any member of the class Stenolaemata, a group of marine-living animals within the invertebrate phylum Bryozoa (moss animals). About 550 genera of stenolaemates have been described. Only one of the four orders that make up the class, the Cyclostomata, is represented by living species; all members of the other three orders (Cystoporata, Trepostomata, and Cryptostomata) are now extinct. The stenolaemates are the oldest of all the bryozoans and date from the Early Ordovician Epoch (505 to 478 million years ago) on. The individuals (zooids) that make up a stenolaemate colony have narrow, cylindrical, sometimes very elongated tubes with calcified walls.
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