genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of
gull
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century ...
s with worldwide distribution (by far the greatest
species diversity
Species diversity is the number of different species that are represented in a given community (a dataset). The effective number of species refers to the number of equally abundant species needed to obtain the same mean proportional species abundan ...
is in the Northern Hemisphere).
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 of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...
, leading to the resurrection of the genera ''
Ichthyaetus
''Ichthyaetus'' is a genus of gulls. The genus name is from Ancient Greek ''ikhthus'', "fish", and ''aetos'', "eagle". They were previously included in the genus ''Larus''.Pons J.M., Hassanin, A., and Crochet P.A.(2005). ''Phylogenetic relationsh ...
'', ''
Chroicocephalus
''Chroicocephalus'' is a genus of medium to relatively small gulls which were included in the genus '' Larus'' until recently. Some authorities also include the Saunders's gull in ''Chroicocephalus''. The genus name '' Chroicocephalus'' is from ...
'', ''
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 ...
'', and '' Hydrocoloeus'' (this last had been recognized more often than the other genera) for several species traditionally included in ''Larus''.
They are in general medium to large birds, typically grey or white, often with black markings on their heads or wings. They have stout, longish
bill
Bill(s) may refer to:
Common meanings
* Banknote, paper cash (especially in the United States)
* Bill (law), a proposed law put before a legislature
* Invoice, commercial document issued by a seller to a buyer
* Bill, a bird or animal's beak
Plac ...
s and webbed feet.
The taxonomy of the large gulls in the herring and lesser black-backed complex is very complicated, with different authorities recognising between two and eight species.
Taxonomy
The
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''Larus'' was introduced in 1758 by the Swedish naturalist
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
''laros'' (λάῥος) or
Latin
Latin (, or , ) is a classical language belonging to the 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 the power of the ...
''larus'', which appears to have referred to a gull or other large seabird. The
type species
In 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 species that contains the biological type specime ...
is the
great black-backed gull
The great black-backed gull (''Larus marinus'') is the largest member of the gull family. Described by the Cornell Lab of Ornithology as "the king of the Atlantic waterfront", it is a very aggressive hunter, pirate, and scavenger. It breeds on t ...
(''Larus marinus'').
Species
The genus contains 24 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 preserved ...
s of ''Larus'' gulls are known from the Middle Miocene, 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
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...
and spread globally during the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Lee Creek Mine, U.S.) - several species
*''Larus elmorei'' (Early/Middle Pliocene of
Bone Valley
The Bone Valley is a region of central Florida, encompassing portions of present-day Hardee, Hillsborough, Manatee, and Polk counties, in which phosphate is mined for use in the production of agricultural fertilizer. Florida currently contains t ...
, southeastern U.S.)
*''Larus lacus'' ( Late Pliocene of Pinecrest, southeastern U.S.)
*''Larus perpetuus'' (Late Pliocene of Pinecrest, 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
Lake Manix is a former lake fed by the Mojave River in the Mojave Desert. It lies within San Bernardino County, California. Located close to Barstow, this lake had the shape of a cloverleaf and covered four basins named Coyote, Cady/Manix, Troy an ...
western U.S.)
''"Larus" raemdonckii'' (Early Oligocene of Belgium) is now at least tentatively believed to belong in the procellariiform genus ''
Puffinus
''Puffinus'' is a genus of seabirds in the order Procellariiformes that contains about 20 small to medium-sized shearwaters. Two other shearwater genera are named: '' Calonectris'', which comprises three or four large shearwaters, and '' Ardenna' ...
''. ''"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
The pratincoles or greywaders are a group of birds which together with the coursers make up the family Glareolidae. They have short legs, very long pointed wings and long forked tails.
Description
Their most unusual feature for birds classed a ...
; 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
The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are called ...
.(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
The European herring gull (''Larus argentatus'') is a large gull, up to long. One of the best-known of all gulls along the shores of Western Europe, it was once abundant. It breeds across Northern Europe, Western Europe, Central Europe, Eastern ...
, which lives primarily in
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It i ...
hybridize
Hybridization (or hybridisation) may refer to:
*Hybridization (biology), the process of combining different varieties of organisms to create a hybrid
*Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals
*Nu ...
with the
American herring gull
The American herring gull or Smithsonian gull (''Larus smithsonianus'' or ''Larus argentatus smithsonianus'') is a large gull that breeds in North America, where it is treated by the American Ornithological Society as a subspecies of herring gul ...
(living in North America), which can also interbreed with the
Vega
Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, a ...
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 ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
). The last is the eastern representative of the
lesser black-backed gull
The lesser black-backed gull (''Larus fuscus'') is a large gull that breeds on the Atlantic coasts of Europe. It is migratory, wintering from the British Isles south to West Africa. It has increased dramatically in North America, most common alo ...
s 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>