Hoeh, W.R., D.T. Stewart, B.W. Sutherland & E. Zouros. 1996. Multiple origins of gender-associated mitochondrial DNA lineages in bivalves (Mollusca: Bivalvia). Evolution 50(6): 2276-2286. Available electronically.
(click the figure number to see the cladogram)
+-- None__1
+-----+
| +-- None__2
--+
| +----- Fusconaia_flava
+--+
| +-- Pyganodon_fragilis
+--+
+-- Pyganodon_grandis