Bagous argillaceus

ROBERTO CALDARA, CHARLES W. O’BRIEN & MASSIMO MEREGALLI, 2017, A phylogenetic analysis of the aquatic weevil tribe Bagoini (Coleoptera: Curculionidae) based on morphological characters of adults, Zootaxa 4287 (1), pp. 1-63 : 44

12. Bagous argillaceus group

Diagnosis. Scales smooth and shiny, with at most a very fine pit (char. 3.1). Supraocular setae very slender, long, erect and curved. Pronotum with complete median longitudinal sulcus or impression. Prosternum with scarcely evident canal, lateral margin more or less parallel and weakly raised (char. 31.1). Sclerites complex within tube of penis body with two posteriorly joined pairs of subapical sclerites, one submedian and the other sublateral (char. 84.4). Penis body with pseudo-orifice large to very large, apparent orifice strongly extended proximally, ventrally sinuate in area beneath orifice, lateral surface ventral to flange concave. Apodemes of spiculum ventrale strongly divergent, contiguous only at extreme base.

Remarks. This group is characterized by one synapomorphy from external morphology, the vestiture composed of almost smooth and distinctly shiny scales, and two synapomorphies from the genitalia. It was supported in all of the phylogenetic analyses. Prevously, B. affinis was placed in a separate monotypic group by O’Brien & Askevold (1995) due to two autapomorphies (scales on pronotal disc sublunate and distinctly emarginate and penis apodemes extremely short; char. 28.1 and 110.2, respectively) and the lack of four synapomorphies of the genitalia possessed by the other species of the B. argillaceus group—laminar orificial lateral sclerites present although sometimes only distinguishable at the apical portion (char. 74.1); orificial lateral sclerites obliquely uniformly raised (char. 75.1) and with basal margin distinct; orifice with lateral, transverse vertical sclerite (char. 83.1); and presence of a bursa with sclerites more or less bilobed and convex (char. 116.1). It is represented by four Palaearctic species, three of which with an eastern distribution, and two Indian species.

Species included. ORR: *³ Bagous affinis Hustache, 1926 ; ¹ Bagous laevigatus O'Brien & Pajni, 1989 ; PAL: *§¹ B. argillaceus Gyllenhal, 1836 , ¹ B. foersteri Hartmann, 1899 , *² B. fremuthi Dieckmann, 1975 , ¹ B. sulcicollis Hartmann, 1899 .