A new species of Sphenia (Bivalvia: Myidae) from the Gulf of Maine

A new species (Sphenia sincera ) is described from the Gulf of Maine. The new species remained undetected until now because it had been confused with juveniles of the well-known Mya arenaria and M. truncata, Sphenia sincera differs from species of Mya in the shape of the chondrophore, small adult size, short life span, and completely subtidal occurrence. The species is found in greatest abundance at depths from 30 to 63 m. Unlike species of Mya, S. sincera prefers soft silt-clay sediments where it may be a deposit-feeder as well as a filter-feeder. It appears to be a major food item for bottom-feeding fish.