Revision of the Radiolarian Genera Theocotyle, Theocotylissa and Thyrsocyrtis

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Abstract
Sixteen stratigraphically important species [Thyrsocyrtis bromia, T. hirsuta, T. rhizodon, T. robusta, T. tarsipes, T. lochites sp. nov., T. tensa, T. tetracantha, T. triacantha, Theocotyle conica, T. cryptocephala, T. nigriniae, T. venezuelensis, THEOCOTYLISSA gen. nov. et stat. nov., T. alpha (Foreman, 1973) comb. nov. (Theocotyle alpha), Theocotylissa auctor (Foreman, 1973) comb. nov. (Theocotyle auctor), Theocotylissa ficus (Ehrenburg, 1873) comb. nov. (Theocotyle ficus) and Theocotylissa fimbria (Foreman, 1973) comb. nov. (Theocotyle fimbria).] hitherto included in the Eocene genera Thyrsocyrtis and Theocotyle (with subgenera Theocotyle and Theocotylissa) are reexamined to clarify their morphologic variability and limits, and the new species Thyrsocyrtis lochites is described. The genus-level classification is modified by raising Theocotylissa to genetic status, and by using the subgenus Pentalacorys within the genus Thyrsocyrtis to segregate the species with large abdominal pores. Hybridization may be the cause of some morphologic features common to both Thyrsocyrtis (T.) rhizodon and Thyrsocyrtis (Pentalacorys) triacantha, through a portion of their stratigraphic range.

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