Length: beetle in photo 5.1 mm
In genus Parimatidium antennomere eleven is longer than ten, while in the similar genus Imatidium the reverse is true. Parimatidium is made up of 5 described species, distributed from Venezuela to Paraguay. The food plants are oil palms in genus Elaeis (Arecaceae).
Note the feeding damage in the photos. An article in Science (Wilf, et al., 2000) discussed the evolutionary history of certain Tortoise Beetles that feed on Gingers. Finding the fossil records of feeding damage similar to that seen here, the authors proved that the beetles they studied "coexisted with the dinosaurs and outlived them, while never changing their diet" of Ginger leaves.
Photo location: Amazonas state, Brazil.
Determined by Dr. Lech Borowiec, Zoological Institute, University of Wrocław.
American Insects site