Upper Jurassic to Lower Cretaceous Dasycladales of the Northern Calcareous Alps: the state of knowledge
Restrictions and Problems
The spatial distribution of Dasycladales reveals patterns that cannot be explained only by their stratigraphic range. Moreover, the Alpine flora is characterized by a particular absence of the family Dasycladaceae, a group that is expected to be prominent in the Mesozoic. The question arises, which factors (e.g., paleobiogeography, stratigraphic range) influenced the distribution of Dasycladales.
Several problems hinder the interpretation: Modern data are scarce: Most available studies were conducted during the sixties and seventies of the last century, while recent systematic studies are scarce. Provincialism frequently affects the distribution of benthic shallow water organisms. Like their present-day equivalents, the Jurassic/Cretaceous Dasycladales seem to show endemism. This may be caused by oceanic basins between isolated carbonate platforms forming biogeographic barriers. Paleoecological requirements: e.g., N. socialis seems to be restricted to outer platform settings, but a detailed environmental reconstruction of most mentioned shallow water occurrences is absent.
6. Restrictions and Problems