Barythaerus

Barythaerus is a small genus of marine bivalve molluscs of the family Thraciidae. The genus is endemic to the waters off southern New Zealand. Shells have been found at depths of 27-805 m. Live specimens have been found from bryozoan and shell substrates at intermediate depths (55–183 m).

Species
There are two recognized species:

Description
Barythaerus are small bivalves, with the larger species (Barythaerus cuneatus) reaching 5.5 mm in length. The shell is stout with a beak located in the posterior ⅓–¼ of the shell. Only the right valve has a prominent tooth. They resemble Parvithracia but are more stout and oblique.