''Larus'' is a large

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of gulls with worldwide distribution (by far the greatest species diversity is in the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

). Many of its species are abundant and well-known birds in their ranges. Until about 2005–2007, most gulls were placed in this genus, but this arrangement is now known to be

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

, leading to the resurrection of the genera '' Chroicocephalus'', '' Ichthyaetus'', '' Hydrocoloeus'', and ''

Leucophaeus ''Leucophaeus'' is a small genus of medium-sized New World gulls, most of which are dark in plumage, usually with white crescents above and below the eyes. They were placed in the genus ''Larus'' until recently. The genus name ''Leucophaeus'' is ...

'' for many other species formerly included in ''Larus''. They are in general medium-large birds, typically pale grey to black above and white below and on the head, often with black markings with white spots ("mirrors") on their wingtips and in a few species also some black on the tail. They have stout, longish bills and webbed feet; in winter, the head is often streaked or smudged dark grey. The young birds are brown, and take three to five years to reach adult plumage, with subadult plumages intermediate between the young and adult. The taxonomy of the large gulls in the herring and lesser black-backed complex is complicated, with different authorities recognising from two species in the past, increasingly up to eight species more recently.

Taxonomy

The

''Larus'' was introduced in 1758 by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in the tenth edition of his ''

Systema Naturae ' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...

''. The genus name is from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

''laros'' (λάῥος) or

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''larus'', which appears to have referred to a gull or other large seabird. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is the

great black-backed gull The great black-backed gull (''Larus marinus'') is the largest member of the gull family. It is a very aggressive hunter, pirate, and scavenger which breeds on the coasts and islands of the North Atlantic in northern Europe and northeastern Nort ...

(''Larus marinus''). The Latin name ''Larus marinus'' translates as "sea gull", and the gulls in this genus generally are the species most often known colloquially as "seagulls".

Species

The genus contains 25 extant species.

Fossils

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 preserve ...

s of ''Larus'' gulls are known from the

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0. ...

, about 20-15 million years ago; allocation of earlier fossils to this genus is generally rejected. Biogeography of the fossil record suggests that the genus evolved in the northern Atlantic and spread globally during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Lee Creek Mine, U.S.) - several species *'' Larus elmorei'' (Middle Pliocene of Bone Valley, southeastern U.S.) *'' Larus lacus'' (Late Pliocene of Pinecrest, southeastern U.S.) *'' Larus perpetuus'' (Pliocene of southeastern U.S.) *''Larus'' sp. (San Diego Late Pliocene of the southwestern U.S.) *'' Larus oregonus'' (Late Pliocene - Late Pleistocene of the west-central U.S.) *'' Larus robustus'' (Late Pliocene - Late Pleistocene of the west-central U.S.) *''Larus'' sp. (Late Pleistocene of Lake Manix western U.S.) ''"Larus" raemdonckii'' (Early Oligocene of Belgium) is now at least tentatively believed to belong in the procellariiform genus '' Puffinus''. ''"L." elegans'' (Late Oligocene?/Early Miocene of St-Gérand-le-Puy, France) and ''"L." totanoides'' (Late Oligocene?/Early Miocene of southeastern France) are now in '' Laricola'', while ''"L." dolnicensis'' (Early Miocene of the Czech Republic) was actually a pratincole; it is now placed in '' Mioglareola''. The Early Miocene ''"Larus" desnoyersii'' (southeastern France) and ''"L." pristinus'' (John Day Formation, Willow Creek, U.S.) probably do not belong in this genus; the former may be a skua.(Olson, 1985).

Ring species

The circumpolar group of ''Larus'' gull species has often been cited as a classic example of the

ring species In biology, a ring species is a connected series of neighbouring populations, each of which interbreeds with closely sited related populations, but for which there exist at least two "end populations" in the series, which are too distantly relate ...

. The range of these gulls forms a ring around the

North Pole The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where the Earth's rotation, Earth's axis of rotation meets its surface. It is called the True North Pole to distingu ...

. The European herring gull, which lives primarily in

Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...

and

Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe northern Europe as being roughly north of the southern coast of the Baltic Sea, which is about 54th parallel north, 54°N, or may be based on other ge ...

, can hybridize with the American herring gull (living in North America), which can also interbreed with the Vega or East Siberian gull, the western subspecies of which, Birula's gull, can hybridize with Heuglin's gull which, in turn, can interbreed with the Siberian lesser black-backed gull (all four of these live across the north of

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

). The last is the eastern representative of the lesser black-backed gulls back in northwestern Europe, including Great Britain. However, the lesser black-backed gulls and herring gull are sufficiently different that they rarely interbreed; thus, the group of gulls forms a continuum except in Europe, where the two lineages meet. However, a recent genetic study has shown that this example is far more complicated than presented here, and probably does not constitute a true ring species.Supplemental material: Electronic appendices
/ref>

References

{{Authority control Bird genera Taxa named by Carl Linnaeus

Taxonomy

Species

Fossils

Ring species

See also

References