Wenlock Palaeoscenidiidae and Entactiniidae (Radiolaria) from the Cape Phillips Formation of the Canadian Arctic Archipelago

Abstract

Emended diagnoses encompassing forms described herein are proposed for the family Palaeoscenidiidae and the subfamily Palaeoscenidiinae. Diagnosis of the family Entactiniidae is emended to include only forms with latticed or spongy shells developed around a central spicule. This emendment permits mutual exclusivity of forms of the Palaeoscenidiidae and the Entactiniidae. Five genera of Palaeoscenidiinae are distinguished by skeletal ray arrangement. One of these, Palaeoscenidium, was illustrated previously in the literature. It is here emended to include only skeletons with four apical and four basal rays. Palaeoscenidium bicorne is reassigned to Palaeoephippium, n. gen. New genera are erected for 1) five-rayed spicules with one apical ray and four basal rays-Palaeopyramidium; 2) six-rayed spicules with two apical rays and four basal rays-Palaeoephippium; 3) six-rayed spicules with three apical rays and three basal rays-Palaeotripus; and 4) ten-rayed spicules with two apical rays and eight basal rays-Palaeodecaradium. Twenty-three new species belonging to the subfamily Palaeoscenidiinae and two new species of the family Entactiniidae are described. The Palaeoscenidiinae are shown to have given rise polyphyletically to the Entactiniidae.