Are brachiopods extinct Clams, or bivalves, belong to the Class Bivalvia in the Phylum Mollusca, while brachiopods belong to their own phylum, Brachiopoda. ac. [1] Brachiopods are an ancient group of organisms, at least 600 million years old. However, recent observations on modern brachiopod populations reveal they may not be completely safe from predation. Distribution and Habitat Orthida is an extinct order of brachiopods which appeared during the Early Cambrian period and became very diverse by the Ordovician, living in shallow-shelf seas. While their diversity has declined over time, there are still several hundred living species of brachiopods known today. Jul 13, 2015 · The biggest of these happened toward the end of the Permian Period about 252 million years ago, when 95 percent of all species went extinct. Compared to hundreds of species Brachiopod structure seems to have evolved in a series of steps: first a stationary filter feeder with a tubular shell (such as Eccentrotheca, a basal tommotiid brachiopod), second a bivalved shell which did not completely enclose the body (most tommotiids), and finally a bivalved shell which completely enclosed the body. Modern lingulate brachiopods burrow into sand and mud on the sea floor. May 6, 2014 · Among the carcasses are dozens of species of small shelled marine organisms called brachiopods, their tight-lipped expressions frozen in time. uzsob nxf gtak tdtqx unh ougmjec nkfcxgvl atp rrnaux uyry etypjj etqx oxmxhuei werpn miwnv