Crinoidea (Comatulida) from Pirabas Formation (Early Miocene), Pará State, Brazil

Abstract

The Pirabas Formation, a representative geological unit of the Brazilian marine Cenozoic, assembles a rich and diverse fossil record, which includes Comatulida crinoids, components of the faunal assembly of the Pirabas Sea. Samples from the B-17 Mine outcropping, Municipality of Capanema, and the Atalaia Beach, Municipality of Salinópolis, Pará State were analyzed, and hundreds of disarticulated ossicles of crinoid comatulids were found. Centrodorsals of crinoids of the species Sievertsella polonica Radwanska, Discometra rhodanica (Fontannes), of the genus Kiimetra Shibata & Oji, and the family ?Zygometridae were herein identified. The taxa have affinities with those already recorded in the Miocene of the Caribbean biogeographic province and are consistent with the faunal interchange that has existed between the Tropical East Pacific and the Tropical West Atlantic regions. The material suggests the Pirabas Sea as a center of origin for some taxa, while also strengthening possible connections from the Atlantic to the Central Paratethys, the Mediterranean, and the Indian Ocean.

Keywords: Pirabas Sea, Cenozoic, Miocene, echinoderms, crinoids, paleobiogeography.