Ostracods from the Upper Ordovician Borenshult fauna, Sweden

摘要

The Borenshult locality was a temporarily exposed, richly fossiliferous locality with the Hirnantia fauna. It yielded a rich and diverse ostracod assemblage, the Harpabollia harparum association. This association differs from other Upper Ordovician and Llandoverian ostracod faunas of Baltoscandia. In terms of graptolite zonation, the age of the H. harparum association may be characterised as extraordinarius-persculptus. The age and the fact that the H. harparum association occurs together with macrofossils typical of the Hirnantia-Dalmanitina fauna suggest that it may be regarded as part of the Hirnantia fauna in a wider sense. The record of the characteristic taxa of this particular association from the Carnic Alps and Bohemia suggests an immigration of the most characteristic members of the H. harparum association into the Baltoscandian Palaeobasin from higher palaeolatitudes. The data suggest that collection from the debris at Borenshult provided not only Hirnantian material, but also material from the pre and post-Hirnantian.