What is "brook lamprey"

n. A small European lamprey, (taxlink Lampetra planeri species noshow=1).

The brook lamprey (Lampetra planeri, also known as the European brook lamprey and the western brook lamprey) is a small European lamprey species that exclusively inhabits freshwater environments. The species is related to, but distinct from, the North American western brook lamprey ( Lampetra richardsoni).