Myadora biconvexa Powell, 1927 Barythaerus biconvexus is a marine bivalve mollusc of the family Thraciidae.

[1] It is endemic to New Zealand,[2] with records off southern South Island and Stewart Island.

[3] Barythaerus biconvexus measures up to 5.1 mm (0.20 in) in length.

It is known from depths between 27–311 m (89–1,020 ft), with live specimens from bryozoan and shell substrates at intermediate depths (55–183 m).

This bivalve-related article is a stub.