Preliminaryreport on the faunal associations of the uppermost Lower and Middle Ordovician of the Saxo-Thuringian region
Abstract
The preliminary review of the faunal associations occurring in the anchi-metamorphosed, tectonically strongly affected but richly fossiliferous Griffelschiefer Formation (Thuringia, Germany) based on almost 1500 specimens is presented. In the associations, which correspond to the Dapingian and early Darriwilian ages, the large asaphid trilobites (Asaphellus, Isabellinia, Megistaspis, Hungioides, Ogyginus) dominate. They are accompanied by common calymenids (Colpocoryphe) and illaenids (Ectillaenus), and rare nileids (Panderia?). Dalmanitid, pliomerid and cyclopygid trilobites as well as the phyllocarid crustaceans are entirely absent. Among graptolites, large rhabdosomes of Didymograptus hirundo strongly prevail. No dendroid graptolites have been recorded so far. The remains of the cephalopods are rather sparse and poorly preserved, enabling affiliation as Orthoceras sp. only. Very few and indeterminable remains of conulariids, echinoderms, bivalves, brachiopods, sponges and hyolithids supplement this review. The association is of rather deeper-water character and shows relation to the Iberia faunas, especially Arouca (Portugal) and the spain associations. The relations to the Perunica are less distinctive.