Kilikowska, A., M. Mioduchowska, A. Wysocka, A. Kaczmarczyk-Ziema, J. Rychlinska et al. 2020. The patterns and puzzles of genetic diversity of endangered freshwater mussel Unio crassus Philipsson, 1788 populations from Vistula and Neman drainages (eastern Central Europe). Life 10(7): 119 (1-23). Available electronically.
(click the figure number to see the cladogram)
+----- Unio_tumidus
--+
| +-- Unio_crassus
+--+
+-- Unio_nanus