HOME

TheInfoList



OR:

Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of
jawless fish Agnatha (, Ancient Greek 'without jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present ( cyclostomes) and extinct (conodonts and ostracoderms) species. Among recent animals, cyclosto ...
of the
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
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 Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
, which may mean "stone licker" ( "to lick" + "stone"), though the etymology is uncertain. ''Lamprey'' is sometimes seen for the plural form. There are about 38 known extant species of lampreys and five known extinct species. Parasitic carnivorous species are the most well-known, and feed by boring into the flesh of other fish to suck their blood; but only 18 species of lampreys engage in this
micropredator Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...
y lifestyle. Of the 18 carnivorous species, nine migrate from saltwater to freshwater to breed (some of them also have freshwater populations), and nine live exclusively in freshwater. All non-carnivorous forms are freshwater species. Adults of the non-carnivorous species do not feed; they live on reserves acquired as ammocoetes (
larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...
e), which they obtain through filter feeding.


Distribution

Lampreys live mostly in coastal and fresh waters and are found in most temperate regions. Some
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
(e.g. '' Geotria australis'', '' Petromyzon marinus'', and '' Entosphenus tridentatus'') travel significant distances in the open ocean, as evidenced by their lack of
reproductive isolation The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offsprin ...
between populations. Other species are found in land-locked lakes. Their
larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...
e (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 Conquest is the act of military subjugation of an enemy by force of arms. Military history provides many examples of conquest: the Roman conquest of Britain, the Mauryan conquest of Afghanistan and of vast areas of the Indian subcontinent, ...
, lampreys were found as far upstream in the
River Thames The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, se ...
as Petersham . The reduction of pollution in the Thames and
River Wear The River Wear (, ) in North East England rises in the Pennines and flows eastwards, mostly through County Durham to the North Sea in the City of Sunderland. At long, it is one of the region's longest rivers, wends in a steep valley through ...
has led to recent sightings in London and
Chester-le-Street Chester-le-Street (), also known as Chester, is a market town and civil parish in County Durham, England, around north of Durham and also close to Sunderland and Newcastle upon Tyne. It is located on the River Wear, which runs out to sea ...
. 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 The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
. Active control programs to control lampreys are undergoing modifications due to concerns of drinking water quality in some areas.


Biology


Anatomy

Adults superficially resemble eels in that they have scaleless, elongated bodies, and can range from in length. Lacking paired fins, adult lampreys have large eyes, one nostril atop the head, and seven
gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they ar ...
pores on each side of the head. The brain of the lamprey is divided into the
telencephalon The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. ...
,
diencephalon The diencephalon (or interbrain) is a division of the forebrain (embryonic ''prosencephalon''). It is situated between the telencephalon and the midbrain (embryonic ''mesencephalon''). The diencephalon has also been known as the 'tweenbrain in o ...
,
midbrain The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal ( alertness), and temperature regulation. The name comes from the Greek ''mesos'', ...
,
cerebellum The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebe ...
, and medulla. The
heart The heart is a muscular Organ (biology), organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as ca ...
of the lamprey is anterior to the intestines. It contains the sinus, one atrium, and one ventricle protected by the pericardial cartilages. The
pineal gland The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cy ...
, a photosensitive organ regulating
melatonin Melatonin is a natural product found in plants and animals. It is primarily known in animals as a hormone released by the pineal gland in the brain at night, and has long been associated with control of the sleep–wake cycle. In vertebrat ...
production by capturing light signals through the
photoreceptor cell A photoreceptor cell is a specialized type of neuroepithelial cell found in the retina that is capable of visual phototransduction. The great biological importance of photoreceptors is that they convert light (visible electromagnetic radiat ...
converting them into intercellular signals of the lamprey is located in the midline of its body, for lamprey, the pineal eye is accompanied by the parapineal organ. The buccal cavity, anterior to the
gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sp ...
s, is responsible for attaching the animal, through suction, to either a stone or its prey. This then allows the tongue to make contact with the stone to rasp
algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micr ...
, or tear at the flesh of their prey to yield blood. The pharynx is subdivided; the ventral part forming a respiratory tube that is isolated from the mouth by a valve called the velum. This is an adaptation to how the adults feed, by preventing the prey's body fluids from escaping through the gills or interfering with
gas exchange Gas exchange is the physical process by which gases move passively by diffusion across a surface. For example, this surface might be the air/water interface of a water body, the surface of a gas bubble in a liquid, a gas-permeable membrane, or a ...
, which takes place by pumping water in and out of the gill pouches instead of taking it in through the mouth. One of the key physical components to the lamprey are the
intestines The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...
, which are located ventral to the
notochord In anatomy, the notochord is a flexible rod which is similar in structure to the stiffer cartilage. If a species has a notochord at any stage of its life cycle (along with 4 other features), it is, by definition, a chordate. The notochord consi ...
. Intestines aid in osmoregulation by intaking water from its environment and desalinating the water they intake to an iso-osmotic state with respect to blood, and are also responsible for
digestion Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...
. Near the gills are the eyes, which are poorly developed and buried under skin in the larvae. The eyes consummate their development during metamorphosis, and are covered by a thin and transparent layer of skin that becomes opaque in preservatives.


Morphology

The unique morphological characteristics of lampreys, such as their cartilaginous
skeleton A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...
, suggest they are the sister taxon (see
cladistics Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived cha ...
) of all living jawed vertebrates ( gnathostomes). They 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. Hagfish, which resemble lampreys, have traditionally been considered the sister taxon of the true vertebrates (lampreys and gnathostomes) but DNA evidence suggests that they are in fact the sister taxon of lampreys. Studies have shown that lampreys are among the most energy-efficient swimmers. Their swimming movements generate low-pressure zones around the body, which pull rather than push their bodies through the water. Research on sea lampreys has revealed that sexually mature males use a specialized heat-producing tissue in the form of a ridge of fat cells near the anterior dorsal fin to stimulate females. After having attracted a female with pheromones, the heat detected by the female through body contact will encourage spawning. Due to certain peculiarities in their
adaptive immune system The adaptive immune system, also known as the acquired immune system, is a subsystem of the immune system that is composed of specialized, systemic cells and processes that eliminate pathogens or prevent their growth. The acquired immune system ...
, the study of lampreys provides valuable insight into the evolution of vertebrate adaptive immunity. Generated from a somatic recombination of
leucine-rich repeat A leucine-rich repeat (LRR) is a protein structural motif that forms an α/β horseshoe fold. It is composed of repeating 20–30 amino acid stretches that are unusually rich in the hydrophobic amino acid leucine. These tandem repeats com ...
gene segments, lamprey leukocytes express surface variable lymphocyte receptors (VLRs). This convergently evolved characteristic allows them to have lymphocytes that work as the
T cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell r ...
s and
B cell B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted o ...
s present in higher vertebrates immune system. Northern lampreys (Petromyzontidae) have the highest number of
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
s (164–174) among vertebrates.
Pouched lamprey The pouched lamprey (''Geotria australis''), also known as the korokoro or wide-mouthed lamprey, is a species in the genus ''Geotria'', which is the only genus in the family Geotriidae. The second species in the genus is the Argentinian lamprey ...
(''Geotria australis'') larvae also have a very high tolerance for free iron in their bodies, and have well-developed biochemical systems for detoxification of the large quantities of these metal ions. Lampreys are the only extant vertebrate to have four eyes. Most lampreys have two additional parietal eyes: a pineal and parapineal one (the exception is members of '' Mordacia'').


Adaptations

Different species of lamprey have many shared physical characteristics. The same anatomical structure can serve different functions in the lamprey depending on whether or not it is
carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other ...
. For example, non-carnivorous species use their teeth to scrape algae from rocks for food, rather than drilling into the flesh of hosts. The mouth and suction capabilities of the lamprey not only allow it to cling to a fish as a
parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...
, but provide it with limited climbing ability so that it can travel upstream and up ramps or rocks to breed. This ability has been studied in an attempt to better understand how lampreys battle the current and move forward despite only being able to hold onto the rock at a single point. Some scientists are also hoping to design ramps that will optimize the lamprey's climbing ability, as lampreys are valued as food in the Northwest United States and need to travel upstream to reproduce. The last common ancestor of lampreys appears to have been specialized to feed on the blood and body fluids of other fish after metamorphosis. They attach their mouthparts to the target animal's body, then use three horny plates (laminae) on the tip of their piston-like tongue, one transversely and two longitudinally placed, to scrape through surface tissues until they reach body fluids. The teeth on their oral disc are primarily used to help the animal attach itself to its prey. Made of keratin and other proteins, lamprey teeth have a hollow core to give room for replacement teeth growing under the old ones. Some of the original blood-feeding forms have evolved into species that feed on both blood and flesh, and some who have become specialized to eat flesh and may even invade the internal organs of the host. Tissue feeders can also involve the teeth on the oral disc in the excision of tissue. As a result, the flesh-feeders have smaller buccal glands as they do not require the production of anticoagulant continuously and mechanisms for preventing solid material entering the branchial pouches, which could otherwise potentially clog the gills. A study of the stomach content of some lampreys has shown the remains of intestines, fins and vertebrae from their prey. Although attacks on humans do occur, they will generally not attack humans unless starved. Carnivorous forms have given rise to the non-carnivorous species that feed on algae, and "giant" individuals amongst the otherwise small American brook lamprey have occasionally been observed, leading to the hypothesis that sometimes individual members of non-carnivorous forms return to the carnivorous lifestyle of their ancestors. Another important lamprey adaptation is its
countershading Countershading, or Thayer's law, is a method of camouflage in which an animal's coloration is darker on the top or upper side and lighter on the underside of the body. This pattern is found in many species of mammals, reptiles, birds, fish ...
, a form of
camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...
. Similarly to many other aquatic species, most lampreys have a dark-colored back, which enables them to blend in with the ground below when seen from above by a predator. Their light-colored undersides allow them to blend in with the bright air and water above them if a predator sees them from below. Lamprey coloration can also vary according to the region and specific environment in which the species is found. Some species can be distinguished by their unique markings – for example, ''Geotria australis'' individuals display two bluish stripes running the length of its body as an adult. These markings can also sometimes be used to determine what stage of the life cycle the lamprey is in; ''G. australis'' individuals lose these stripes when they approach the reproductive phase and begin to travel upstream. Another example is '' Petromyzon marinus'', which shifts to more of an orange color as it reaches the reproductive stage in its life cycle.


Lifecycle

The adults spawn in nests of sand, gravel and pebbles in clear streams. After hatching from the eggs, young larvae—called ammocoetes—will drift downstream with the current till they reach soft and fine sediment in silt beds, where they will burrow in silt, mud and detritus, taking up an existence as
filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
s, collecting detritus, algae, and microorganisms. The eyes of the larvae are underdeveloped, but are capable of discriminating changes in illuminance. Ammocoetes can grow from to about . Many species change color during a diurnal cycle, becoming dark at day and pale at night. The skin also has photoreceptors, light sensitive cells, most of them concentrated in the tail, which helps them to stay buried. Lampreys may spend up to eight years as ammocoetes, while species such as the
Arctic lamprey The Arctic lamprey (''Lethenteron camtschaticum''), also known as the Japanese river lamprey or Japanese lampern (''Petromyzon japonicus'' Martens 1868, ''Lampetra fluviatilis japonica'' (Martens 1868), '' Lampetra japonica'' (Martens 1868), '' L ...
may only spend one to two years as larvae, prior to undergoing a metamorphosis which generally lasts 3–4 months, but can vary between species. While metamorphosing, they do not eat. The rate of water moving across the ammocoetes' feeding apparatus is the lowest recorded in any suspension feeding animal, and they therefore require water rich in nutrients to fulfill their nutritional needs. While the majority of (invertebrate) suspension feeders thrive in waters containing under 1 mg suspended organic solids per litre (<1 mg/L), ammocoetes demand minimum 4 mg/L, with concentrations in their habitats having been measured up to 40 mg/L. During metamorphosis the lamprey loses both the
gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although ...
and the
biliary tract The biliary tract, (biliary tree or biliary system) refers to the liver, gallbladder and bile ducts, and how they work together to make, store and secrete bile. Bile consists of water, electrolytes, bile acids, cholesterol, phospholipids and ...
, and the
endostyle The endostyle is an anatomical feature found in invertebrate chordates and larval lampreys. It is an organ which assists chordates in filter-feeding. It is found in adult urochordates and cephalochordates, as well as in the larvae of the vertebra ...
turns into a
thyroid The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The ...
gland. Some species, including those that are not carnivorous and do not feed even following metamorphosis, live in freshwater for their entire lifecycle, spawning and dying shortly after metamorphosing. In contrast, many species are
anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...
and migrate to the sea, beginning to prey on other animals while still swimming downstream after their metamorphosis provides them with eyes, teeth, and a sucking mouth. Those that are anadromous are carnivorous, feeding on fishes or marine mammals. Anadromous lampreys spend up to four years in the sea before migrating back to freshwater, where they spawn. Adults create nests (called redds) by moving rocks, and females release thousands of eggs, sometimes up to 100,000. The male, intertwined with the female, fertilizes the eggs simultaneously. Being
semelparous Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered semelparous if it is characterized by a single reproductive episode before death, and iteroparous if it is characteri ...
, both adults die after the eggs are fertilized.


Classification

Taxonomists place lampreys and hagfish in the subphylum Vertebrata of the
phylum In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature ...
Chordata A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fi ...
, which also includes the invertebrate subphyla Tunicata (sea-squirts) and the fish-like Cephalochordata ( lancelets or Amphioxus). Recent molecular and morphological phylogenetic studies place lampreys and hagfish in the superclass Agnatha or
Agnathostomata Agnatha (, Ancient Greek 'without jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present (cyclostomes) and extinct (conodonts and ostracoderms) species. Among recent animals, cyclosto ...
(both meaning without jaws). The other vertebrate superclass is
Gnathostomata Gnathostomata (; from Greek: (') "jaw" + (') "mouth") are the jawed vertebrates. Gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates, including humans. In addition to opposing jaws, livi ...
(jawed mouths) and includes the classes
Chondrichthyes Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue. ...
(sharks),
Osteichthyes Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartil ...
(bony fishes),
Amphibia Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbo ...
, Reptilia,
Aves Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
, and
Mammalia Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
. Some researchers have classified lampreys as the sole surviving representatives of the Linnean
class Class or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used differently ...
Cephalaspidomorphi. Cephalaspidomorpha is sometimes given as a subclass of the Cephalaspidomorphi. Fossil evidence now suggests lampreys and cephalaspids acquired their shared characters by
convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...
. As such, many newer works, such as the fourth edition of ''
Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...
'', classify lampreys in a separate group called Hyperoartia or Petromyzontida, but whether this is actually a
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...
is disputed. Namely, it has been proposed that the non-lamprey "Hyperoartia" are in fact closer to the jawed vertebrates. The debate about their systematics notwithstanding, lampreys constitute a single
order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
Petromyzontiformes. Sometimes still seen is the alternative spelling "Petromyzoniformes", based on the argument that the type genus is '' Petromyzon'' and not "Petromyzonta" or similar. Throughout most of the 20th century, both names were used indiscriminately, even by the same author in subsequent publications. In the mid-1970s, the
ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...
was called upon to fix one name or the other, and after much debate had to resolve the issue by voting. Thus, in 1980, the spelling with a "t" won out, and in 1981, it became official that all higher-level taxa based on ''Petromyzon'' have to start with "Petromyzont-". The following taxonomy is based upon the treatment by FishBase as of April 2012 with phylogeny compiled by Mikko Haaramo. Within the order are 10 living genera in three families. Two of the latter are
monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...
at genus level today, and in one of them a single living species is recognized (though it may be a
cryptic species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each ot ...
): *''Geotria australis'' Gray 1851 (
Pouched lamprey The pouched lamprey (''Geotria australis''), also known as the korokoro or wide-mouthed lamprey, is a species in the genus ''Geotria'', which is the only genus in the family Geotriidae. The second species in the genus is the Argentinian lamprey ...
) *''Mordacia lapicida'' (Gray 1851) ( Chilean lamprey) *''Mordacia mordax'' (Richardson 1846) ( Australian lamprey) *''Mordacia praecox'' Potter 1968 (Non-parasitic/ Australian brook lamprey) *''Petromyzon marinus'' Linnaeus 1758 (
Sea lamprey The sea lamprey (''Petromyzon marinus'') is a parasitic lamprey native to the Northern Hemisphere. It is sometimes referred to as the "vampire fish". Description The sea lamprey has an eel-like body without paired fins. Its mouth is jawless, ...
) *''Ichthyomyzon bdellium'' (Jordan 1885) (
Ohio lamprey The Ohio lamprey (''Ichthyomyzon bdellium'') is a lamprey found in the Ohio River drainage basin in the United States and is a parasitic species of lampreys. They are considered to be an endangered/rare species in some states, due to siltati ...
) *''Ichthyomyzon castaneus'' Girard 1858 (
Chestnut lamprey The chestnut lamprey (''Ichthyomyzon castaneus'') is a species of lamprey. Description The chestnut lamprey has a maximum length of around , in Canada, with dark grey to olive skin color, blue-black after spawning, and with five to eight bic ...
) *''Ichthyomyzon fossor'' Reighard & Cummins 1916 ( Northern brook lamprey) *''Ichthyomyzon gagei'' Hubbs & Trautman 1937 (
Southern brook lamprey The southern brook lamprey (''Ichthyomyzon gagei'') is a lamprey found in the Southern United States including Arkansas, Louisiana, Mississippi, Alabama, and Georgia. It is a jawless fish with a sucking mouth on one end of it (like a leech). I ...
) *''Ichthyomyzon greeleyi'' Hubbs & Trautman 1937 (
Mountain brook lamprey The mountain brook lamprey or Allegheny brook lamprey (''Ichthyomyzon greeleyi'') is a lamprey found in parts of the Mississippi river basin, New York, Pennsylvania, Ohio, and in the Cumberland River and Tennessee River The Tennessee Riv ...
) *''Ichthyomyzon unicuspis'' Hubbs & Trautman 1937 (
Silver lamprey The silver lamprey (''Ichthyomyzon unicuspis'') is a lamprey commonly found in the Northern and Central United States, as well as a large part of southern Canada. Its binomial name means "sucking fish" in Greek and "one-pointed" in Latin. The ...
) *''Caspiomyzon wagneri'' (Kessler 1870) Berg 1906 (
Caspian lamprey The Caspian lamprey, ''Caspiomyzon wagneri'', is a species of lamprey native to the Caspian Sea, and a member of the Petromyzontidae family. ''Eudontomyzon hellenicus'' and '' E. graecus'' (if separate from ''E. hellenicus'') also possibly belong ...
) *''Caspiomyzon graecus'' (Renaud & Economidis 2010) (
Ionian brook lamprey Ionic or Ionian may refer to: Arts and entertainment * Ionic meter, a poetic metre in ancient Greek and Latin poetry * Ionian mode, a musical mode or a diatonic scale Places and peoples * Ionian, of or from Ionia, an ancient region in western ...
) *''Caspiomyzon hellenicus'' (Vladykov et al. 1982) (
Greek lamprey The Greek lamprey (''Caspiomyzon hellenicus'') (also known as the Greek brook lamprey) is a species of jawless fish in the Petromyzontidae family. It is endemic to Greece. Its natural habitats are rivers and freshwater springs. It is threatene ...
) *''Tetrapleurodon geminis'' Álvarez 1964 ( Mexican brook lamprey) *''Tetrapleurodon spadiceus'' (Bean 1887) ( Mexican lamprey) *''Entosphenus folletti'' Vladykov & Kott 1976 ( Northern California brook lamprey) *''Entosphenus lethophagus'' (Hubbs 1971) ( Pit-Klamath brook lamprey) *''Entosphenus macrostomus'' (Beamish 1982) ( Lake lamprey) *''Entosphenus minimus'' (Bond & Kan 1973) ( Miller Lake lamprey) *''Entosphenus similis'' Vladykov & Kott 1979 ( Klamath river lamprey) *''Entosphenus tridentatus'' (Richardson 1836) (
Pacific lamprey The Pacific lamprey (''Entosphenus tridentatus'') is an anadromous parasitic lamprey from the Pacific Coast of North America and Asia. It is a member of the Petromyzontidae family. The Pacific lamprey is also known as the three-tooth lamprey and ...
) *''Lethenteron alaskense'' Vladykov & Kott 1978 (
Alaskan brook lamprey Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U. ...
) *''Lethenteron appendix'' (DeKay 1842) (
American brook lamprey ''Lethenteron appendix'', the American brook lamprey, is a common non-parasitic lamprey in North America. In adults their disc-like mouths contain poorly developed teeth, useless for attaching to a host. Description The eggs of the American broo ...
) *''Lethenteron camtschaticum'' (Tilesius 1811) (
Arctic lamprey The Arctic lamprey (''Lethenteron camtschaticum''), also known as the Japanese river lamprey or Japanese lampern (''Petromyzon japonicus'' Martens 1868, ''Lampetra fluviatilis japonica'' (Martens 1868), '' Lampetra japonica'' (Martens 1868), '' L ...
) *''Lethenteron kessleri'' (Anikin 1905) ( Siberian brook lamprey) *''Lethenteron ninae'' Naseka, Tuniyev & Renaud 2009 ( Western Transcaucasian lamprey) *''Lethenteron reissneri'' (Dybowski 1869) (
Far Eastern brook lamprey ''Lethenteron reissneri'', the Far Eastern brook lamprey, is a species of non-parasitic lamprey Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , place ...
) *''Lethenteron zanandreai'' (Vladykov 1955) ( Lombardy lamprey) *''Eudontomyzon stankokaramani'' (Karaman 1974) ( Drin brook lamprey) *''Eudontomyzon morii'' (Berg 1931) ( Korean lamprey) *''Eudontomyzon danfordi'' Regan 1911 (
Carpathian brook lamprey ''Eudontomyzon danfordi'', the Carpathian brook lamprey or Danube lamprey, is a species of lamprey in the family Petromyzontidae. It is found in Austria, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Hungary, Moldova, Romania, ...
) *''Eudontomyzon mariae'' (Berg 1931) (
Ukrainian brook lamprey The Ukrainian brook lamprey (''Eudontomyzon mariae'') is a species of lamprey in the Petromyzontidae family. It is found in brackish and freshwater areas in Austria, Belarus, Bulgaria, the Czech Republic, Georgia, Hungary, Moldova, North Mace ...
) *''Eudontomyzon vladykovi'' (Oliva & Zanandrea 1959) ( Vladykov's lamprey) *''Lampetra aepyptera'' (Abbott 1860) ( Least brook lamprey) *''Lampetra alavariensis'' Mateus et al. 2013 ( Portuguese lamprey) *''Lampetra auremensis'' Mateus et al. 2013 ( Qurem lamprey) *''Lampetra ayresi'' (Günther 1870) ( Western river lamprey) *''Lampetra fluviatilis'' (Linnaeus 1758) ( European river lamprey) *''Lampetra hubbsi'' (Vladykov & Kott 1976) (
Kern brook lamprey The Kern brook lamprey (''Lampetra hubbsi'') is a species of lamprey in the Petromyzontidae family endemic to the United States. It is found on the east side of San Joaquin Valley, in lower Merced, Kaweah, Kings, and San Joaquin rivers in Cali ...
) *''Lampetra lanceolata'' Kux & Steiner 1972 ( Turkish brook lamprey) *''Lampetra lusitanica'' Mateus et al. 2013 (
lusitanic lamprey Lusitanic is a term used to refer to people who share the linguistic and cultural traditions of the Portuguese-speaking nations, territories, and populations, including Portugal, Brazil, Madeira, Macau, Timor-Leste, Azores, Angola, Mozambique ...
) *''Lampetra pacifica'' Vladykov 1973 ( Pacific brook lamprey) *''Lampetra planeri'' (Bloch 1784) ( European brook lamprey) *''Lampetra richardsoni'' Vladykov & Follett 1965 ( Western brook lamprey) *''Entosphenus macrostomus'' Dr. Dick Beamish 1980 ( Cowichan lake lamprey)


Lamprey and chordate synapomorphies

Synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ha ...
are certain characteristics that are shared over evolutionary history. Organisms possessing a
notochord In anatomy, the notochord is a flexible rod which is similar in structure to the stiffer cartilage. If a species has a notochord at any stage of its life cycle (along with 4 other features), it is, by definition, a chordate. The notochord consi ...
, dorsal hollow nerve cord, pharyngeal slits,
pituitary gland In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The h ...
/
endostyle The endostyle is an anatomical feature found in invertebrate chordates and larval lampreys. It is an organ which assists chordates in filter-feeding. It is found in adult urochordates and cephalochordates, as well as in the larvae of the vertebra ...
, and a post anal tail during the process of their development are considered to be
Chordate A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fi ...
s. Lampreys contain these characteristics that define them as chordates. Lamprey anatomy is very different based on what stage of development they are in. The
notochord In anatomy, the notochord is a flexible rod which is similar in structure to the stiffer cartilage. If a species has a notochord at any stage of its life cycle (along with 4 other features), it is, by definition, a chordate. The notochord consi ...
is derived from the
mesoderm The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical Emb ...
and is one of the defining characteristics of a chordate. The notochord provides signaling and mechanical cues to help the organism when swimming. The dorsal nerve cord is another characteristic of lampreys that defines them as chordates. During development this part of the ectoderm rolls creating a hollow tube. This is often why it is referred to as the dorsal "hollow" nerve cord. The third Chordate feature, which are the pharyngeal slits, are openings found between the pharynx or throat. Pharyngeal slits are filter feeding organs that help the movement of water through the mouth and out of these slits when feeing. During the lamprey's larval stage they rely on filter feeding as a mechanism for obtaining their food. Once lampreys reach their adult phase they become
parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...
on other fish, and these
gill slit Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In co ...
s become very important in aiding in the respiration of the organism. The final Chordate synapomorphy is the post anal tail which is a muscular tail that extends behind the anus. Oftentimes adult amphioxus and lamprey larvae are compared by anatomists due to their similarities. Similarities between adult amphioxus and lamprey larvae include a pharynx with pharyngeal slits, a notochord, a dorsal hollow nerve cord and a series of
somite The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryonic stage of somitogenesis, along the head-to-tail axis in segmented animals. In vertebrates, somites subdivide ...
s that extend anterior to the otic vesicle.


Fossil record

Lamprey
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s are rare because
cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck ...
fossilizes less readily than
bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
. The first fossil lampreys were originally found in Early
Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferou ...
limestones, marine sediments in North America: '' Mayomyzon pieckoensis'' and '' Hardistiella montanensis'', from the Mississippian
Mazon Creek The Mazon Creek fossil beds are a conservation ' found near Morris, in Grundy County, Illinois. The fossils are preserved in ironstone concretions, formed approximately in the mid- Pennsylvanian epoch of the Carboniferous period. These concretio ...
''
lagerstätte A Lagerstätte (, from '' Lager'' 'storage, lair' '' Stätte'' 'place'; plural ''Lagerstätten'') is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These f ...
'' and the Bear Gulch Limestone sequence. None of the fossil lampreys found to date have been longer than , and all the Paleozoic forms have been found in marine deposits. In the 22 June 2006 issue of ''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
'', Mee-mann Chang and colleagues reported on a fossil lamprey from the Yixian Formation of
Inner Mongolia Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an autonomous region of the People's Republic of China. Its border includes most of the length of China's border with the country of Mongolia. Inner Mongolia also accounts for a ...
. The new species, morphologically similar to Carboniferous and other forms, was given the name ''
Mesomyzon mengae ''Mesomyzon mengae'' is an extinct lamprey from freshwater strata of the Early Cretaceous-aged Yixian Formation, in China. So far, ''M. mengae'' is the only lamprey known from post-Paleozoic fossils. The animal's exquisitely preserved fossils ...
'' (" Meng Qingwen's Mesozoic lamprey"). The exceedingly well-preserved fossil showed a well-developed sucking oral disk, a relatively long branchial apparatus showing a branchial basket, seven gill pouches, gill arches, and even the impressions of gill filaments, and about 80 myomeres of its musculature. Unlike the North American fossils, its
habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
was almost certainly fresh water. Months later, a fossil lamprey even older than the Mazon Creek genera was reported from
Witteberg Group The Witteberg or Witteberge is a South African mountain range just off the south-west corner of Lesotho. The range, which rises to 2408 metres, stretches for about 60 km from Lundin's Neck in the east to Lady Grey in the west. The range l ...
rocks near
Grahamstown Makhanda, also known as Grahamstown, is a town of about 140,000 people in the Eastern Cape province of South Africa. It is situated about northeast of Port Elizabeth and southwest of East London. Makhanda is the largest town in the Makana ...
, in the
Eastern Cape The Eastern Cape is one of the provinces of South Africa. Its capital is Bhisho, but its two largest cities are East London and Gqeberha. The second largest province in the country (at 168,966 km2) after Northern Cape, it was formed in ...
of South Africa. Dating back 360 Million years, this species, ''
Priscomyzon riniensis ''Priscomyzon riniensis'' is an extinct lamprey that lived some 360 million years ago during the Famennian (Late Devonian) in a marine or estuarine environment in South Africa. This small agnathan is anatomically similar to the Mazon Creek la ...
'', is very similar to lampreys found today. 310 to 360 million years old fossils of P. riniensis hatchlings indicate that the ammocoete larva is a more recent evolutionary trait among the lampreys. The hatchlings, measuring 15mm in length, still had their
yolk sac The yolk sac is a membranous wikt:sac, sac attached to an embryo, formed by cells of the hypoblast layer of the bilaminar embryonic disc. This is alternatively called the umbilical vesicle by the Terminologia Embryologica (TE), though ''yolk sac' ...
, but were found in marine sediments and already had large eyes and a toothed suction disk.


Use in research

The lamprey has been extensively studied because its relatively simple brain is thought in many respects to reflect the brain structure of early vertebrate ancestors. Beginning in the 1970s, Sten Grillner and his colleagues at the
Karolinska Institute The Karolinska Institute (KI; sv, Karolinska Institutet; sometimes known as the (Royal) Caroline Institute in English) is a research-led medical university in Solna within the Stockholm urban area of Sweden. The Karolinska Institute is consist ...
in Stockholm followed on from extensive work on the lamprey started by Carl Rovainen in the 1960s that used the lamprey as a model system to work out the fundamental principles of motor control in vertebrates starting in the spinal cord and working toward the brain. In a series of studies by Rovainen and his student James Buchanan, the cells that formed the neural circuits within the spinal cord capable of generating the rhythmic motor patterns that underlie swimming were examined. Note that there are still missing details in the network scheme despite claims by Grillner that the network is characterised (Parker 2006, 2010). Spinal cord circuits are controlled by specific locomotor areas in the brainstem and midbrain, and these areas are in turn controlled by higher brain structures, including the basal ganglia and
tectum The midbrain or mesencephalon is the forward-most portion of the brainstem and is associated with vision, hearing, motor control, sleep and wakefulness, arousal ( alertness), and temperature regulation. The name comes from the Greek ''mesos'', " ...
. In a study of the lamprey tectum published in 2007, they found electrical stimulation could elicit eye movements, lateral bending movements, or swimming activity, and the type, amplitude, and direction of movement varied as a function of the location within the tectum that was stimulated. These findings were interpreted as consistent with the idea that the tectum generates goal-directed locomotion in the lamprey. Lampreys are used as a
model organism A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...
in biomedical research, where their large reticulospinal
axon An axon (from Greek ἄξων ''áxōn'', axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action p ...
s are used to investigate
synaptic transmission Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron ...
. The axons of lamprey are particularly large and allow for microinjection of substances for experimental manipulation. They are also capable of full functional recovery after complete spinal cord transection. Another trait is the ability to delete several genes from their
somatic cell A somatic cell (from Ancient Greek σῶμα ''sôma'', meaning "body"), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Such cells com ...
lineages, about 20% of their DNA, which are vital during development of the embryo, but which in humans can cause problems such as cancer later in life, after they have served their purpose. How the genes destined for deletion are targeted is not yet known.


In human culture


As food

Lampreys have long been used as food for humans. They were highly appreciated by the
ancient Romans In modern historiography, ancient Rome refers to Roman civilisation from the founding of the city of Rome in the 8th century BC to the collapse of the Western Roman Empire in the 5th century AD. It encompasses the Roman Kingdom (753–50 ...
. During the
Middle Ages In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire ...
they were widely eaten by the upper classes throughout Europe, especially during
Lent Lent ( la, Quadragesima, 'Fortieth') is a solemn religious moveable feast#Lent, observance in the liturgical calendar commemorating the 40 days Jesus spent fasting in the desert and enduring Temptation of Jesus, temptation by Satan, according ...
, when eating meat was prohibited, due to their meaty taste and texture. King
Henry I of England Henry I (c. 1068 – 1 December 1135), also known as Henry Beauclerc, was King of England from 1100 to his death in 1135. He was the fourth son of William the Conqueror and was educated in Latin and the liberal arts. On William's death in ...
is claimed to have been so fond of lampreys that he often ate them late into life and poor health against the advice of his physician concerning their richness, and is said to have died from eating "a
surfeit Surfeit is a human gene cluster that consists of a group of very tightly linked genes on chromosome 9 that do not share sequence similarity. Genes in this cluster are numbered 1 through 6: SURF1, SURF2, SURF3, SURF4 Surfeit locus protein 4 o ...
of lampreys". Whether or not his lamprey indulgence actually caused his death is unclear. The pie made for the coronation of
Elizabeth II of the United Kingdom Elizabeth II (Elizabeth Alexandra Mary; 21 April 1926 – 8 September 2022) was Queen of the United Kingdom and other Commonwealth realms from 6 February 1952 until her death in 2022. She was queen regnant of 32 sovereign states during ...
on 4 March 1953 was a lamprey pie. However, after many decades, the city of Gloucester had to use
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
lampreys for her Diamond Jubilee in 2012 because few lampreys could be found in the
River Severn , name_etymology = , image = SevernFromCastleCB.JPG , image_size = 288 , image_caption = The river seen from Shrewsbury Castle , map = RiverSevernMap.jpg , map_size = 288 , map_c ...
. In southwestern Europe (
Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of th ...
,
Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...
, and
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
),
Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bot ...
and in
Latvia Latvia ( or ; lv, Latvija ; ltg, Latveja; liv, Leţmō), officially the Republic of Latvia ( lv, Latvijas Republika, links=no, ltg, Latvejas Republika, links=no, liv, Leţmō Vabāmō, links=no), is a country in the Baltic region of ...
(where lamprey is routinely sold in supermarkets), lampreys are a highly prized
delicacy A delicacy is usually a rare and expensive food item that is considered highly desirable, sophisticated, or peculiarly distinctive within a given culture. Irrespective of local preferences, such a label is typically pervasive throughout a r ...
. In Finland (county of Nakkila), and Latvia (
Carnikava Municipality Carnikava Municipality ( lv, Carnikavas novads) is a former municipality in Vidzeme, Latvia. The municipality was formed in 2006 by reorganization of Carnikava Parish of the Riga District, with the administrative centre being Carnikava. The po ...
), the river lamprey is the local symbol, found on their coats of arms. In 2015 the lamprey from Carnikava was included in the
Protected designation of origin The protected designation of origin (PDO) is a type of geographical indication of the European Union and the United Kingdom aimed at preserving the designations of origin of food-related products. The designation was created in 1992 and its main ...
list by the
European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body ...
.
Sea lamprey The sea lamprey (''Petromyzon marinus'') is a parasitic lamprey native to the Northern Hemisphere. It is sometimes referred to as the "vampire fish". Description The sea lamprey has an eel-like body without paired fins. Its mouth is jawless, ...
is the most sought-after species in
Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of th ...
and one of only two that can legally bear the commercial name "lamprey" (''lampreia''): the other one being ''Lampetra fluviatilis'', the European river lamprey, both according to Portaria (Government regulation no. 587/2006, from 22 June). "Arroz de lampreia" or lamprey rice is one of the most important dishes in
Portuguese cuisine The oldest known book on Portuguese cuisine, entitled ''Livro de Cozinha da Infanta D. Maria de Portugal'', from the 16th century, describes many popular dishes of meat, fish, poultry and others. ''Culinária Portuguesa'', by António-Maria De O ...
. Lampreys are also consumed in
Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic countries, Nordic c ...
,
Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...
,
Lithuania Lithuania (; lt, Lietuva ), officially the Republic of Lithuania ( lt, Lietuvos Respublika, links=no ), is a country in the Baltic region of Europe. It is one of three Baltic states and lies on the eastern shore of the Baltic Sea. Lithuania ...
,
Estonia Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, an ...
,
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...
, and
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
. In Finland, they are commonly eaten grilled or smoked, but also pickled, or in vinegar. The
mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It ...
and
serum Serum may refer to: * Serum (blood), plasma from which the clotting proteins have been removed **Antiserum, blood serum with specific antibodies for passive immunity * Serous fluid, any clear bodily fluid *Truth serum, a drug that is likely to mak ...
of several lamprey species, including the
Caspian lamprey The Caspian lamprey, ''Caspiomyzon wagneri'', is a species of lamprey native to the Caspian Sea, and a member of the Petromyzontidae family. ''Eudontomyzon hellenicus'' and '' E. graecus'' (if separate from ''E. hellenicus'') also possibly belong ...
(''Caspiomyzon wagneri''), river lampreys (''Lampetra fluviatilis'' and ''L. planeri''), and sea lamprey (''Petromyzon marinus''), are known to be toxic, and require thorough cleaning before cooking and consumption. In Britain, lampreys are commonly used as
bait Bait may refer to: General * Bait (luring substance), bait as a luring substance ** Fishing bait, bait used for fishing Film * ''Bait'' (1950 film), a British crime film by Frank Richardson * ''Bait'' (1954 film), an American noir film by Hugo ...
, normally as dead bait.
Northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (the pikes). They are typical of brackish water, brackish and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). They are kno ...
,
perch Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Per ...
, and
chub Chub is a common fish name. It pertains to any one of a number of ray-finned fish in several families and genera. In the UK, the term ''chub'' usually refers to the species '' Squalius cephalus''. In addition, see sea chub. In family Cyprinida ...
all can be caught on lampreys. Frozen lampreys can be bought from most bait and tackle shops.


As pests

Sea lampreys have become a major pest in the North American
Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
. It is generally believed that they gained access to the lakes via
canals Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface flow un ...
during the early 20th century, but this theory is controversial. They are considered an
invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...
, have no natural enemies in the lakes, and prey on many species of commercial value, such as
lake trout The lake trout (''Salvelinus namaycush'') is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, namaycush, lake char (or charr), touladi, togue, and grey trout. In Lake Superior, it can also ...
. Lampreys are now found mostly in the streams that feed the lakes, and controlled 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, these 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 sterilized male lampreys in a method akin to the sterile insect technique. Finally, pheromones critical to lamprey migratory behaviour have been isolated, their
chemical structure A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of ...
s determined, and their impact on lamprey behaviour studied, in the laboratory and in the wild, and active efforts are underway to chemically source and to address regulatory considerations that might allow this strategy to proceed. Control of sea lampreys in the Great Lakes is conducted by the U.S. Fish and Wildlife Service and the Canadian Department of Fisheries and Oceans, and is coordinated by the Great Lakes Fishery Commission.
Lake Champlain , native_name_lang = , image = Champlainmap.svg , caption = Lake Champlain-River Richelieu watershed , image_bathymetry = , caption_bathymetry = , location = New York/ Vermont in the United States; and Quebec in Canada , coords = , type ...
, bordered by
New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...
,
Vermont Vermont () is a U.S. state, state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York (state), New York to the west, and the Provin ...
, and
Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirte ...
, and New York's Finger Lakes are also home to high populations of sea lampreys that warrant control. Lake Champlain's lamprey control program is managed by the
New York State Department of Environmental Conservation The New York State Department of Environmental Conservation (informally referred to as NYSDEC, DEC, EnCon or NYSENCON) is a department of New York state government. The department guides and regulates the conservation, improvement, and protection ...
, 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.


In folklore

In folklore, lampreys are called "nine-eyed eels". The name is derived from the seven external gill slits that, along with one nostril and one eye, line each side of a lamprey's head section. Likewise, the German word for lamprey is ''Neunauge'', which means "nine-eye", and in Japanese they are called ''yatsume-unagi'' (八つ目鰻, "eight-eyed eels"), which excludes the nostril from the count. In British folklore, the monster known as the Lambton Worm may have been based on a lamprey, since it is described as an eel-like creature with nine eyes.


In literature

Vedius Pollio kept a pool of lampreys into which
slaves Slavery and enslavement are both the state and the condition of being a slave—someone forbidden to quit one's service for an enslaver, and who is treated by the enslaver as property. Slavery typically involves slaves being made to perf ...
who incurred his displeasure would be thrown as food. On one occasion, Vedius was punished by
Augustus Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian, was the first Roman emperor; he reigned from 27 BC until his death in AD 14. He is known for being the founder of the Roman Pr ...
for attempting to do so in his presence: This incident was incorporated into the plot of the 2003 novel ''Pompeii'' by Robert Harris in the incident of Ampliatus feeding a slave to his lampreys.
Lucius Licinius Crassus Lucius Licinius Crassus (140–91 BC) was a Roman orator and statesman. He was considered the greatest orator of his day, most notably by his pupil Cicero. Crassus is also famous as one of the main characters in Cicero's work '' De Oratore'', a ...
was mocked by Gnaeus Domitius Ahenobarbus (cos. 54 BC) for weeping over the death of his pet lamprey: This story is also found in Aelian (Various Histories VII, 4) and Macrobius (Saturnalia III.15.3). It is included by
Hugo von Hofmannsthal Hugo Laurenz August Hofmann von Hofmannsthal (; 1 February 1874 – 15 July 1929) was an Austrian novelist, librettist, poet, dramatist, narrator, and essayist. Early life Hofmannsthal was born in Landstraße, Vienna, the son of an upper-cl ...
in the Chandos Letter: In George R. R. Martin's novel series, ''
A Song of Ice and Fire ''A Song of Ice and Fire'' is a series of epic fantasy novels by the American novelist and screenwriter George R. R. Martin. He began the first volume of the series, '' A Game of Thrones'', in 1991, and it was published in 1996. Martin, who i ...
'', Lord Wyman Manderly is mockingly called "Lord Lamprey" by his enemies in reference to his rumored affinity to lamprey pie and his striking
obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...
. Kurt Vonnegut, in his late short story " The Big Space Fuck", posits a future America so heavily polluted – "Everything had turned to shit and beer cans", in his words – that the Great Lakes have been infested with a species of massive, man-eating ambulatory lampreys.


In television

In season 3, episode 5 of “The Borgias”, whilst out on a hunting trip, Cesare Borgia’s mercenary, Micheletto, kills the King of Naples by pushing him into a pool filled with lampreys that King Firante had built during his reign of Naples.


References


Further reading


General

* Renaud, C.B. (2011) ''Lampreys of the world. An annotated and illustrated catalogue of lamprey species known to date'' FAO Species Catalogue for Fishery Purposes. No. 5. Rome. .


Research on pheromones for pest control

* , se
Mixture of new sulfated steroids functions as a migratory pheromone in the sea lamprey
accessed 1 July 2015. rimary source example.* , se
Chemical cues for sea lamprey migration
accessed 1 July 2015. ay summary of Sorensen, et al. (2005)* rimary source example.* Richard Black, 2009, "Sex smell lures 'vampire' to doom," ''BBC News'' (online), 20 January 2009, se
Sex smell lures 'vampire' to doom
accessed 1 July 2015. ay summary of Johnson, et al. (2009); Subtitle: "A synthetic 'chemical sex smell' could help rid North America's Great Lakes of a devastating pest, scientists say."


External links

* * *
Long-accepted theory of vertebrate origin upended by fossilized lamprey larvae
* A Tree of Life diagram showing the relation of Lampreys to other organisms. {{Authority control . Hematophages Parasitic vertebrates Devonian fish Extant Late Devonian first appearances Fish described in 1940