Charadriiformes

Charadriiformes is a diverse order of small to medium-large birds. It includes about 350 species and has members in all parts of the world. Most Charadriiformes live near water and eat invertebrates or other small animals; however, some are pelagic (sea birds), some occupy deserts and a few are found in thick forest.

Systematics
The order was formerly divided into these suborders:


 * The Magellanic Plover, sheathbills and thicknees: Chionidi. These birds are found in the Southern Hemisphere.
 * The Egyptian Plover, Pluvialis plovers, slilts and avocets, Ibisbill, oystercatchers, and plovers: Charadrii.
 * The Plains-wanderer, seedsnipes, painted-snipes, jacanas and sandpipers: Limicoli.
 * The buttonquail: Turnici.
 * The Crab plovers, coursers and pratincoles, skuas, auks and gulls, terns and skimmers: Lari.

The Sibley-Ahlquist taxonomy, which has been widely accepted in America, lumps all the Charadriiformes together with other seabirds and birds of prey into a greatly enlarged order Ciconiiformes. However, the resolution of the DNA-DNA hybridization technique used by Sibley & Ahlquist was not sufficient to properly resolve the relationships in this group, and indeed it appears as if the Charadriiformes consititute a single large and very distinctive lineage of modern birds of their own.

The auks, usually considered distinct because of their peculiar morphology, are more likely related to gulls, the "distinctness" being a result of adaptation for diving. Following recent research, a better arrangement may be as follows:

Families in taxonomic order
This is a list of the charadriiform families, presented in taxonomic order.


 * Suborder Chionidi: thick-knees and allies
 * Family Burhinidae: thick-knees
 * Family Chionididae: sheathbills
 * Family Pluvianellidae: Magellanic Plover


 * Suborder Charadrii: plover-like waders
 * Family Pluvianidae: Egyptian plover
 * Family Pluvialidae: Golden plovers
 * Family Recurvirostridae: avocets and stilts
 * Family Ibidorhynchidae: Ibisbill
 * Family Haematopodidae: oystercatchers
 * Family Charadriidae: plovers and lapwings


 * Suborder Limicoli: sandpipers and allies
 * Family Pedionomidae: Plains Wanderer
 * Family Thinocoridae: seedsnipe
 * Family Rostratulidae: painted snipe
 * Family Jacanidae: jacanas
 * Family Scolopacidae: snipe, sandpipers, phalaropes, and allies


 * Suborder Turnici: buttonquails
 * Family Turnicidae: buttonquails


 * Suborder Lari: gulls and allies
 * Family Dromadidae: Crab Plover
 * Family Glareolidae: pratincoles and coursers
 * Family Stercorariidae: skuas
 * Family Alcidae: puffins, guillemots, murres, and allies
 * Family Laridae: gulls
 * Family Rhynchopidae: skimmers
 * Family Sternidae: terns

List is from:

More conservatively, the Thinocori could be included in the Scolopaci, and the Chionidi in the Charadrii, or the Glareolidae could be placed in a suborder of their own. The buttonquails are of indeterminate, quite basal position in the Lari-Scolopaci sensu lato group. The arrangement as presented here is a consensus of the recent studies.

Evolution
That the Charadriiformes are an ancient group is also borne out by the fossil record. Much of the Neornithes' fossil record around the Cretaceous–Tertiary extinction event is made up of bits and pieces of birds which resemble this order. In many, this is probably due to convergent evolution brought about by semi-aquatic habits. Specimen VI 9901 (López de Bertodano Formation, Late Cretaceous of Vega Island, Antarctica) is probably a basal charadriiform somewhat reminiscent of a thick-knee. However, more complete remains of undisputed charadriiforms are known only from the mid-Paleogene onwards. Present-day orders emerged around the Eocene-Oligocene boundary, roughly 35-30 mya. Basal or unresolved charadriiforms are:
 * "Morsoravis" (Late Paleocene/Early Eocene of Jutland, Denmark) - a nomen nudum?
 * Jiliniornis (Huadian Middle Eocene of Huadian, China) - charadriid?
 * Boutersemia (Early Oligocene of Boutersem, Belgium) - glareolid?
 * Turnipax (Early Oligocene) - turnicid?
 * Elorius (Early Miocene Saint-Gérand-le-Puy, France)
 * "Larus" desnoyersii (Early Miocene of SE France) - larid? stercorarid?
 * "Larus" pristinus (John Day Early Miocene of Willow Creek, USA) - larid?
 * Charadriiformes gen. et sp. indet. (Bathans Early/Middle Miocene of Otago, New Zealand) - charadriid? scolopacid?
 * Charadriiformes gen. et sp. indet. (Bathans Early/Middle Miocene of Otago, New Zealand) - charadriid? scolopacid?
 * Charadriiformes gen. et sp. indet. (Bathans Early/Middle Miocene of Otago, New Zealand) - larid?
 * Charadriiformes gen. et sp. indet. (Sajóvölgyi Middle Miocene of Mátraszõlõs, Hungary
 * "Totanus" teruelensis (Late Miocene of Los Mansuetos, Spain) - scolopacid? larid?

The "transitional shorebirds" ("Graculavidae") are a generally Mesozoic form taxon formerly believed to constitute the common ancestors of charadriiforms, waterfowl and flamingos. They are now assumed to be mostly basal taxa of the charadriiforms and/or "higher waterbirds", which probably were two distinct lineages 65 mya already, and few if any are still believed to be related to the well-distinct weaterfowl. Taxa formerly considered graculavids are:
 * Laornithidae - charadriiform? gruiform?
 * Laornis (Late Cretaceous?)
 * "Graculavidae"
 * Graculavus (Lance Creek Late Cretaceous - Hornerstown Late Cretaceous/Early Palaeocene) - charadriiform?
 * Palaeotringa (Hornerstown Late Cretaceous?) - charadriiform?
 * Telmatornis (Navesink Late Cretaceous?) - charadriiform? gruiform?
 * Scaniornis - phoenicopteriform?
 * Zhylgaia - presbyornithid?
 * Dakotornis
 * "Graculavidae" gen. et sp. indet. (Gloucester County, USA)

Other wader- or gull-like birds incertae sedis, which may or may not be Charadriiformes, are:
 * Ceramornis (Lance Creek Late Cretaceous)
 * "Cimolopteryx" (Lance Creek Late Cretaceous)
 * Palintropus (Lance Creek Late Cretaceous)
 * Torotix (Late Cretaceous)
 * Volgavis (Early Paleocene of Volgograd, Russia)
 * Eupterornis (Paleocene of France)
 * Neornithes incerta sedis (Late Paleocene/Early Eocene of Ouled Abdoun Basin, Morocco)
 * Fluviatitavis (Early Eocene of Silveirinha, Portugal)