Taxonomy and phylogeny of the genus Theocorys (Nassellaria, Radiolaria) from the Eocene and Oligocene sequences in the Antarctic region

Abstract

Taxonomic and phylogenetic investigations were carried out on the Eocene and Oligocene radiolarians assignable to the genus Theocorys from submarine sections of the Southern Indian and Southern Atlantic Oceans. Several well-preserved theoperid species previously described under the genera Calocyclas, Cyrtocapsella or Theocorys are now grouped into Theocorys, and their phylogenetic relationships are discussed. Five species are described, of which three are proposed as new. They are : T. kerguelensis sp. nov., T. minuta sp. nov., T. saginata sp. nov., T. robusta comb. nov. and T. semipolita comb. nov. In addition, another new species, Calocyclas (?) nakasekoi, is described.