List of animal phyla
Brachiopoda: the lamp-shells, with a huge fossil record going back to the Cambrian. 12,000 species, of which 350 are still living (or 100 according to Clarkson).p158 They look rather like bivalves, and they do have an upper and lower part to the shell. However, their internal organisation is quite different.p395 They were the dominant inshore fauna (infauna) of the Palaeozoic, but were much reduced by the two main extinction events, the P/Tr and K/T. Bivalve molluscs took over their inshore habitats in the Mesozoic, and since then the brachiopods have been confined to deeper water, except for a handful of species.