Euxenus punctatus LeConte

Janicki, Julia & Young, Daniel K., 2017, Nemonychidae and Anthribidae of Wisconsin (Coleoptera: Curculionoidea), Insecta Mundi 2017 (579), pp. 1-36 : 8-9

Euxenus punctatus LeConte

(Fig. 7–8)

Euxenus punctatus LeConte 1876: 409 .

Description. Length 0.8–1.2 mm (head excluded). Body short, oval, convex, nearly glabrous, shining. Integument light to dark brown. Vestiture consisting of a few scattered, short, erect, almost invisible setae. Head retractile. Rostrum sinuate apically. Frons weakly convex, surface weakly punctate, reticulate. Pronotal width 1.4–1.5X length, widest at base; surface convex, with distinct, small, close, evenly spaced punctures; broadly angulate basally, with prominent basal transverse carina; laterally with two carinae on basal 1/2, these separated by distinct row of punctures, with upper carina distinct and elevated, lower carina less developed. Scutellum very small, almost invisible. Elytra about as wide as long, widest near middle, length 1.4–1.6X pronotal length; broadly rounded apically and laterally; striae punctate in irregular double rows; interstriae smooth. Abdomen very short. Pygidium vertical.

Diagnosis. Euxenus punctatus is the smallest primitive weevil species found in Wisconsin. It can be distinguished from other anthribids by the small size, compact, glabrous body, and by the retractile head. It can be distinguished from other species of Euxenus by elytral striae 2–7 with fields of confused punctures instead of uniseriate punctures, and by the microreticulate pronotal surface between the punctures.

Natural history. Valentine (1998) reared E. punctatus from the fungus Hypoxylon perforatum growing on dead twigs of common dogwood ( Cornus sanguinea ). He also observed this species on ridges of a reddish-brown pyrenomycete growing on dead, debarked branches that were partially buried in leaf litter. In Wisconsin, it has been found near a slime mold plasmodium.

Phenology. In Wisconsin, adults have been collected in July.

Collecting methods. The two Wisconsin specimens examined during this study from two counties represent a NEW STATE RECORD. One specimen was found near a slime mold plasmodium under bark of a fallen tree in a southern-mesic forest; the other was found at a point where one log was sitting atop another, at the edge of a small wooded patch near Helena Marsh, in the early afternoon.