Phylogenetic relationships of Prosopium gemmifer, P. spilonotus, P. williamsoni, P. cylindraceum and P. coulteri species were determined based on variation at 37 allozyme loci, and compared with Stenodus and nine species of Coregonus . Of the three genera, Prosopium was the most distinct with Nei genetic distances to Coregonus of D =0·55—1·05 and to Stenodus of D =0·58—0·92. Stenodus and Coregonus were closely related but grou...