Laridae

Laridae is a family of seabirds in the order Charadriiformes that includes the gulls, terns and skimmers. It includes around 100 species arranged into 22 genera. They are an adaptable group of mostly aerial birds found worldwide.

Taxonomy
The family Laridae was introduced (as Laridia) by the French polymath Constantine Samuel Rafinesque in 1815. Historically, Laridae were restricted to the gulls, while the terns were placed in a separate family, Sternidae, and the skimmers in a third family, Rynchopidae. The noddies were traditionally included in Sternidae. In 1990 Charles Sibley and Jon Ahlquist included auks and skuas in a broader family Laridae.

A molecular phylogenetic study by Baker and colleagues published in 2007 found that the noddies in the genus Anous formed a sister group to a clade containing the gulls, skimmers and the other terns. To create a monophyletic family group, Laridae was expanded to include the genera that had previously been in Sternidae and Rynchopidae.

Baker and colleagues found that the Laridae lineage diverged from a lineage that gave rise to both the skuas (Stercorariidae) and auks (Alcidae) before the end of the Cretaceous in the age of dinosaurs. They also found that the Laridae themselves began expanding in the early Paleocene, around 60 million years ago. The German palaeontologist Gerald Mayr has questioned the validity of these early dates and suggested that inappropriate fossils were used in calibrating the molecular data. The earliest charadriiform fossils date only from the late Eocene, around 35 million years ago.

Anders Ödeen and colleagues investigated the development of ultraviolet vision in shorebirds, by looking for the SWS1 opsin gene in various species; as gulls were the only shorebirds known to have developed the trait. They discovered that the gene was present in the gull, skimmer and noddy lineages but not the tern lineage. They also recovered the noddies as an early lineage, though the evidence was not strong.

The genera are listed in taxonomic order.

Genus Gygis
(1 or 2 species) (White Tern)
 * White Tern, Gygis alba
 * Little White-Tern, Gygis (alba) microrhyncha

Genus Rynchops
(3 species)
 * Black Skimmer, ''Rynchops niger
 * African Skimmer, Rynchops flavirostris
 * Indian Skimmer, Rynchops albicollis

Genus Anous
(5 species)
 * Brown Noddy or Common Noddy, Anous stolidus
 * Black Noddy, Anous minutus
 * Lesser Noddy, Anous tenuirostris
 * Blue-grey Noddy / Blue Noddy, Anous cerulea
 * Grey Noddy, Anous albivitta

Genus Gelochelidon
(2 species)
 * Gull-billed Tern, Gelochelidon nilotica
 * Australian Tern, Gelochelidon macrotarsa

Genus Hydroprogne

 * Caspian Tern, Hydroprogne caspia

Genus Thalasseus
(8 species)
 * Lesser Crested Tern Thalasseus bengalensis
 * Royal Tern Thalasseus maximus
 * Great Crested Tern / Greater Crested Tern, Thalasseus bergii
 * Chinese Crested Tern Thalasseus bernsteini
 * Elegant Tern Thalasseus elegans
 * Sandwich Tern Thalasseus sandvicensis
 * Cabot's Tern, Thalasseus acuflavidus
 * West African Crested Tern, Thalasseus albididorsalis

Genus Sternula
(7 species)
 * Fairy Tern, Sternula nereis
 * Damara Tern, Sternula balaenarum
 * Little Tern, Sternula albifrons
 * Saunders's Tern, Sternula saundersi
 * Least Tern, Sternula antillarum
 * Yellow-billed Tern, Sternula superciliaris
 * Peruvian Tern, Sternula lorata

Genus Onychoprion
(4 species)
 * Spectacled Tern, Onychoprion lunatus
 * Bridled Tern, Onychoprion anaethetus
 * Sooty Tern, Onychoprion fuscatus
 * Aleutian Tern, Onychoprion aleuticus

Genus Sterna
(13 species)
 * Roseate Tern, Sterna dougallii
 * White-fronted Tern, Sterna striata
 * Black-naped Tern, Sterna sumatrana
 * Common Tern, Sterna hirundo
 * South American Tern, Sterna hirundinacea
 * Antarctic Tern, Sterna vittata
 * Arctic Tern, Sterna paradisaea
 * Forster's Tern, Sterna forsteri
 * Snowy-crowned Tern, Sterna trudeaui
 * Black-bellied Tern, Sterna acuticauda (possibly Chlidonias)
 * River Tern, Sterna aurantia
 * White-cheeked Tern, Sterna repressa (possibly Chlidonias)
 * Kerguelen Tern, Sterna virgata

Genus Chlidonias
(4 species)
 * Black Tern, Chlidonias niger
 * White-winged Tern or White-winged Black Tern, Chlidonias leucopterus
 * Whiskered Tern, Chlidonias hybridus
 * The Black-fronted Tern, ''Chlidonias albostriatus'

Genus Phaetusa

 * Large-billed Tern, Phaetusa simplex

Genus Larosterna

 * Inca Tern, Larosterna inca

Subfamily Larinae: Gulls

 * Genus Creagrus (Swallow-tailed Gull)
 * Genus Rissa (kittiwakes) (2 species)
 * Genus Pagophila (Ivory Gull)
 * Genus Xema (Sabine's Gull)
 * Genus Chroicocephalus (11 species)
 * Genus Hydrocoloeus (Little Gull)
 * Genus Rhodostethia (Ross's Gull)
 * Genus Leucophaeus (5 species)
 * Genus Ichthyaetus (6 species)
 * Genus Larus (24 species)

Distribution and habitat
The Laridae have spread around the world, and their adaptability has likely been a factor. Most have become much more aerial than their ancestor, which was likely some form of shorebird.