A note on an atypical yellow perch, Perca flavescens Mitchill

The characteristic insertion of the predorsal bone is considered to be the most definitive means of separating the North American yellow perch, Perca flavescens from its European counterpart, P. fluviatilis . During a routine radiological examination of yellow perch collected for a taxonomic research project, a gradation between the two types was observed in a single fish. The specimen was subsequently cleared and stained for confirmation. This fish has a predorsal bone that is anterior to the first neural spine, as in P. fluviatilis , but the pterygiophore supporting the first dorsal spine extends between the second and third neural spines, as in typical P. flavescens . The male specimen was taken in a gillnet set in Long Point Bay of Lake Erie, Canada.