Biology/Natural History: This group lives in the sediment and eats detritus which is picked up by extending the long palps into the sediment and moving detritus toward the mouth by ciliary action. Unlike other groups of clams, the gills are used for respiration only--not for feeding.

Yoldia is a protobranch bivalve, meaning its gills are bipectinate and it does not feed using its gills (see above). It is also a Palaeotaxodont because its shell valves are equal and have taxodont dentition.