The Devonian trilobites of Brazil: A summary

Abstract

Devonian trilobites are found in three major Paleozoic intracratonic basins of Brazil (Amazonas, Parnaíba, and Paraná). The trilobites represent the families Homalonotidae, Dalmanitidae, and Calmoniidae. The distribution of these taxa in the Brazilian territory is summarized here because of their remarkable scientific and historical importance, and a revised taxonomy and lithostratigraphy of the Devonian (Pragian – Famennian) trilobites from Brazil is presented, based on new research and recent literature. Homalonotids and dalmanitids are relatively cosmopolitan, whereas calmoniids are more endemic and seem to have been restricted to marine cold-waters of the southern hemisphere (Malvinokaffric Realm). Although the trilobites within the Brazilian intracratonic basins are approximately contemporaneous, they show various patterns of endemism and biogeographical affinities with other Malvinokaffric areas such as Bolivia, South Africa, and the Falkland (Malvinas) Islands. At family level, therefore, trilobite diversity from Brazil is comparatively low, which may indicate biogeographical filtering related to the distance and/or remoteness of the Brazilian basins from more open oceanic waters.