Thymallus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 in the salmon

Salmon

Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

 family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 (family Salmonidae

Salmonidae

Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings...

) of order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Salmoniformes; it is the only genus of subfamily Thymallinae. The type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 is T. thymallus, the grayling

Grayling (species)

The grayling is a species of freshwater fish in the salmon family of order Salmoniformes. It is the type species of its genus. Native to the Palearctic ecozone, the grayling is widespread throughout northern Europe, from the United Kingdom and France to the Ural Mountains in Russia...

. The genus's five distinct species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 are generically called graylings, but without qualification this also refers specifically to T. thymallus.

The fishes of this genus are native to the northern parts of the Palearctic

Palearctic

The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...

 and Nearctic

Nearctic

The Nearctic is one of the eight terrestrial ecozones dividing the Earth's land surface.The Nearctic ecozone covers most of North America, including Greenland and the highlands of Mexico...

 ecozone

Ecozone

An ecozone is the broadest biogeographic division of the Earth's land surface, based on distributional patterns of terrestrial organisms.Ecozones delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from...

s, ranging from the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 and northern Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 across Eurasia

Eurasia

Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

 to Siberia

Siberia

Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

, as well as northern North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

. T. thymallus, the grayling proper, is widespread in Europe, and T. arcticus arcticus, the Arctic grayling, is widespread throughout Eurasia east of the Ural Mountains

Ural Mountains

The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...

 and in the Nearctic. The other species and T. arcticus subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 have more localized ranges.

The Thymallus species are distinguished from other members of the salmon

Salmon

Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...

 family by their larger scales, their small mouths with teeth on the maxillary

Maxilla

The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

 bone, and most striking of all, their showy, sail-like dorsal fin

Dorsal fin

A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

s. This fin is longer in males and highly colourful, with spots of red, orange, purple or green. The body is also colourful; the dorsal surface is a dark purplish to bluish black or gray, grading to dark blue or silver gray on the flanks and gray or white on the belly. The body is further decorated with a smattering of small dark spots; these are much more numerous in juveniles.
The largest of the graylings in terms of length is the Arctic grayling

Arctic grayling

Arctic grayling is a species of freshwater fish in the salmon family of order Salmoniformes. It comprises five subspecies native to the Nearctic and Palearctic ecozones. T. a. arcticus is widespread throughout the Arctic and Pacific drainages in Canada, Alaska, and Siberia, as well as the upper...

 (T. arcticus arcticus) at a maximum length of 76 cm

Centimetre

A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...

 (30 in) and a maximum weight of 3.8 kg

Kilogram

The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...

 (8.4 lb

Pound (mass)

The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

); other subspecies of T. arcticus are typically half this length or less. The grayling proper, T. thymallus, while somewhat shorter - 60 cm (24 in) - may weigh significantly more, 6.7 kg (15 lb).
The fishes of this genus may live for 18 years or more.

As they are highly sensitive to changes in water quality, Thymallus fishes may be considered indicator species

Indicator species

An indicator species is any biological species that defines a trait or characteristic of the environment. For example, a species may delineate an ecoregion or indicate an environmental condition such as a disease outbreak, pollution, species competition or climate change...

; T. arcticus arcticus has largely disappeared from the Great Lakes Basin

Great Lakes Basin

The Great Lakes Basin consists of the Great Lakes and the surrounding lands of the states of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin in the United States, and the province of Ontario in Canada, whose direct surface runoff and watersheds form a large...

. These fishes require cool, well-oxygenated water, preferably with a swift current; they are found in large sandy- or gravelly-bottomed rivers and lakes, but T. thymallus may occasionally be found in brackish conditions. Generally omnivorous, they feed primarily on crustaceans, insects, and zooplankton

Zooplankton

Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...

.

The grayling species, typically for salmonids

Salmonidae

Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings...

, spawn in rivers and do not guard their brood, although they do conceal their eggs in silt. The spawning behavior of the Arctic grayling

Arctic grayling

Arctic grayling is a species of freshwater fish in the salmon family of order Salmoniformes. It comprises five subspecies native to the Nearctic and Palearctic ecozones. T. a. arcticus is widespread throughout the Arctic and Pacific drainages in Canada, Alaska, and Siberia, as well as the upper...

 may be typical for the Thymallus species.

Due to their agreeable taste and attractive form, the grayling species are valued as food and game fishes, and they are occasionally seen in public aquaria

Aquaria

Aquaria may refer to:*Aquarium, in the plural*Aquaria , a computer game*Aquaria , a Brazilian metal band*Aquaria, one of the Twelve Colonies in Battlestar Galactica...

. The most economically important of these fishes, for which fisheries

Fishery

Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...

 and aquaculture

Aquaculture

Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...

 operations exist, are the grayling

Grayling (species)

The grayling is a species of freshwater fish in the salmon family of order Salmoniformes. It is the type species of its genus. Native to the Palearctic ecozone, the grayling is widespread throughout northern Europe, from the United Kingdom and France to the Ural Mountains in Russia...

 proper (T. thymallus) and the Arctic grayling

Arctic grayling

Arctic grayling is a species of freshwater fish in the salmon family of order Salmoniformes. It comprises five subspecies native to the Nearctic and Palearctic ecozones. T. a. arcticus is widespread throughout the Arctic and Pacific drainages in Canada, Alaska, and Siberia, as well as the upper...

 (T. arcticus arcticus).

Name

The generic name Thymallus derives from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 θύμαλλος,, "thyme

Thyme

Thyme is a culinary and medicinal herb of the genus Thymus.-History:Ancient Egyptians used thyme for embalming. The ancient Greeks used it in their baths and burnt it as incense in their temples, believing it was a source of courage...

 smell", a name derived from the fragrance of wild thyme that freshly caught graylings quite often have.

Franz Steindachner

Franz Steindachner

Franz Steindachner was an Austrian zoologist.- Work and career :Being interested in natural history, Steindachner took up the study of fossil fishes on the recommendation of his friend Eduard Suess...

 (1834–1919) classified the Adriatic trout

Adriatic trout

Salmo obtusirostris, also known as the Adriatic trout, Adriatic salmon, and softmouth trout, is a species of salmonid fish endemic to the rivers of Western Balkans in southeastern Europe...

 (Salmo obtusirostris) as Thymallus microlepis, but that name is not considered valid.

Species

• T. arcticus:
  • T. arcticus arcticus – Arctic grayling
  • T. arcticus baicalensis – Baikal black grayling
  • T. arcticus mertensii
  • T. arcticus pallasi – East Siberian grayling
• T. brevirostris – Mongolian grayling
• T. grubii – Amur grayling
• T. nigrescens – Kosogol grayling
• T. thymallus – Grayling
• T. tugarinae
• T. yaluensis
  Thymallus yaluensis
  Thymallus yaluensis is a species of freshwater fish in the salmon family of order Salmoniformes. The species has been reported in Korea, Siberia, the Alps in Europe, and the northern Mississippi River drainage in North America.T...