15.8: Marine Animals in Benthic Environments - Brachiopoda
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Brachiopods are marine animals that have hard valves (shells) on the upper and lower surfaces (different than bivalve mollusks that have a left and right shell arrangement). Brachiopod valves are hinged at the rear end so that the front can be opened for feeding or closed for protection. Brachiopod have a stalk-like pedicle that projects from an opening in one of the valves that attaches the animal to the seabed. Brachiopods appeared in the early Cambrian, and diversified in stages throughout the Paleozoic Era. One group, Lingula, has been around since the Early Cambrian (Figure 15.37). At their peak the brachiopods were among the most abundant filter-feeding and reef-building groups of organism, but their significance diminished after the great extinction at the end of the Permian Period.
|Figure 15.37. Lingula||Figure 15.38. Brachiopod (Ordovician)||Figure 15.39. Brachiopod (Mississippian)||Figure 15.40. Brachiopod (Paleocene)|