The Bryozoa have an incomplete
fossil record because of the poor fossilization-potential of non-calcified
forms such as the Ctenostomata.
Bryozoans appeared in the early Ordovician
and underwent a rapid burst of evolution. Particular groups
were dominant at different periods in Earth history.
became hugely important in the Cenozoic. Bryozoans of this order
express a high degree of colonial integration and every zooid
is connected. This may have involved some modification to the
structure of their colony to make effective use of water currents
The image below shows
geological ranges of key bryozoan Classes
and Orders throughout geological history. Please click the
image for a larger version.
Redrawn from Clarkson (1998)
Author: Luke Mander
Last updated: 20.11.05
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