Procerosoma

Introduction

Procerosoma Lonsdale & Marshall is an uncommon Neotropical genus known from one Mexican female (P. prominens Lonsdale & Marshall) and one male and one female from Brazil (P. alini (Shatalkin)) (Lonsdale & Marshall in press). The translation of the generic name is 'slender-bodied', referring to the relatively long and thin thorax and legs characteristic of the genus.

The male of Procerosoma alini (and possibly the remainder of the genus) is distinct in that the head is wider than the thorax, and there is one pair of elongate genal 'antlers' that terminate in a bright white bulb. Behavioural observations have not been made, but it is assumed that these structures are associated with head-measuring competitions and male agonistic behaviour at lek sites, which has been recorded for a number of other clusiid genera.

Characteristics

Procerosoma is a relatively long, thin taxon defined by an inclinate anterior fronto-orbital bristle, an open cell bm, one pair of stripes on the face and scutum, a relatively small scutellum that is slightly angled dorsally, a reduction of the mid fronto-orbital bristle, and an absence of the ocellar, postvertical, acrostichal, and dorsal preapical tibial bristles (Lonsdale & Marshall in press). Internally, Procerosoma is characterized by a small pregonite and a basiphallus that is heavily setulose laterally.

Phylogenetics

Procerosoma and Sobarocephala together form the sister group to the small neotropical genus Chaetoclusia. These three genera comprise the subfamily Sobarocephalinae, which was described and revised by Lonsdale & Marshall (in press).

References

Lonsdale, O & Marshall, S.A. In press, a. Redefinition of the Clusiinae and Clusiodinae, description of the new subfamily Sobarocephalinae, revision of the genus Chaetoclusia and a description of Procerosoma gen. nov. (Diptera: Clusiidae). European Journal of Entomology.