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Brachiopoda: Systematics

The Phoronida, a probable close relative of the Brachiopoda, is the outgroup on the above cladogram. Both groups belong to the larger group Lophophorata.

Traditionally, the brachiopods have been split into two major groups, the Inarticulata and the Articulata. The Inarticulata got their name from the fact that they possess two valves that do not have an articulating hinge. The groups above that fit this description are the Lingulata and Obolellida; all others have articulating hinges. Recently it has been argued that hinge articulation is not a good character on which to make brachiopod groups. Thus, we break up the brachiopods as shown above, following Popov et al. (1993). It should be noted here that brachiopod phylogeny has been unstable in recent years, with various authors proposing that brachiopods are polyphyletic -- that is, that different brachiopod groups evolved separately from phoronid-like ancestors.

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