronotum directed caudad. Elytra across dorsum gently convex up to striae 5, laterad from here somewhat explanate to a sometimes upturned flange or costa made up in the main by interstria 7, fringed with short squamiform setae; elytral dorsum in female gently convex across up to interstriae 7, gently rounded on sides, interstria 5 slightly elevated at top of declivity, interstria 7 subcostate, interstria 9 behind humeral area not or hardly more convex than 8 or 10. Underside in male with long, more or less erect pilosity from prosternum to ventrite 2 inclusive and on the lower edge of middle and hind femora; underside in female with shorter, nearly recumbent pilosity.

Male: aedeagal body distinctly curving down apicad from below the ostial area to near apex where slightly curving up; aedeagal apex in dorsal view tapering all the way from the ostial area.

Length: 4.5-7.3 mm.

TYPE MATERIAL. — 1) Trigonops dispar : two syntypes mounted on same card, male on left, female on right. Lectotype male, 6.5 x 3.6 mm, and paralectotype female, ‘ New Hebrides, Trigonops dispar Jekel , ind. typ., Coll. Saunders’, Coll. Sharp, NHML, the sexing and handwriting on card by Sharp. 2) Heteroglymma meridionale: type specimens not seen. Identified non-type specimens with BPBM, IRSN, MNHN, NHML, NZAC, SRFP.

MATERIAL EXAMINED. — Vanuatu: Erromango, Tanna, Aneityum. Loyalty Is: Lifou, Maré. I. des Pins. 48 specimens .

ETYMOLOGY. — The species name ‘díspar’ is Latin for unequal, referring to the rather differently looking males and females.

REMARKS. — Specimens at IRSN, Brussels were wrongly identified as Trigonops platypennis ; one in MNHN, Paris as ‘ hibisci Montr. ’, which probably misled Paulian for him to have used the name for T. dispar specimens from Loyalty Is.