Britannica
Sources used in this answer
How old is the fossil lamprey discovered in Illinois?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
agnathan
Lamprey (Lampetra) on rainbow trout.
The fossil lamprey discovered in Illinois dates back to the Middle Pennsylvanian period, making it more than 300 million years old.1
Prior to the 1968 report of this discovery, cyclostomesâthe group that includes modern lampreysâwere unknown in the fossil record because they lack the hard body parts that are typically preserved.1