Presbyornis

Presbyornis, live reconstruction

• Green River Formation

Presbyornis is an extinct bird of the order Anseriformes ( Anseriformes ). He was described in 1926 after the discovery of disjointed fossil skeletons of Alexander Wetmore. Presbyornis shows characteristics of different groups of birds, including flamingo -like, long legs and a duck -like beak. Wetmore arranged Presbyornis to the Charadriiformes ( Charadriiformes ) and assumed that from this group emerged the flamingos and the geese birds.

1991 many articulated skeletons of the bird in southwestern Wyoming and southeastern Utah were found in the Green River Formation. The deposition stems from the lower Eocene 50 million years ago. Another large collection of fossils in 1975, inter alia, by Alan Feduccia found 150 kilometers, found in Canyon Creek, near the border between Colorado and Wyoming. Here are the beaks get far better and Presbyornis was recognized as of filtering primitive geese bird.

Features

Skull, skull and beak of Presbyornis were duck -like, curved beak upwards; similar to the recent monkey duck that feeds on algae and zooplankton as Presbyornis.

The frontal bone and the nasal bone were arranged in a V -shape, a feature that can only be found in today's flamingos. This region of the skull of Presbyornis is almost identical to that of a thirty days old Cuba Flamingo chick.

Upper arm bone (humerus ), tibiotarsus and tarsometatarsus were similar to those of the Charadriiformes.

Environment

Presbyornis fossils were always in high concentrations together with broken eggshells found. The birds lived and bred, like flamingos, colonial in large groups on the shores of large lakes. In the same deposits of the Green River Formation were found the remains of palm trees, crocodiles, soft-shelled turtles, and of about 50 species of fish, including stingrays Heliobatis, the herring -like Knightia, various Perciformes, bowfin ( Amia sp.) And moon eyes ( Eohiodon ). The primitive Frigate Limnofregata azygosternon was a possible predator of Presbyornis chicks.

System

Presbyornis is placed in the Presbyornithidae family along with three other species, including Teviornis gobiensis from the Maastrichtian of Nemegt Formation in southern Mongolia, which belongs to the order of Anseriformes ( Anseriformes ).