A new UA radiolarian zonation for the Pliensbachian to Aalenian interval is established using 145 distinctive, widely-distributed species. The data are from biostratigraphic sections in: Queen Charlotte Islands, NE British Columbia, Baja California Sur, Japan, Oman, Turkey, Slovenia and Austria. A catalogue of 280 species (with revised taxonomy) is completed. For the zonation, about half these species were eliminated from the total dataset, because they are either rare (e.g. Danubea, Farcus, Pseudopoulpus, Rolumbus), long-ranging (e.g. Pseudocrucella, Orbiculiformella, Paronaella) or non-diagnostic with wide limits of variability (e.g. some species of Bagotum, Droltus, Parahsuum). Rich well-preserved radiolarians from thick continuous stratigraphic sections in Queen Charlotte Islands provide the most detailed record for this stratigraphic interval, and all collections are tied with North American ammonite zones or assemblages. An initial sequence of 25 UAs (including ammonite data) was determined from this material only. Subsequently, data from other areas were added and a global sequence of nine radiolarian zones was obtained. These zones can be correlated worldwide and link previously established UA zonations for the Hettangian-Sinemurian (Carter et al. 1998) and the Middle to Upper Jurassic (Baumgartner et al. 1995).
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