Looking through some fish occurrence data and stumbled into something interesting, at least to me and those of us who have been messing around with Southern Brook Lamprey Ichthyomyzon gagei (Figure 1). In the headwaters of the Noxubee River there are 2 species of lampreys that have been identified the southern brook lamprey and the least brook lamprey Lampetra aepyptera (Figure 2) in proximity to each other.

This raises a couple of questions.

1. Are they truly different? What are the characters that are used in field to differentiate the 2.
2. Assuming reliable field identification, do they co-occur? If they do why might that be? If they do not, why might that be?
3. We can do a pretty good job catching ammocoetes, but if we do can we tell them apart?

Figure 1. A southern brook lamprey ammocoete captured in a tributary of the Noxubee River in 2018.

Figure 2. Image of a least brook lamprey. Source