palaeoconcha

\\ˌ ̷ ̷ ̷ ̷ ̷ ̷ˈkäŋkə\ noun plural

Usage: capitalized

Etymology: New Latin, from pale- + Latin concha conch

in some classifications : a division of Protobranchia comprising simple extinct bivalve mollusks with thin shells and a primitive hinge and sometimes including also a few recent marine bivalves