Larus

Taxobox
name = "Larus"

---

image_width = 250px
image_caption = Herring Gull
regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Charadriiformes
familia = Laridae
genus = "Larus"
genus_authority = Linnaeus, 1758
subdivision_ranks = Species
subdivision = "See list"

"Larus" is a large genus of gulls with worldwide distribution (although by far the greatest species diversity in the Northern Hemisphere). Many of its species are abundant and well-known birds in their ranges. Until recently, 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 the head 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, different authorities recognising between two and eight species. "See also" Hybridisation in gulls.

ystematics and evolution

List of species

*Pacific Gull, "Larus pacificus"
*Belcher's Gull, "Larus belcheri"
*Olrog's Gull, "Larus atlanticus"
*Black-tailed Gull, "Larus crassirostris"
*Heermann's Gull, "Larus heermanni"
*Common Gull or Mew Gull, "Larus canus"
*Ring-billed Gull, "Larus delawarensis"
*California Gull, "Larus californicus"
*Great Black-backed Gull, "Larus marinus"
*Kelp Gull, "Larus dominicanus" (called "Southern Black-backed Gull" or "Karoro" in New Zealand)
** Cape Gull, "Larus dominicanus vetula"
*Glaucous-winged Gull, "Larus glaucescens"
*Western Gull, "Larus occidentalis"
*Yellow-footed Gull, "Larus livens"
*Glaucous Gull, "Larus hyperboreus"
*Iceland Gull, "Larus glaucoides"
** Kumlien's Gull, "Larus glaucoides kumlieni"
*Thayer's Gull, "Larus thayeri"
*Herring Gull, "Larus argentatus"
*Heuglin's Gull, "Larus heuglini"
*American Herring Gull, "Larus smithsonianus"
*Yellow-legged Gull, "Larus michahellis"
*Caspian Gull, "Larus cachinnans"
*East Siberian Herring Gull, "Larus vegae"
**Birula's Gull, "Larus vegae birulai"
*Armenian Gull, "Larus armenicus"
*Slaty-backed Gull, "Larus schistisagus"
*Lesser Black-backed Gull, "Larus fuscus"
*Saunders' Gull, "Larus saundersi"

Fossils of "Larus" gulls are known since the Middle Miocene, c.20-15 mya; allocation of earlier fossils to this genus is generally rejected nowadays (see below). 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" sp. (Grund Middle Miocene of Austria)
*"Larus" sp. (Middle Miocene of Romania) (Olson, 1985)
*"Larus" sp. (Late? Miocene/Early Pliocene of Lee Creek Mine, USA) - several species (Olson, 1985)
*"Larus elmorei" (Bone Valley Early/Middle Pliocene of SE USA)
*"Larus lacus" (Pinecrest Late Pliocene of SE USA)
*"Larus perpetuus" (Pinecrest Late Pliocene of SE USA)
*"Larus" sp. (San Diego Late Pliocene of SW USA)
*"Larus oregonus" (Late Pliocene - Late Pleistocene of WC USA)
*"Larus robustus" (Late Pliocene - Late Pleistocene of WC USA)
*"Larus" sp. (Lake Manix Late Pleistocene of W USA)

"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 SE France) are now in "Laricola", while "L." dolnicensis" (Early Miocene of Czechia) was actually a pratincole; it is now placed in "Mioglareola".

The Early Miocene "Larus" desnoyersii" (SE France) and "L." pristinus" (John Day Formation, Willow Creek, USA) probably do not belong in this genus; the former may be a skua (Olson, 1985).

Ring species

A classic example of ring species is the "Larus" gulls circumpolar species "ring". The range of these gulls forms a ring around the North Pole. The Herring Gull, which lives primarily in Great Britain, can hybridize with the American Herring Gull (living in North America), which can also interbreed with the Vega or East Siberian Herring 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). 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 cannot 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 likely does not constitute a ring-species (Liebers "et al", 2004).

References

* Harrison, Peter (1988): "Seabirds" (2nd ed.). Christopher Helm, London ISBN 0-7470-1410-8

* Liebers, Dorit; de Knijff, Peter & Helbig, Andreas J. (2004): The herring gull complex is not a ring species. "Proc. Roy. Soc. B" 271(1542): 893-901. DOI|10.1098/rspb.2004.2679 [http://www.journals.royalsoc.ac.uk/(ck042z55y2a4k2jegtv51r45)/app/home/content.asp?referrer=contribution&format=2&page=1&pagecount=9 PDF fulltext] [http://www.journals.royalsoc.ac.uk/media/public/contributionsupplementalmaterials/v/y/h/e/vyhea7ddp48gn5a1/archive1.pdf Electronic Appendix]

* Olson, Storrs L. (1985): Section X.D.2.j. Laridae. "In:" Farner, D.S.; King, J.R. & Parkes, Kenneth C. (eds.): "Avian Biology" 8: 181-182. Academic Press, New York.

* Pons J.-M. ; Hassanin A. ; Crochet P.-A.(2005) Phylogenetic relationships within the Laridae (Charadriiformes: Aves) inferred from mitochondrial markers. Molecular phylogenetics and evolution 37(3):686-699.