Roe, K.J. 2013. Phylogenetic analysis of the freshwater mussel genus Ptychobranchus (Bivalvia: Unionidae). American Malacological Bulletin 31(2): 257-265. Available electronically.
(click the figure number to see the cladogram)
+----------------------- Obliquaria_reflexa
|
| +-- Lampsilis_siliquoidea
+--------------------+
--+ +-- Lampsilis_ornata
|
| +-------------------- Medionidus_conradicus
| |
+--+ +-- Cyprogenia_aberti
| +--------------+
| | +-- Dromus_dromas
+--+
| +-------------- Ptychobranchus_subtentus
+--+
| +----------- Ptychobranchus_jonesi
+--+
| +-------- Ptychobranchus_greenii
+--+
| +----- Ptychobranchus_occidentalis__2
+--+
| +-- Ptychobranchus_occidentalis__1
+--+
+-- Ptychobranchus_fasciolaris