Larus


Larus is a large genus of gulls with worldwide distribution. The genus name is from Ancient Greek laros or Latin larus, which appears to have referred to a gull or other large seabird.
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, leading to the resurrection of the genera Ichthyaetus, Chroicocephalus, Leucophaeus, and Hydrocoloeus 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 bills 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.

Systematics and evolution

List of species in taxonomic order

Fossils 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 nowadays. Biogeography of the fossil record suggests that the genus evolved in the northern Atlantic and spread globally during the Pliocene, when species diversity seems to have been highest, as with most seabirds.
"Larus" raemdonckii is now at least tentatively believed to belong in the procellariiform genus Puffinus. "L." elegans and "L." totanoides are now in Laricola, while "L." dolnicensis was actually a pratincole; it is now placed in Mioglareola.
The Early Miocene "Larus" desnoyersii and "L." pristinus probably do not belong in this genus; the former may be a skua.

Ring species

The circumpolar group of Larus gull species has often been cited as a classic example of the ring species. The range of these gulls forms a ring around the North Pole. The European herring gull, which lives primarily in Great Britain, can hybridize with the American herring gull, 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. 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.