Category:Agnatha

Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes, placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin lampetra, which may mean "stone licker" (lambere "to lick" + petra "stone"), though the etymology is uncertain.[3] The plural fo

rm lamprey is sometimes seen.[4]

Distribution
Lampreys live mostly in coastal and fresh waters and are found in most temperate regions except those in Africa. Some species (e.g. Geotria australis, Petromyzon marinus, and Entosphenus tridentatus) travel significant distances in the open ocean,[10] as evidenced by their lack of reproductive isolation between populations. Other species are found in land-locked lakes. Their larvae (ammocoetes) have a low tolerance for high water temperatures, which may explain why they are not distributed in the tropics.

Lamprey distribution may be adversely affected by overfishing and pollution. In Britain, at the time of the Conquest, lampreys were found as far upstream in the River Thames as Petersham[citation needed]. The reduction of pollution in the Thames and River Wear has led to recent sightings in London and Chester-le-Street.[11][12]

Distribution of lampreys may also be adversely affected by dams and other construction projects due to disruption of migration routes and obstruction of access to spawning grounds. Conversely, the construction of artificial channels has exposed new habitats for colonisation, notably in North America where sea lampreys have become a significant introduced pest in the Great Lakes. Active control programs to control lampreys are undergoing modifications due to concerns of drinking water quality in some areas.[13]