Abstract

SANCHEZ, Teresa M.. Taxonomic position and phylogenetic relationships of the bivalve Goniophorina Isberg, 1934, and related genera from the early Ordovician of northwestern Argentina. Ameghiniana [online]. 2006, vol.43, n.1, pp.113-122. ISSN 1851-8044.

On the basis of collections from Tremadoc and Arenig successions of northwestern Argentina, the affinities of Goniophorina Isberg, 1934, are reassessed. Studied material includes ucumariids, lipanellids, Goniophorina , and other specimens for which the new genus Lossella is proposed with the new species L . juancruzi sp. nov. as type species. Goniophorina and Lossella are grouped in the new family Goniophorinidae. Synapomorphies of goniophorinids, ucumariids, and lipanellids lead to the conclusion that Goniophorina integrates a major group of edentulous bivalves, a lineage of which -the ucumariidsprobably gave rise to Anomalodesmata. This fauna represents a rapid, local diversification event that is part of the west-Gondwanan bivalve radiation during the early Ordovician.

Keywords : Goniophorinids; Early Ordovician; Northwestern Argentina.