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Lamprey
A '''lamprey''' (sometimes also called '''lamprey eel''') is a jawless fish with a toothed, funnel-like sucking mouth. While lampreys are well known for those species which bore into the flesh of other fish to hematophagy|suck their blood, these species make up the minority. In zoology, lampreys are often not considered to be true fish because of their vastly different morphology (biology)|morphology and physiology.
Physical description
Lampreys live mostly in coastal and fresh waters, although at least one species, ''Geotria australis'', probably travels significant distances in the open ocean, as evidenced by the lack of reproductive isolation between Australian and New Zealand populations, and the capture of a specimen in the Southern Ocean between Australia and Antarctica. They are found in most temperate regions except Africa. Their larvae have a low tolerance for high water temperatures, which is probably why they are not found in the tropics.
Outwardly resembling eels, in that they have no scale (zoology)|scales, an adult lamprey can range anywhere from 13 to 100 centimetres (5 to 40 inches) long. Lampreys have no Fish anatomy#Types of Fins|paired fins, large eyes, one nostril on the top of the head, and seven gills on each side. The unique morphological characteristics of lampreys, such as their cartilage|cartilaginous skeleton, mean that they are the sister taxon (see cladistics) of all living jawed vertebrates (gnathostomes) and are not classified within the Vertebrata itself. This is disputed by some, who place lampreys within Vertebrata. Life cycle
Lampreys begin life as burrowing freshwater larvae (ammocoetes). At this stage, they are toothless, have rudimentary eyes, and feed on microorganisms. This larval stage can last five to seven years and so was originally thought to be an independent organism. They transform into adults in a metamorphosis which is at least as radical as that seen in amphibians. It involves a radical rearrangement of internal organ (biology)|organs, development of eyes and transformation from a mud-dwelling filter feeder into an efficient swimming parasite/predator that typically moves to the sea. The adult feeds by attaching its mouth to a fish, secreting an anticoagulant to the host, and feeding on the blood and tissues of the host. In most species this phase lasts about 18 months.
Some lampreys are landlocked and remain in fresh water, and some of these stop feeding when they leave the larval stage. The landlocked species are usually rather small.
To reproduce, lampreys return to fresh water, build a nest, spawn (biology)|spawn (that is, females lay eggs, males excrete semen), then invariably die. In ''Geotria australis'', the time from ceasing to feed at sea to spawning can be up to 18 months.
Fossils
Lamprey fossils are rare because cartilage does not fossilize as readily as bone. The oldest known fossil lampreys were from Early Carboniferous limestones,[From the Mississippian (geologic period)|Mississippian Mazon Creek lagerstätte and the Bear Gulch Limestone sequence.] laid down in marine sediments in North America: ''Mayomyzon pieckoensis'' and ''Hardistiella montanensis''.
In the 22 June 2006 issue of ''Nature'', Mee-mann Chang and colleagues reported on a fossil lamprey from the same Early Cretaceous lagerstätten that have yielded feathered dinosaurs, in the Yixian Formation of Inner Mongolia. The new species, morphologically similar to Carboniferous and modern forms, was given the name ''Mesomyzon mengae'' ("Middle lamprey"). The exceedingly well-preserved fossil showed a well-developed sucking oral disk, a relatively long branchial apparatus showing branchial basket, seven gill pouches, gill arches and even the impressions of gill filaments, and about 80 myomeres of its musculature.
Months later, in the 27 October issue of ''Nature'', an even older fossil lamprey, dated 360 million years ago, was reported from Witteberg Group rocks near Grahamstown, in the Eastern Cape of South Africa. This species, dubbed ''Priscomyzon riniensis'' still strongly resembled modern lampreys despite its Devonian age. Taxonomy
The taxonomy presented here is that given by Fisher, 1994. This work classifies lampreys as the sole living members of the class Cephalaspidomorphi.['''Cephalaspidomorpha''' is sometimes given as a subclass of the Cephalaspidomorphi.] The lampreys entail the single order '''Petromyzontiformes''' and family '''Petromyzontidae'''.['''Petromyzoniformes''' and '''Petromyzonidae''' are sometimes used as alternative spellings for Petromyzontiformes and Petromyzontidae respectively.]
Within this family, there are 40 recorded species in nine genera and three subfamilies:
- Subfamily Geotriinae
- Genus ''Geotria''
- * Pouched lamprey, ''Geotria australis'' (Gray,1851)
- Subfamily Mordaciinae
- Genus ''Mordacia''
- * ''Mordacia lapicida'' (Gray, 1851)
- * ''Mordacia mordax'' (Richardson, 1846)
- * ''Mordacia praecox'' (Potter, 1968)
- Subfamily Petromyzontinae
- Genus ''Caspiomyzon''
- * ''Caspiomyzon wagneri'' (Kessler, 1870)
- Genus ''Eudontomyzon''
- * ''Eudontomyzon danfordi'' (Regan, 1911)
- * ''Eudontomyzon hellenicus'' (Vladykov, Renaud, Kott and Economidis, 1982)
- * ''Eudontomyzon mariae'' (Berg, 1931)
- * ''Eudontomyzon morii'' (Berg, 1931)
- * ''Eudontomyzon stankokaramani'' (Karaman, 1974)
- * ''Eudontomyzon vladykovi'' (Oliva and Zanandrea, 1959)
- Genus ''Ichthyomyzon''
- * ''Ichthyomyzon bdellium'' (Jordan, 1885) - Ohio lamprey
- * ''Ichthyomyzon castaneus'' Girard, 1858 - chestnut lamprey
- * ''Ichthyomyzon fossor'' (Reighard and Cummins, 1916) - northern brook lamprey
- * ''Ichthyomyzon gagei'' (Hubbs and Trautman, 1937) - southern brook lamprey
- * ''Ichthyomyzon greeleyi'' (Hubbs and Trautman, 1937) - mountain brook lamprey
- * ''Ichthyomyzon unicuspis'' (Hubbs and Trautman, 1937) - silver lamprey
- Genus ''Lampetra''
- * ''Lampetra aepyptera'' (Abbott, 1860) - least brook lamprey
- * ''Lampetra alaskensis'' (Vladykov and Kott, 1978)
- * ''Lampetra appendix'' (DeKay, 1842) - American brook lamprey
- * ''Lampetra ayresii'' (Günther, 1870)
- * ''Lampetra fluviatilis'' (Linnaeus, 1758)
- * ''Lampetra hubbsi'' (Vladykov and Kott, 1976) - Kern brook lamprey
- * ''Lampetra lamottei'' (Lesueur, 1827)
- * ''Lampetra lanceolata'' (Kux and Steiner, 1972)
- * ''Lampetra lethophaga'' (Hubbs, 1971) - Pit-Klamath brook lamprey
- * ''Lampetra macrostoma'' (Beamish, 1982) - Vancouver lamprey
- * ''Lampetra minima'' (Bond and Kan, 1973) - Miller Lake lamprey
- * ''Lampetra planeri'' (Bloch, 1784)
- * ''Lampetra richardsoni'' (Vladykov and Follett, 1965) - western brook lamprey
- * ''Lampetra similis'' (Vladykov and Kott, 1979) - Klamath lamprey
- * ''Lampetra tridentata'' (Richardson, 1836) - Pacific lamprey
- Genus ''Lethenteron''
- * ''Lethenteron camtschaticum'' (Tilesius, 1811)
- * ''Lethenteron japonicum'' (Martens, 1868)
- * ''Lethenteron kessleri'' (Anikin, 1905)
- * ''Lethenteron matsubarai'' (Vladykov and Kott, 1978)
- * ''Lethenteron reissneri'' (Dybowski, 1869)
- * ''Lethenteron zanandreai'' (Vladykov, 1955)
- Genus ''Petromyzon''
- * ''Petromyzon marinus'' (Linnaeus, 1758) - sea lamprey
- Genus ''Tetrapleurodon''
- * ''Tetrapleurodon geminis'' (Alvarez, 1964)
- * ''Tetrapleurodon spadiceus'' (Bean, 1887)
Some taxonomists place lampreys and hagfish in the phylum Chordata under the super-class Agnathostomata (without jaws). The other super-class of the phylum is Gnathostomata (jaw-having) and includes the classes Chondrichthyes, Osteichthyes, Amphibia, Reptila, Aves, and Mammalia.
Relation to humans
Uses
Lampreys have long been used as food for humans. During the Middle Ages, they were Medieval cuisine|widely eaten by the upper classes throughout Europe, especially during fasting periods, since their taste is much meatier than that of most true fish. King Henry I of England is said to have died from eating "a surfeit of lampreys".[Giant reticulospinal synapse in lamprey: molecular links between active and periactive zones., Brodin L. et al., Cell Tissue Res. 2006]. The axons of lamprey are particularly large and allow for microinjection of substances for experimental manipulation.
As pests
Sea lampreys have become a major Pest (animal)|plague in the North American Great Lakes after artificial canals allowed their entry during the early 20th century. They are considered an invasive species, have no natural enemies in the lakes and prey on many species of commercial value, such as lake trout. Since the majority of North American consumers, unlike Europeans, refuse to accept lampreys as food, the Great Lakes fishery has been adversely affected by their invasion. Lampreys are now found mostly in the streams that feed the lakes, with special barriers to prevent the upstream movement of adults, or by the application of toxicants called lampricides, which are harmless to most other aquatic species. However those programs are complicated and expensive, and do not eradicate the lampreys from the lakes but merely keep them in check. New programs are being developed including the use of chemically Infertility|sterilized male lamprey in a method akin to the sterile insect technique. Research is currently under way on the use of pheromones and how they may be used to disrupt the life cycle (Sorensen, ''et al.'', 2005). Control of sea lampreys in the Great Lakes is conducted by the U.S. Fish and Wildlife Service and the Fisheries and Oceans Canada|Canadian Department of Fisheries and Oceans. The work is coordinated by the Great Lakes Fishery Commission.
Lake Champlain, bordered by New York State, Vermont, and Quebec, and New York's Finger Lakes are also home to populations of sea lampreys whose high populations have warranted control. Lake Champlain's lamprey control program is managed by the New York State Department of Environmental Conservation, the Vermont Department of Fish and Wildlife, and the U.S. Fish and Wildlife Service. New York's Finger Lakes sea lamprey control program is managed solely by the New York State Department of Environmental Conservation.
Folklore
Lampreys are called "nine-eyed eels" (i.e., per side) from a counting of their seven external gill slits on a side with one eye and the nostril.
In literature
Vedius Pollio was punished by Augustus for attempting to feed a clumsy slave to the lampreys in his fishpond.
- ...one of his slaves had broken a crystal cup. Vedius ordered him to be seized and to be put to death in an unusual way. He ordered him to be thrown to the huge lampreys which he had in his fish pond. Who would not think he did this for display? Yet it was out of cruelty. The boy slipped from the captor’s hands and fled to Caesar’s feet asking nothing else other than a different way to die—he did not want to be eaten. Caesar was moved by the novelty of the cruelty and ordered him to be released, all the crystal cups to be broken before his eyes, and the fish pond to be filled in... – Seneca the Younger|Seneca,'' On Anger'', III, 40 http://home.triad.rr.com/warfford/Roman_Empire/slavery.html
"Lampreys have been seen before attacking a human in the great lakes. The lamprey let go a few seconds later after realizing its mistake. The man (who chose to be not named) was taken to the hospital with various injuries." From the novel 20000 leagues under the sea.
Christopher Warner, a character in Philip Larkin's early novel Jill (novel)|''Jill'' is said to have attended a fictional minor public school called Lamprey College.
Lamprey pies are an appreciated dish often referred in George R.R. Martin's popular fantasy series ''A Song of Ice and Fire''
Stephen King's novel Dreamcatcher (novel)|''Dreamcatcher'' has alien creatures that look and move like Lampreys, which are nicknamed in the novel, "shitweasles"
Notes
References
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External links
- ITIS report on the lampreys
- "Lamprey conservation"
- A Tree of Life diagram showing the relation of Lampreys to other organisms
- Lampreys as food, including recipes
- Lamprey skeletons
- "Scientists from South Africa discover world's oldest fish fossil" News report on 27 October 2006 ''Nature'' article.
- Alok Jha, Perfect lampreys show little change in 125 m years ''The Guardian'' (22 June 2006)
- Scientists find lamprey a 'living fossil'
Category:Fish of the Pacific
Category:Vertebrates without jaws
Category:Edible fish
be-x-old:Міногі
Related Images- Basic external anatomy of the lamprey
- Larger lamprey in a restaurant tank waiting to be cooked and served.
- Portuguese Lamprey rice.
Sources: StartLearningNow, Wikipedia | Usage license: GNU FDL
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