Pelecaniformes

Northern Gannet ( Morus bassanus )

The Pelecaniformes ( Pelecaniformes ) are an order of birds, which include, inter alia, cormorants, pelicans and boobies. Named these water birds are after Ruderfuß in which all the toes are webbed; apart from that there are few common features, and the order is no longer valid today as monophyletic.

Features

At first glance, Pelecaniformes seem not to have much in common. They are named after the construction of the feet, in which all four toes are connected by webbing, including the hind -directed forward and inward. Another common characteristics of all families is the absence of a brood patch. All Pelecaniformes have featherless skin of the throat, forming a more or less large throat pouch. Nostrils are closed or extremely stunted.

All species of this order catch their food, which consists mainly of fish, underwater. While snake -necked birds and cormorants only the springs are water repellent below the deck plumage, this is the case with other members of the order for the entire plumage.

Reproduction

It is typical of the species of this order, that they found large nesting colonies. They often are located on remote islands and cliffs. Most species build compact nests, which are built by both partners. The young are helpless at hatching and are fed by the parents birds with hochgewürgtem feed.

Phylogeny

Because even with the recent families the unique assignment to the Ruderfüßern is often unclear (see Chapter systematics), this is even more true for the fossil representatives. From the earliest representatives only very fragmentary traces are preserved, so that even their rough classification is controversial. Thus, the genus has been Elopteryx the Cretaceous initially described as a Coelurosaurier, while others identified as a bird, sometimes even as early representatives of the boobies.

The most important fossil families of the Pelecaniformes are the Pelagornithidae and Plotopteridae.

Pelagornithidae

The Pelagornithidae were large seabirds that (possibly Paleocene ) were common to the Miocene worldwide from the Eocene. They had wingspans up to six meters ( Osteodontornis ) and recalled in habit of albatrosses. Their similarities with the Procellariiformes go so far that some paleontologists see them as possible evidence of a common origin of Procellariiformes and Ruderfüßern. The by an extensive, but mostly fragmentary fossil record best-known representative is Osteodontornis who lived on the northern hemisphere from the early Oligocene to Pliocene, and one of the largest birds of its time.

Plotopteridae

While the actual membership of the Pelagornithidae remains questionable to Ruderfüßern were the Plotopteridae almost certainly relatives of the modern cormorants and darters. In convergent evolution they had developed similarities with penguins, with whom they were not related. These flightless birds living from Eocene to Miocene to the coasts of the North Pacific.

Recent families

From the Eocene pelicans, frigate birds and tropic birds are already in use (although some paleontologists deny the affiliation of the fossil record on these families); Oligocene cormorants and darters appear boobies, in the Miocene.

System

For the first time Pelecaniformes 1867 by Thomas Henry Huxley were prepared as kinship circle. He called the order Dysporomorphae - later the name Steganopodes was widespread. Traditionally, the Tropicbird ( Phaethontidae ), the frigate ( Fregatidae ), the Pelicans ( Pelecanidae ), the boobies ( Sulidae ), cormorants ( Phalacrocoracidae ) and darters ( Anhingidae ) were attributed to order. For a long time, but the affiliation of the tropic birds has been questioned. So Chandler said that in truth they are strongly divergent relatives of the gulls were - a view that has been taken yet in 1978 by Howell, who pointed out anatomical similarities of Tropikvögeln and terns. The frigate, however, were viewed since 1888 repeatedly as relatives of the Procellariiformes. Recent analyzes confirm that the Tropicbird are related neither with the other families still another bird order. Therefore, they are placed in an order of its own recently, the Phaethontiformes.

The closest relatives of pelicans are against the Shoebill ( Balaeniceps rex ) and the hammerhead ( Scopus umbretta ), two birds that are native to tropical Africa and in the traditional system to the walking birds ( Ciconiiformes ) are expected. Sister group of the clade formed by all three taxa are the herons ( Ardeidae ) and ibises and spoonbills ( Threskiornithidae ). Sister group of the clade formed by all five taxa are the leftover Rüderfüßer. To get back to monophyletic taxa assigns the International Ornithological Committee all the families of the Ciconiiformes to the storks ( ciconiidae ) the Pelicaniformes to. In contrast, the American Ornithologists ' Union represents the Shoebill and the hammer head in the previously mono- generic family Pelecanidae and these, as well as herons, ibises and spoonbills in the order Pelicaniformes that fact with the exception of pelicans, undergoes a completely different composition. The remaining Pelecaniformes be made the new order Suliformes ..

The probable kinship relations with the new names of the AOU are following cladogram again. The traditionally Ruderfüßern the associated taxa are highlighted in bold:

Storks ( ciconiidae )

Frigate ( Fregatidae )

Boobies ( Sulidae )

Darters ( Anhingidae )

Cormorants ( Phalacrocoracidae )

Herons ( Ardeidae )

Ibises and Spoonbills ( Threskiornithidae )

Hammerhead ( Scopus )

Pelicans ( Pelecanus )

Shoebill ( Balaeniceps )