Lamprey
| Lamprey Temporal range: Late Devonian–Holocene |
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| A European river lamprey (Lampetra fluviatilis) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Hyperoartia |
| Order: |
Petromyzontiformes Berg, 1940 |
| Families | |
† = extinct |
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† = extinct
Lampreys (sometimes also called, inaccurately, lamprey eels) are any 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" ( "to lick" + "stone"), though the etymology is uncertain.
Currently there are about 38 known extant species of lampreys. Although they are well known for boring into the flesh of other fish to suck their blood, only 18 species of lampreys are actually parasitic. The lampreys are a very ancient lineage of vertebrates, though their exact relationship to hagfishes and jawed vertebrates is still a matter of dispute.
Basic external anatomy of a lamprey
Adults superficially resemble eels in that they have scaleless, elongated bodies, and can range from 13 to 100 cm (5 to 40 inches) in length. Lacking paired fins, adult lampreys have large eyes, one nostril on the top of the head, and seven gill pores on each side of the head. The unique morphological characteristics of lampreys, such as their cartilaginous skeleton, suggest they are the sister taxon (see cladistics) of all living jawed vertebrates (gnathostomes), and are usually considered the most basal group of the Vertebrata. Instead of true vertebrae, they have a series of cartilaginous structures called arcualia arranged above the notochord. Parasitic lampreys feed on prey as adults by attaching their mouthparts to the target animal's body, then using their teeth to cut through surface tissues until they reach blood and body fluid. Although attacks on humans do occur, they will generally not attack humans unless starved. Non-parasitic lampreys, which are usually freshwater species, do not feed as adults; they live off reserves acquired as ammocoetes (larvae), which they obtain through filter feeding.
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