Early Devonian Ostracods from Celtiberia (NE Spain) : taxonomy, palaeoecology, biostratigraphy, and biogeography

From numerous successive, well dated horizons of Early Lochkovian to Zlichovian age in Celtiberia (NE Spain), 93 neritic ostracod taxa of 40 genera are described and evaluated. 8 new species are named, further 10 new species are held in open nomenclature. The great potential of the Celtiberian Early Devonian for biostratigraphy is made available for work with ostracods. The ostracod records from outside Celtiberia are revised and redated. The ranges of many ostracod taxa are refined. The ostracod assemblages belong to the Eifelian Ecotype sensu Becker, 1975, but three recurring associations can be distinguished. Spinose forms of true Thuringian Ecotype do not occur. New faunistic data reveal the biogeographical relations in the Early Devonian between Gondwana and Baltica-Avalonia. The similarities among Celtiberian, other European, and NW African ostracod faunas are evaluated with due regard to their age relations. The Celtiberian faunas are closely related to those of Armorica. Neritic ostracods common to Celtiberia, Armorica and NW Africa corroborate the continuity of the Ibarmaghian Faunal Province. Due to the different ages and facies, there are only few similarities between the ostracod faunas of Celtiberia and those of nearby Cantabria and Montagne Noire. Faunal links between Celtiberia and Laurussia exist, but are scarce. Ostracod relations between Celtiberia and the Rheno-Ardennan basin, although not with certainty on species level, are evident from the Mittlere Siegen Schichten onward. The occurrence of beyrichiacean ostracods in Ibero-Armorica, at least from the mid-Lochkovian onward, disproves a wide Early Devonian "Rheic Ocean" between Baltica-Avalonia and Gondwana and supports the palaeogeographical reconstruction by McKerrow et al. (2000) that postulates the vicinity of Gondwana and Laurussia for Early Devonian times.