Original paper

Review of the Beothuka terranova assemblage and characteristics of the middle Arenig (Ordovician, latest Floian) radiolarian assemblage from the Cow Head Group, Newfoundland

Won, Mun-zu; Iams, William J.

Abstract

The radiolarian fauna assigned to theBeothuka terranova assemblage from theIsograptus victoriae lunatus graptolite Zone of the Cow Head Group, Newfoundland is a middle Arenig (late Floian) radiolarian assemblage. This assemblage is reviewed and is shown to include no Beothuka terranova terranova. Rather, the assemblage name is based on the fact that the Beothuka spongiosain this fauna was originally misidentified as Beothuka terranova. As well, the Beothuka terranovaassemblage was originally established solely on the presence of Beothuka terranova and has been regarded as late Floian. However, Beothuka terranova was present during the entire Floian with the exception of the Isograptus victoriae lunatus Zone of latest Floian. It should be noted that the radiolar- ian assemblage from the Isograptus victoriae lunatus Zone of the Cow Head Group differs from the "Beothuka terranova assemblage" first introduced from the Didymograptellus bifidus graptolite Zone of the Valhallfonna Formation, Spitsbergen, in which it includes the first diversification of Antygoporawith respect to shell meshwork structure and spine development, and the first appearance of Antygopora intermediata n. sp., Parabeothuka irregularia, Beothuka maletziana n. sp., and Parechidnina sphaeroidea. Importantly, it contains no Beothuka terranova terranova possessing bipolar spines and no Beothuka aitchisoni, which were plentiful in earlier assemblages. This assemblage contains 11 genera, and 23 species, two of which are new.

Keywords

cow head groupmiddle arenig (latest floian)ordovicianradiolaria