Phyxelis Schönherr 1842

Anderson, Robert S., 2018, A Revision of the Weevil Genus Phyxelis Schönherr 1843 (Coleoptera: Curculionidae; Entiminae; Tropiphorini) in North America, Insect Systematics and Diversity (AIFB) 2 (5), No. 2, pp. 1-11 : 2

Phyxelis Schönherr 1842

Phyxelis Schönherr 1842: 122 . Gender masculine. Type species Barynotus rigidus Say , by original designation.

Geoderces Horn 1876: 70 . Gender masculine. Type species Trachyphloeus melanothrix Kirby (= Barynotus rigidus Say ), by original designation.

Diagnosis

Entiminae with mandible with scar marking point of attachment of deciduous cusp; pronotum with anterolateral margin with distinct rounded postocular lobe; antennal scape clothed with round, flat scales, not extended to anterior margin of pronotum, directed over middle of eye; metepisternal suture absent; hind tibia lacking outer bevel; tarsal claws free; body vestiture of small, erect, ramose/papillate scales which readily trap adherent dirt giving the body surface an encrusted appearance.

Description (modified from Bright and Bouchard [2008: 268]) Body small, length 3.1–5.1 mm, stout; body vestiture of small, erect, ramose/papillate scales which readily trap adherent dirt giving the body surface an encrusted appearance and scattered erect seta-like scales. Rostrum free, stout, about as long as wide at base, lateral margins slightly divergent to apex, epistoma with a number of elongate, fine setae on each side, nasal plate well-defined, delimiting ridge of plate narrowly U-shaped, carinate. Mandibles stout, with a distinct, obvious scar. Antennal insertion beyond midlength of rostrum; scrobe deeply impressed, curved ventrally at angle of about 45 degrees, directed towards lower one-third of eye, ventral margin of scrobe well-defined but short, dorsal margin lacking, scrobe open, and clearly visible dorsally. Antenna reddish brown, antennal scape club-shaped, extended almost to posterior margin of eyes and resting on or above eye when retracted next to head, with numerous flat, appressed scales; funicle of 7 desmomeres, basal two desmomeres elongate, remaining desmomeres about as long as wide, all desmomeres with setae; club distinct, conical, of 3 rhaptomeres, acutely pointed at tip. Eyes elongate-oval, flat, separated by about width of rostrum at base, partially covered by anterior edge of prothorax. Pronotum wider than long; anterior edge produced into a prominent postocular lobe. Elytra broad; scutellar shield not visible; sides broadly rounded; humeral angles rounded, flight wings absent; discal striae obsolete. Tibia truncate at apex, hind tibia mucronate at inner angle; claws free, simple. Female terminalia with tergite VIII well sclerotized, variously laterally compressed, rounded to almost carinate dorsally towards pointed apex, gonocoxite II distinct, rounded apically, lacking dorsal lobe, stylus present, very slightly subapical to apical; sternite VIII narrow, well-sclerotized, strongly laterally compressed, variously rounded to carinate or keeled ventrally towards pointed apex.

Natural history

Phyxelis species are flightless, ground dwelling weevils that occur in a variety of forested habitats primarily in eastern, but also into central and (sporadically, perhaps introduced) western North America. Based on habits of related taxa, larvae likely feed on roots but nothing is known of their life history or food plants. Specimens are generally collected in berlese or winkler extractions of leaf litter or ground debris; one species is known only from bird (quail) stomach contents. Two of the species are known only from females and appear to be parthenogenetic.