Achorius, 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 : 150-151

Genus ACHORIUS n. gen.

Type species: A. strigiceps n. sp. ( Mandalotus group.)

DESCRIPTION. — Small, rainforest floor litter species of the Mandalotus group of genera, usually coated with a thick, persistent crust of wax and dirt covering integument in particular of head, rostrum, prothorac and elytra.

Head retrievable to eyes, transversely coarsely strigose on covered surface, exposed part of head and forehead longitudinally strigose. Eyes slightly convex. Rostrum about as long as wide, gently widening apicad, deeply sulcate across at base, with a smooth sulcus on either side of midline; scrobes directed towards lower part of eyes. Antennae long, scape sinuous, extending to anterior part of prothoarax. Prothorax transverse, widest at anterior 1/3, with coarse granules topped with wachs glands and bifid hairs or scales, with a distinct basal collar at a lower level than disk. Scutellum concealed. Elytra coarsely striate, stria 10 incomplete. Fore coxae contiguous; mesosternal process at base in lateral view slightly proclinate to strongly overhanging; metasternum between middle and hind coxae short, flat. All tibiae distinctly mucronate, hind ones with open corbel; claws long, slender. Flightless species. Male: tegminal ring complete, dorsal part rather wide, lacking parameral lobes. Aedeagus long, extending well into metathoracic cavity, with apodemes distinctly longer than aedeagal body; internal sac with a very long, thin flagellum equalling the length of entire aedeagus, flagellum not articulated near base.

Female: tergite 7 truncate; sternite 8 with a weakly pigmented elongate blade, apical margin truncate, membranous, lateral margins well pigmented, with some setae, apodeme long, slender, embracing base of blade. Ovipositor long, as long as abdomen; proximal hemisternites firm but not pigmented, lacking rods, more than twice as long as distal ones; distal hemisternites at least partly pigmented, subcylindrical beyond vulva, with a few long setae in apical area, apparently lacking styli; vagina extending slightly cephalad from ovipositor; bursa long, about as long as distal hemisternites; spermataheca more or less baculiform, the stem gradually thickening apicad, with relativaley blunt tip, with duct and gland extension; duct as long as entire (external) genitalia, inserting at end of bursa.

DISTRIBUTION. — New Caledonia, endemic.

ETYMOLOGY. — ‘Achórius’ is derived from the Greek noun ‘achor, achóros’ = crust, to refer to the fact that all the specimens obtained had a thick incrustation of wax and dirt on the body.

REMARKS. — The lack of ocular lobes and cilia on the anterior margin of prothorax, the presence of an incomplete, interrupted stria 10, a distinct mucro on the hind tibiae and bifid hairs or scales seem to place Achorius near Paelocharis Broun of New Zealand. The rostral feature of a sulcus on either side of the midline, the presence of a flagellum in the internal sac, and a spermathecal duct insertion at the end of the bursa sets Achorius well apart within the Mandalotus group of genera. Because of thick coating of wax and dirt the underlying details of the surface are hidden if not first removed with solvents and ultra-sound cleansing. Four species are present, three are described below for having adequate numbers.

KEY TO SPECIES OF ACHORIUS

1. Rostrum, prothorax and elytra with short squamiform, usually well-curved setae. Elytra at base and before top of declivity with low but distinct elevations. Vestiture on elytral base largely confined to interstria 3 and basal angle. Eyes larger, with more than two dozen ommatidia ............................. 2 — Rostrum, prothorax and elytra with long, pointed, erect piliform setae. Elytra at base and before top of declivity lacking any elevations. Vestiture on elytral base consisting of an uninterrupted row of erect, bifid, apically backwards bent hairs or scales. Eyes small, with approximately one dozen ommatidia. 1.9-2.4 mm. New Caledonia......................................................................................... parvioculis

2. Basal angle of elytra blunt, not produced forward to a tooth. Mesosternal process in ventral view elongate-pentagonal, in lateral view overhanging considerably. 2.4-3.2 mm .......................... strigiceps — Basal angle of elytra produced forward to a prominent tooth. Mesosternal process in ventral view largely square, in lateral view falling nearly vertically, at most slightly proclinate. 2.4-3.2 mm. New Caledonia.................................................................................................................................. humeralis