ABSTRACT
The lampreys are a very ancient lineage of vertebrates, with the fi rst recognized fossil found in the Devonian period showing little morphological changes in 360 million years (Gess et al. 2006). Extant lampreys are a small group of 43 species, including anadromous, landlocked, and purely freshwater taxa (Renaud 2011; Mateus et al. 2013). Over half the known species are small, non-parasitic, or brook lamprey forms, which never feed during their brief adult lives of six to nine months. The remainder feed as adults in a parasitic manner (Hardisty 1986a).
