The paleobiogeography of the Jurassic brachiopods of the Alpine-Carpathian region
and adjacent areas is discussed on the basis of the distribution of ''distinctive
taxa''. The Jurassic microplates of the western part of Tethys and the present-day
''terranes'' of the Alpine-Carpathian region are outlined and their relationships
are discussed. The migration possibilities of the brachiopods in the Jurassic Tethys
were controlled mainly by plate/microplate movements and by changes in the oceanic
current system.
The Mediterranean microcontinent, isolated from the European and African shelves by
oceanic/deep-sea belts, was the homeland of the Mediterranean brachiopod province.
In the course of the Jurassic, the Mediterranean microcontinent moved, as part of
the African plate, away from Europe, the widening Alboran-Ligurian-Penninic oceanic
belt became a barrier preventing migration of brachiopods. By the end of the Middle
Jurassic the Tisza microplate detached from Europe and formed a ''stepping stone''
for brachiopod dispersal. At about the same time, the ''Hesperian Strait'' opened
between the basins of the Tethys and the Central Atlantic. The opening of this strait
resulted in a reorganization of the Tethyan current system. The westward flowing equatorial
currents which made a turn in the western corner of Tethys in the first half of the
Mesozoic, now ran to the west through the Hesperian Strait via the Central Atlantic
to the Pacific. This change produced a new pattern in brachiopod distribution: the
Mediterranean fauna successfully invaded the European shelf, at the same time the
Mediterranean province became impoverished.
