Elytrurus, Boisduval, 1835

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 : 139-141

Genus ELYTRURUS Boisduval

Elytrurus Boisduval, 1835: 400 (type species E. cinctus Boisduval ). — Schoenherr 1842: 238. — Lacordaire 1863: 147. — Fairmaire 1880: 207. — Faust 1897: 230. — Marshall 1938: 71 (syn. Elytrogonus ). — Paulian 1945: 193.

Elytrogonus Guérin-Méneville 1841: 126 (type species E. griseus Guérin ). — Lacordaire 1863: 148. — Faust 1897: 231.

DESCRIPTION. — Head not retractable to eyes. Rostrum continuous with forehead, lacking saddle (depression) or sulcus; epistome lacking raised edges, not surrounded by groove; scrobes sulciform, directed towards lower half of eyes. Scape directed towards middle of eyes, passing front margin of prothorax; funicle with elongate antennites; club fusiform. Prothorax truncate at base, rounded on sides, in dorsal view lacking a distinct apical collar or basal rim, granulate. Scutellum exposed, transverse, glabrous. Elytra lacking humeral callus, curved at base, falling vertically at base, with more than ten striae; laterodorsal margin usually costate; apex with a pair of tubercles or processes.

Fore coxae contiguous; middle coxae separated by about a width of antennal club, hind coxae wide-apart; metasternum about as long as a mid-coxal diameter; mesopleurites fused but suture traceable; metepisternal suture complete. Hind tibiae with two combs outwards from tarsal grooves, combs separated by a bare oblique bevel; all tibiae mucronate in both sexes, between mucro and lower apical angle with silky pubescence in male. Claws free.

Male: tergites 1-4 very pale, 5-7 gradually more intensely pigmented and pilose apicad, lacking pruinosity (because of flightlessness), tergite 7 almost entirely pigmented and pilose, shallowly emarginate. Tergite 8 exposed beyond 7. Sternite 8 reduced to a pair of strongly transverse plates. Sternite 9 with symmetrical blade; apodeme robust. Tegmen as long as aedeagal body, with long, slender, well-apart parameral lobes. Aedeagus with apodemes not quite as long as venter; body wider at base and sides of ostial area, completely sclerotised; apodemes as long as aedeagal body; internal sac exposed, extending not quite to end of apodemes, lacking sclerites; gonopore at the very base of internal sac.

Female: tergites 7 and 8 moderately compressed, subtectiform, tergite 8 concealed under 7. Sternite 8 symmetrical, with straight apodeme; ovipositor entirely but weakly pigmented, less than one-half of length of sternite 8, strongly compressed, hemisternites completely divided across by a nearly unpigmented band, proximal hemisternites slightly longer than distal ones, the latter at apex dorsally rounded, ventrally sinuate, with long, heavily pigmented styli on middle od apex. Vagina extended cephalad by little more than length of oviposistor; bursa distinct, about as long as spermatheca high, ventrally invaginated; spermatheca slender, with long stem; gland long, slender, inserted halfway up the stem; duct unpigmented, twice as long as bursa, inserting ventrally near base of bursa.

DISTRIBUTION. — Vanuatu, Samoa, Fiji, Niue.

ETYMOLOGY. — ‘Elytrúrus’ is a Greek compound made up from ‘élytron’ = cover, case, and ‘oura’ = tail, because of processes extending in a number of species beyond the apical margin of elytra.

REMARKS. — The male and female features listed for the genus are based on the type species E. cinctus ; they may contain a mixture of generic and specific characters. Eight species are so far known from Vanuatu .

KEY TO SPECIES OF ELYTRURUS

1. Laterodorsal costa of elytra beyond middle abruptly ending or interrupted .................................... 2

— Laterodorsal costa of elytra beyond middle continuous, not abruptly ending or interrupted ...... 3

2 (1). Male: laterodorsal costa ending in a large, upturned lobe. Female: apical processes short, passing hind margin of elytra by distinctly less than a length of claw segment. 11.5-18.0 mm. Vanuatu ( Futuna) .......................................................................................................................................................... alatus – Male: laterodorsal costa ending in a small, not upturned tooth. Female: apical processes long, passing hind margin by a length or more of claw segment. 7.0- 15.5 mm. Vanuatu (Erromango, Tanna, Aneityum) .................................................................................................................................................. caudatus

3 (1). Rostrum lacking sublateral smooth lines (blunt carinae). 8.5-12.0 mm. Vanuatu (Erromango, Tanna, Aneityum) ................................................................................................................................ marginatus — Rostrum with smooth sublateral lines ........................................................................................................ 4

4 (3). Elytra with apical processes reduced to tubercles, not passing apex of elytral margin ............ 5 — Elytra with apical margin projecting distinctly beyond apex of elytral margin ................................. 6

5 (4). Prementum setose. Rostrum broadly impressed down middle, lacking a smooth median carina or line. 8.0-10.0 mmVanuatu (Espíritu Santo) ................................................................................ santicolus — Prementum bare. Rotrum not impressed down middle, with a broad smooth median line. 11.5- 14.5 mm. Vanuatu (Espiritu Santo) ..................................................................................................... convexus

6 (4). Prementum bare ........................................................................................................................................ 7 — Prementum setose ............................................................................................................................................ 8

7 (6). Sublateral smooth lines of rostrum subparallel; area between lines impressed all the way, if a median line present, not extending basad to frontal fovea. 9.5-19.0 mm. Vanuatu (Efate, Erromango, Tanna, Aneityum) .................................................................................................................................. serrulatus — Sublateral smooth lines of rostrum converging conspicuously basad, area between lines impressed only anteriorly above pterygia, convex across basal half; with a broad smooth median line extending basad to frontal fovea. Ll.5-13.0 mm. Vanuatu (Ambae, Pentecost) ................................................. aobae

8 (6). Pronotum and elytra with shiny pinkish white scales except for a broad bare conspicuous stripe on middle of prothorax and sutural area of elytra. Striae in front of puncta lacking granules, or these extremely small. Strial puncta not pupillated with large conspicuous scales. 9.5-13.0 mm. Vanuatu (Malekula, Efate) ......................................................................................................................... risbeci — Pronotum and elytra with dull greyish scales and at most a diffused darker median stripe, or uniformly dark because of minute scales leaving integument bare ................................................................ 9

9 (8). Scape, pronotum and elytra with dense vestiture covering most of integument, whence specimens appearing grey as a whole. Granules on pronotum and elytra minute, more so those in striae. 10.9-14.0 mm. Vanuatu (Ambrym, Epi, [Efate?]) .................................................................. divaricatus — Scape, pronotum and elytra with sparse, minute scales leaving most of integument exposed, whence specimens appearing black as a whole. Granules on pronotum and elytra large, including those in striae. 14.0-16.0 mm. Vanuatu (Ambrym) .................................................................................. ambrymensis