Centrocerum exornatum Click here for a larger view

Species examined.--C. divisum Martins & Monné, 1975 (holotype, paratype); C. exornatum (Newman, 1841).

Diagnosis.--Key characters: Ommatidial size coarse (Fig. 39b); prosternal process expanded apically (Fig. 18); mesal antennal spines present (Figs. 8b, 9b); pronotal impunctate regions usually present; pronotum without longitudinal rugosities or large, evenly-sized confluent punctures; femoral carinae absent; procoxal cavities closed laterally (Fig. 24); femoral apices rounded (Fig. 26d); elytra not metallic and without dense pubescence; procoxal cavities open posteriorly (Fig. 18); transverse ridges on pronotal disc absent; mesotibial carinae absent; shape of spine on antennomere three blunt (Fig. 28); femora clavate (Fig. 37b); elytral apices truncate to slightly spinose laterally; antennae spinose mesally on antennomeres 3-5; pronotum with widest point antemedially, gradually narrowing posteriorly; pronotum with distinct calli surrounded by coarse punctation, and dense pubescence posteriorly and laterally; elytra with pale maculations bordered on at least one side by black maculations. Length: 8-11 mm.

Distribution and Diversity.--Argentina, Brazil. Four species.

Discussion.--The results of the analysis show Centrocerum to be closely related to Elaphidion (Figs. 50, 56). This is due to one character (the linear antennomere shape) which has undergone many parallelisms. More character evidence is needed to fully understand its phylogenetic relationships.

The blunt spine on antennomere three, pale maculations on the elytra, and small size make this taxon strongly resemble those of Micropsyrassa and Minipsyrassa. Minipsyrassa has antennae spinose only to the third or fourth antennomere and has the pronotum widest at the middle. The elytra never have pale maculations in Minipsyrassa (although the basal half may be lighter). The distinct pronotal calli and dense pubescence present on Centrocerum will separate it from Micropsyrassa.