The oldest remains referred to this group appeared in the fossil record during the Oligocene in Egypt and Belgium, before palaelodids reached their peak diversity during the Miocene.

However, remains found near Cooper Creek in the Lake Eyre Basin indicate that palaelodids managed to survive in Australia until the Pleistocene.

Palaelodus has previously been thought to be a wader or diver, but recent research indicates that they were better suited for swimming and possibly fed on insect larvae and other aquatic invertebrates.

[1] During the 1940s and 1950s remains similar to the ones from Europe would come to be discovered in the western United States, leading to the establishing of the genus Megapaloelodus by Alden H.

[7] The same year as Mlíkovský's suggested revision, Mayr and Smith described Adelalopus (an anagram of Palaelodus), an entirely new genus of palaelodid from the early Oligocene.

The genera Probalearica as well as the species "Grus" miocenicus and Pliogrus germanicus were all initially described as cranes, but were later found to represent members of the Palaelodidae.

The anatomical features responsible for the later are additionally associated with the presence of webbed feet, lending credence to the hypothesis that they were divers or swimmers.

[8] Among the species of Megapaloelodus, M. peiranoi is thought to be the basalmost member due to its resemblance to some early mirandornithes, specifically Juncitarsus.

[22] † Juncitarsus Podicipediformes † Palaelodidae †Harrisonavis Phoenicopterus Phoenicoparrus Many of the rock units that yielded palaelodid remains are thought to have represented shallow lakes or similar environments at the time the bird fossils were deposited.

Furthermore, many of these are believed to have been either occasionally or permanently brackish or even saline, indicating that these animals had habitat preferences similar to modern flamingos.

[8] In a 1989 study Jacques Cheneval analysed the bird species of the type locality of Saint-Gérand-le-Puy, finding that over half of the identified taxa show a preference for brackish conditions while freshwater exclusives appear to have been absent.

[26] This was later supported by studies that proposed that the locality underwent cyclical dry and wet seasons, with the salinity of the lake changing through the evaporation of water.

These localities mirror those of Europe in preserving not just the remains of juvenile palaelodids but also the fossils of more derived flamingos that seemingly coexisted with their more basal relatives.

The Jebel Qatrani Formation, where two indetermined palaelodids were discovered, is thought to represent a mix of tropical lowland swamp and marshland supported by a series of river channels that empty into the Tethys Ocean.

[28] Palaelodus aotearoa from New Zealand inhabited paleo-Lake Manuherikia, which preserves a rich fauna of water fowl and even the remains of crocodiles.

[7] The Northern Sperrgebiet of Namibia also preserves the presence of freshwater without signs of saline lakes like those inhabited by the European and Australian taxa.

Palaelodids lack several of the adaptations found in flamingos that help them in their filter feeding lifestyle, such as the curved jaw, attachment point for keratinous lamellae and the absence of the pronounced kink in the spine prior to the shoulder girdle.

[4][6] More recently this hypothesis has been called into question, partially due to the fact that no diving bird possesses limbs as elongated as what was present in palaelodids.