Bryozoans are greatly diversified and occur in various forms such as soft gelatinous colonies, fenestrate and squamous colonies, arborescent, chitinous, or calcareous, colonies, single- or multi-layered crustose(crust-like) colonies, colonies boring into hard substrates and those burrowing into soft material, penetrating by chemical and mechanical means respectively. Very little study has been performed on those species that bore or burrow so there is little knowledge as to the effects on the host, the adaptations made by the bryozoan to exist in such an environment, or how commonly this occurs.

Fossil records indicate that the bryozoan is over 500 million years old and have only recently been getting major scientific study. It is estimated that there could be thousands of species yet undiscovered.


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