The Tethys – a mosaic of biodiversity hotspots

Today biodiversity hotspots cluster mainly in the tropics. The high diversity in tropical floral and faunal communities is regarded as a product of low extinction (“museum”) and relative higher origination rates (“cradle”) due to higher molecular evolution compared to higher latitudes.

The Tethys Ocean reigned an extensive tropical area for a major part of the Phanerozoic. Sediments deposited in this tropical ocean and the fossils included are a treasure trove for palaeontologists. They allow glimpses into past biodiversity hotspots, into past faunal and floral communities and into centers of evolution.

Although the Tethyan realm is primarily known for exquisite marine fossil records, here the focus is on the vegetation of the surrounding continents. Plant macrofossil sites adjacent to the Tethys testify not only the early evolution of typical Mesozoic plant groups in the late Permian (Corystospermales, Bennettitales, and the conifer family Podocarpaceae in Jordan) but also the radiation of some of these groups in the Anisian and Carnian deposits of Austria and northern Italy. In contrast to the plant macrofossil sites surrounding the Tethys, plant microfossils are transported into the Tethys by rivers and deposited in marine sediments. These document for example plant survival during the Permian–Triassic mass extinction in South China or the Middle to Late Triassic biogeographical differentiation of the flora.