Hederellids are extinct colonial animals with calcitic tubular branching exoskeletons. They range from the Silurian to the Permian and were most common in the Devonian period. They are more properly known as hederelloids because they were originally defined as a suborder by Bassler, who described about 130 species.[2] Although they have traditionally been considered bryozoans, they are clearly not because of their branching patterns, lack of an astogenetic gradient, skeletal microstructure, and wide range in tube diameters.[3] Work continues on assessing the true affinities of hederelloids, but they appear to be most closely related to phoronids and other lophophorates.[4][5]
Hederelloids encrusting a brachiopod from the Devonian of Ohio
SEM image of a hederelloid from the Devonian of Michigan (largest tube diameter is 0.75 mm)
References
^Taylor, P.D.; Wilson, M.A (2008). "Morphology and affinities of hederelloid "bryozoans""(PDF). In Hageman, S.J.; Key, M.M. Jr.; Winston, J.E. (eds.). Bryozoan Studies 2007: Proceedings of the 14th International Bryozoology Conference. Virginia Museum of Natural History. pp. 301–309. Archived from the original(PDF) on 2010-03-26. Retrieved 2011-03-26.
^Bassler, R.S (1939). The Hederelloidea. A suborder of Paleozoic cyclostomatous Bryozoa. pp. 87:25–91. {{cite book}}: |work= ignored (help)
^Wilson, Mark A.; Taylor, Paul D. ""Pseudobryozoans" and the problem of encruster diversity in the Paleozoic". PaleoBios (21 (supplement to no. 2)): 134–135.
^
Taylor, Paul D.; Wilson, Mark A. (2008). Hageman , S.J.; Key, M.M. Jr.; Winston, J.E. (eds.). Morphology and affinities of hederelloid "bryozoans"(PDF). Bryozoan Studies 2007: Proceedings of the 14th International Bryozoology Conference, July 1–8, 2007 (Special Publication 15 ed.). Boone, North Carolina. pp. 301–309. Archived from the original(PDF) on 2010-03-26.
