Ambonus distinctus Click here for a larger view

Diagnosis.--Key characters: Ommatidia coarse (Fig. 39b); prosternal process between procoxae slightly expanded at apex (Figs. 18, 27); mesal antennal spines present (Figs. 8b, 9b); pronotum with impunctate regions but without rugosities or large confluent punctures; procoxal cavities closed laterally (Fig. 24); femoral apices rounded (Fig. 26); procoxal cavities open posteriorly (Fig. 18); mesotibial carinae absent; spine of antennomere three acute (Fig. 45a, b); femora clavate (Fig. 37b); pronotum without obvious constrictions; patches of dense yellow or white pubescence on elytra; antennae deeply sulcate dorsally (Fig. 45a); elytra strongly spined laterally at apex (Figs. 8f, 10f, 41a), slightly so suturally. Length: 12-19 mm.

Distribution and Diversity.--Argentina, Bolivia, Brazil, México, Paraguay, Uruguay. Eight species.

Discussion: Relationships of Ambonus to other elaphidiine genera are equivocal (Fig. 50). In the five shortest, fittest trees (Figs. 51-55), Ambonus consistently falls within the problematic clade containing Neocompsa + Ectenessa.

The patches of dense white and/or yellow pubescence on the elytra and/or pronotum, unspined femoral apices, clavate femora, median pronotal callus, and sulcate antennae easily characterize this genus. It differs from Trichophoroides in having coarsely sculptured integument and stronger antennal and elytral spines.