#phoenicopteriformes

American Flamingo (Phoenicopterus ruber), family Phoenicopteridae, order Phoenicopteriformes, northern Colombia

A greater flamingo (Phoenicopterus roseus) takes flight in Camargue, France

Dinosaur Palaelodus ambiguus, of Late Paleogene, France and Germany!

The Oligocene is often considered an important time of transition, a link between the “archaic” world of the tropical Eocene and the more “modern” ecosystems of the Miocene. During this time one group of dinosaurs, the bizarre Eocene Phoenicopteriformes, which today are represented only by the living family Phoenicopteridae (flamingoes), slowly began to diversify. The genus Palaelodus, a long-necked semi-aquatic phoenicopteriforme, was highly successful, living worldwide, and surviving from the Oligocene to the Miocene, with records indicating at least one species (or at least a relative) survived into the Pleistocene of Australia. Palaelodus’ skull shares ancestral traits with both flamingos and grebes (the closest living relative of flamingos). Their bills are straight and lack the internal spongy texture of flamingos, but their skull clearly shows the presence of salt glands, a trait shared with flamingoes. Although still relatively long, Palaelodus’ legs were not nearly as elongated as those of modern flamingos. It did not seem to have developed the mechanisms yet for filter feeding, and was likely more adept at swimming and using its long neck for foraging for small invertebrates like caddisflies and snails. The species we are looking at here is Palaelodus ambiguus, from the Late Oligocene to Middle Miocene of France and Germany. Known from thousands of bones, P. ambiguus is one of the best known species of Palaelodus.

Social behavior for Palaelodus seems to have varied between species. Species from Australia and New Zealand may have been less social, as their fossils are less commonly found, while species from Europe, like Palaelodus ambiguus, likely lived in large flocks due to their bones being found in great numbers. Similar to flamingos, they inhabited saline and brackish lakes. Fossils of Palaelodus ambiguus have been found in the Saint-Gérand-le-Puy area in France and the Mainz Basin in Germany. Material from the Oligocene to Miocene Taubuté Basin (Tremembé Formation) of São Paulo, Brazil, has also been tentatively assigned to this species.

(Sources - 1, 2, 3, 4)

Our next order of birds are the Phoenicopteriformes, commonly called “flamingos”. They are comprised of one family, Phoenicopteridae, and 3 genera.

Flamingos are most well-known for having varying degrees of pink coloration derived from their diet. Young flamingos hatch with grayish plumage, but adults range from light pink to bright red due to aqueous bacteria and beta-carotene obtained from their diet of blue-green algae (phylum Cyanobacteriota), diatoms, and/or small invertebrates such as Brine Shrimp (genus Artemia). Some species, such as the American Flamingo (Phoenicopterus ruber) (image 1) tend to be more reddish-pink due to a greater availability of beta-carotene, while other species are a more pale pink due to ingesting a smaller amount of the pigment. Due to their filter-feeding diet, flamingos have unique bills which are specially adapted to separate mud and silt from the food they eat, and are used upside-down. Hairy structures called lamellae line the bill and tongue, filtering out food particles. Flamingos have long necks and legs. Their feet are webbed to aid with swimming and to stomp their feet in the mud to stir up food from the bottom. They live in tropical areas in the Americas, Africa, and Eurasia, typically in saltwater lagoons or high saline freshwater environments. Though flamingos prefer to drink freshwater, they are equipped with glands under their eyes that remove extra salt from their bodies. This organ allows them to drink saltwater as well, and many flamingo species are extremists: animals which live in extreme environments that many other organisms can not survive in.

Vocalizations play an important role in parent-chick recognition, ritualized displays, and keeping large flocks together, and flamingos are quite noisy. They are very social birds, and live in colonies whose population can number in the thousands. Before breeding, flamingo colonies split into breeding groups of about 15 to 50 birds. Both males and females in these groups perform synchronized ritual displays, which involve stretching their necks upwards, head-flagging, and flapping their wings (see gif below). The displays do not seem directed towards an individual, but occur randomly, and help pair up those birds that do not already have mates. Flamingos form strong pair bonds, though in larger flocks they may change mates due to having more options. A pair will establish and aggressively defend a nesting site, usually from other flamingo pairs trying to commandeer it. The nest is typically made of mud, into which the female will lay one large, chalky-white egg. Both the male and the female contribute to building the nest, and to protecting the nest and egg. For the first six days after the chick hatches, the parents and chick stay in the nesting sites. Both the male and the female feed their chick with a kind of crop milk, produced in glands lining the upper digestive tract. Crop milk contains both fat and protein, as with mammalian milk, but unlike mammalian milk, it contains no carbohydrates. At around 7–12 days old, flamingo chicks begin to move out of their nests and explore their surroundings. When they are 2 weeks old, the chicks congregate in groups, called "microcrèches", and their parents leave them alone. After a while, the microcrèches merge into "crèches" containing thousands of chicks, which are marshaled by a few adults. When young flamingos are around 3 to 3.5 months old, their flight feathers will finish growing in, allowing them to fly and join the main flock.

Phoenicopteriformes evolved in the Eocene, with modern flamingos, such as Elornis, appearing in the Oligocene, around 25 million years ago. They form a clade, Mirandornithes, with the grebes (order Podicipediformes), and the ancestor of both orders was likely highly aquatic.

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Greater Flamingo (Phoenicopterus roseus)