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''Larus'' is a large genus of gulls with worldwide distribution (although by far the greatest species diversity 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, leading to the resurrection of the genera ''Ichthyaetus'', ''Chroicocephalus'', ''Leucophaeus'', 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 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'' Hybridisation in gulls. ==Systematics 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'' *American herring gull, ''Larus smithsonianus'' *Yellow-legged gull, ''Larus michahellis'' *Caspian gull, ''Larus cachinnans'' *East Siberian gull, ''Larus vegae'' (or Vega Gull) * *Birula's gull, ''Larus vegae birulai'' *Armenian gull, ''Larus armenicus'' *Slaty-backed gull, ''Larus schistisagus'' *Lesser black-backed gull, ''Larus fuscus'' *Heuglin's gull, ''Larus (fuscus) heuglini'' 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 Czech Republic) 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). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Larus」の詳細全文を読む スポンサード リンク
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