Lampreys

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Lampreys
Sea lamprey (top), river lamprey (middle) and brook lamprey (bottom)

Sea lamprey (top), river lamprey (middle) and brook lamprey (bottom)

Systematics
Over trunk : Neumünder (Deuterostomia)
Trunk : Chordates (chordata)
Sub-stem : Vertebrates (vertebrata)
Superclass : Round mouths (Cyclostomata)
Class : Petromyzontida
Order : Lampreys
Scientific name
Petromyzontiformes
Berg , 1940

Lampreys (Petromyzontiformes) are an order of fish-like, phylogenetically basal vertebrates (Vertebrata), living fossils that have hardly changed for 500 million years. They have an eel-like , elongated body, which is covered with a fin-like back and tail hem. The animals have two eyes (for the designation "lamprey" see appearance ).

Lampreys were and are also used in the kitchen, where they were prepared as lamprets similar to eel. Due to the numerous protective provisions, this is hardly possible today. All types of lampreys are on the red list .

The Association of German Sport Fishermen , the Federal Agency for Nature Conservation and the Association of German Sport Divers have named the lamprey family Fish of the Year 2012.

Distribution area

Lampreys are predominantly found in coastal waters and freshwater in cold and temperate zones. The range is disjoint and includes Europe, cold and temperate Asia, North America, Patagonia , southeast Australia (including Tasmania ) and New Zealand . For at least one species, namely Geotria australis , it is assumed that it also covers considerable distances in open sea water. The reason for this assumption is that no isolated development can be determined between Australian and New Zealand populations.

Lampreys spawn in the upper reaches of streams and rivers. For this you need gravelly substrates, through which cool, oxygen-rich water flows (therefore they do not occur in the tropics).

Very strong have sea lamprey as neozoon in the North American Great Lakes spread, where they were introduced by ships and channels and have no natural enemies. There they have become a nuisance and threaten the local fish stocks. Traditionally and for other reasons (“ bloodsuckers ”) there is no market for them as food fish in North America . In addition, the animals are too heavily contaminated with environmental toxins due to their way of life. They are fought with traps (including artificial pheromone traps ) and special poisons in the upper reaches of the inflowing waters. Since lampreys are not fish biologically and are very different from fish in their body chemistry, it was possible to find toxins that are poisonous to lampreys but not real fish.

Appearance

Body structure of an adult lamprey (scheme)
1 nostril, 2 mouth with throat, 3  eye, 4  external gill slits, 5  body, 6  opening of the cloaca, 7  tail, 8  caudal fin, 9  posterior dorsal fin, 10  anterior dorsal fin
The mouth of a sea ​​lamprey

The still eyeless, worm-like larvae are called Querder . After hatching, they bury themselves in sandy sections of the river bed. The head remains free and fishes fine food particles ( plankton ) out of the water. Usually after 5 to 7 years there is a very radical transformation ( metamorphosis ) of the body structure to the adult animal.

Depending on the species, lampreys grow to be around 20 to 40 cm tall, in the sea up to 75 cm, sometimes even larger.

The adult animals have two eyes. The name "lamprey" goes back to the seven lateral gill slits that appear to be eyes and the (unpaired) nostril (i.e. nine "eyes" on each of the two sides of the body).

Lampreys do not have jaws . The round mouth is equipped with horn teeth and designed as a suction mouth.

Lifestyle and diet

Migratory species

Lampreys on an American char

In about half of the species that are counted among the lampreys, the adult animals migrate into the sea, where they live as parasites for up to 18 months , usually near the coast. The species in which this occurs include the sea and river lampreys, which are also common in Central Europe .

Their hosts are fish to which they suckle, drink blood and grate pieces of meat. Using special substances in their saliva, they inhibit blood clotting, which is why no blood clots develop in attacked fish. Researchers are trying to extract this substance from saliva for use in medicine and to dissolve blood clots. Larger, healthy fish usually survive such attacks and only retain typical circular scars, but smaller species, juveniles and sick fish can die from it. Larger lampreys occasionally attack people near the coast and suck their blood. However, the bites are not toxic to humans.

After a few years, the lampreys rise again to the upper reaches of a river to spawn. During the retreat into the freshwater waters, the intestine recedes. After the act of spawning, the animals die.

Stationary species

About twenty species of lampreys are stationary, non-parasitic freshwater inhabitants. The animals stay near the place where they spent the larval period and spawn here again. They are each closely related to large anadromous species living and are therefore related to as "satellite type", respectively, called anadromous Art. An example of such a stationary species is the brook lamprey . Other lampreys that only occur in freshwater are the Northern Italian lamprey , which only occurs in tributaries of the Pos, and the Ukrainian brook lamprey ( Eudontomyzon mariae ) , which only occurs in the catchment area of ​​the Danube .

In these lamprey species, the larvae burrow into the bottom of the water and feed on small organisms that they filter out of the water. After the larval period, they no longer eat any food. Even during the transformation into adult animals, the intestine recedes. The animals only spawn and then die.

The Danube endemic Danube lamprey ( Eudontomyzon danfordi ) deviates from this pattern of behavior. It is the only European lamprey species that parasitizes freshwater fish such as perch and chub.

Systematics

External systematics and evolution

The lampreys were and are recently again classified together with the hagfish (Myxinoidea) in the superclass of the round mouths (Cyclostomata). With the advent of the principles of cladistics in the late 1970s, the opinion prevailed that the round- mouthed taxon must be a paraphyletic taxon and that the lampreys are more closely related to the jaw- mouthed gnathostomata ( cartilaginous fish , bony fish and terrestrial vertebrates ) than with the hagfish. This is based on a number of common features that are said to have only formed after the hagfish split off, including above all the muscular bases of the fins, the nerve- equipped heart, the structure of the spleen and pancreas and various physiological properties.

Molecular biological studies showed, however, that the round mouths are monophyletic , i. H. The lampreys and hagfish have a recent common ancestral form from which no other recent group emerges. They share four unique microRNA families and 15 unique paralogies between primitive microRNA families.

The round mouths are said to have developed around 500 million years ago in the Cambrian from a last common ancestor of all vertebrates, which was, however, much more complex than the round mouths. The round mouths then went through a degeneration and lost many of the characteristics typical of vertebrates, the hagfish more, the lampreys less. Lamprey fossils that are 360 ​​million years old are quite similar to modern forms.

Analyzes of the genome of sea lamprey ( Petromyzon marinus ) show that the lampreys family have characteristics of a double gene duplication ( gene duplication ). The lampreys are thus the oldest vertebrate family in which this peculiarity has been proven. The genome enlargement took place in vertebrate history before the lampreys split off, i.e. more than 500 million years ago. It represented a formative event in the evolution of vertebrates, among other things because the additional genes enabled new adaptations in further development.

Many of the genes of the jaw-mouthed genes are already found in the sea lamprey (1.2 to 1.5 percent of the genetic make-up in humans), even some of the genetic regulators for paired limbs, although lampreys themselves only have an unpaired fin fringe on the belly and back.

Internal system

There are three families, 10 genera and about 47 to 49 species:

Geotria australis
Eudontomyzon danfordi
Eudontomyzon mariae
Lampetra tridentata

Lampreys for food

Lamprete with rice

Lampreys have been valued as so-called food fish since ancient times and are usually referred to as lamprets in the kitchen . The largest and also economically used representative of the lamprey is the sea ​​lamprey . Its meat is white and fine, comparable to eel , in taste "meatier" than the meat of most real fish.

In the Middle Ages, the lampposts of Nantes were so famous that Parisians drove to meet the traders. In the 19th century, hundreds of thousands of lamprets were caught and fried and offered marinated in vinegar and herbs in northern Germany . The smaller river lamprey (also called Bricke or Pricke ) was caught in the Elbe and Weser and grilled over charcoal until recently .

In France, Galicia and Portugal, lamprets are still on traditional menus today. A classic lamprete dish is lamproie à la Bordelaise , in which the pieces are steamed in a sauce made from Bordeaux wine , their own blood , raw ham, leek, onions and garlic.

Meanwhile, lampreys are endangered species in Europe and are only rarely offered. Only in the Baltic States are lampreys regularly offered in the markets and consumed grilled or smoked.

Individual evidence

  1. ↑ Parasites in the trap. In: the standard . Retrieved August 22, 2009 .
  2. ^ S. Silva, MJ Servia, R. Vieira-Lanero, S. Barca, F. Cobo: Life cycle of the sea lamprey Petromyzon marinus: duration of and growth in the marine life stage. In: Aquatic Biology. 18, 2013, pp. 59-62. doi: 10.3354 / ab00488 .
  3. ^ S. Silva, MJ Servia, R. Vieira-Lanero, F. Cobo: Downstream migration and hematophagous feeding of newly metamorphosed sea lampreys (Petromyzon marinus Linnaeus, 1758). In: Hydrobiologia. 700, 2013, pp. 277-286. doi: 10.1007 / s10750-012-1237-3 .
  4. ↑ Bloody lamprey attacks in the Baltic Sea. ( Memento of December 21, 2009 in the Internet Archive ) August 24, 2019.
  5. ↑ Roland Meier Gerst, Thomas Romig: The freshwater fish in Europe. Franckh-Kosmos, Stuttgart 2003, ISBN 3-440-09483-9 , p. 129.
  6. ↑ Volker Storch, Ulrich Welsch: Systematic Zoology. Fischer, 1997, ISBN 3-437-25160-0 , pp. 544-548.
  7. ↑ Christiane Delarbre, Cyril Gallut, Veronique Barriel, Philippe Janvier, Gabriel Gachelin: Complete mitochondrial DNA of the hagfish, Eptatretus burgeri: The comparative analysis of mitochondrial DNA sequences strongly supports the cyclostome monophyly. In: Molecular phylogenetics and evolution. 22 (2), 2002, pp. 184-192. doi: 10.1006 / mpev.2001.1045
  8. ↑ Shigehiro Kuraku, Kinya G. Ota, Shigeru Kuratani, S. Blair Hedges: Jawless fishes (Cyclostomata). In: SB Hedges, S. Kumar: Timetree of Life. Oxford University Press, 2009, ISBN 978-0-19-953503-3 , pp. 317-319.
  9. ↑ Jon Mallatt, Christopher J. Winchell: Ribosomal RNA genes and deuterostome phylogeny revisited: More cyclostomes, elasmobranchs, reptiles, and a brittle star. In: Molecular Phylogenetics and Evolution. Volume 43, Issue 3, June 2007, pp. 1005-1022 doi: 10.1016 / j.ympev.2006.11.023
  10. ↑ Jon Mallatt, J. Sullivan: 28S and 18S rDNA sequences support the monophyly of lampreys and hagfishes. In: Mol Biol Evol. 15 (12), Dec 1998, pp. 1706-1718. (PDF)
  11. ↑ Alysha M. Heimberg, Richard Cowper-Sal·lari, Marie Sémon, Philip CJ Donoghue, Kevin J. Peterson: microRNAs reveal the interrelationships of hagfish, lampreys, and gnathostomes and the nature of the ancestral vertebrate. In: PNAS . vol. 107, no. 45, November 9, 2010, pp. 19379-19383. doi: 10.1073 / pnas.1010350107
  12. ↑ a b Philippe Janvier: microRNAs revive old views about jawless vertebrate divergence and evolution. In: PNAS. Volume 107, No. 45, November 9, 2010. doi: 10.1073 / pnas.1014583107
  13. ↑ Axel Meyer: The lamprey genome gives insights into the vertebrate evolution . In spectrum of science . Issue 6, June 2013, pp. 12-14.
  14. ↑ a b c Catarina S. Mateus, M. Judite Alves, Bernardo R. Quintella, Pedro R. Almeida: Three new cryptic species of the lamprey genus Lampetra Bonnaterre, 1788 (Petromyzontiformes: Petromyzontidae) from the Iberian Peninsula . In: Contributions to Zoology. 82 (1), 2013, pp. 37-53.
  15. ↑ MJ Araújo, S. Silva, Y. Stratoudakis, Gonçalves, M., Lopez, R., Carneiro, M., Martins, R., Cobo, F., Antunes, C .: Sea lamprey fisheries in the Iberian Peninsula. In: A. Orlov, R. Beamish (Eds.): Jawless Fishes of the World. Volume 2, Cambridge Scholars Publishing, 2016, Chapter 20, pp. 115-148.

literature

Web links

Commons : Lampreys (Petromyzontidae)  - Collection of images, videos and audio files
Wiktionary: lamprey  - explanations of meanings, word origins, synonyms, translations