Abstract
Echyridella McMichael & Hiscock, 1958 is elevated to genus level on the basis of our interpretation of published molecular data. A new species of freshwater mussel, Echyridella onekaka, is described from the north-western South Island of New Zealand. Diplodon menziesi lucasi Suter, 1905 is resurrected from synonymy under E. menziesii (Gray, 1843) as a distinct species of Echyridella.