''Phoeniconaias siamensis'' is an extinct species of flamingo that lived in northern

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

during the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

period. Its closest living relative is the lesser flamingo.

History and naming

''Phoeniconaias siamensis'' was named in 1991 on the basis of various postcranial material found at the Mae Long Reservoir in Li, northern Thailand. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

, TLi 7, is the distal end of a right

tarsometatarsus The tarsometatarsus is a bone that is only found in the lower leg of birds and some non-avian dinosaurs. It is formed from the fusion of several bones found in other types of animals, and homologous to the mammalian tarsus (ankle bones) and meta ...

, but the referred material also includes elements of both the right and left wings and hindlimbs, a

scapula The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...

and a cervical vertebra. The name derives from Siam, the historical name of Thailand.

Description

One of the main ways to differentiate the three known flamingo genera is through the shape of the beak and the anatomy of the first toe bone, two features not preserved in ''Phoeniconaias siamensis''. However the Li fossils could be referred to the genus ''Phoeniconaias'' based on the anatomy of the trochlea of the

. The trochlea corresponding with the second toe shows an inner face that is elongated and not very round, while that of the third toe creates a sharp point due to it extending far beyond the outer intertrochlear notch. The size also matches the extant lesser flamingo, with ''P. siamensis'' being more robust than its modern relative and only slightly larger. ''Phoeniconaias siamensis'' is diagnosed by the following characteristics. On the supratendinal bridge of the tibiotarsus a large prominence is present. Large cotyla can be seen on the tarsometatarsus and the groove that receives the musculus fibularis is notably furrowed. The humerus bears a deep impression for the brachialis muscle and the ulna possesses a sharp tuberosity. The trochlea of the third toe shows the sharpened point typical for the genus and the distal foramen are located above the intertrochlear notch.

References

{{Taxonbar, from=Q113453740 Phoenicopteridae Fossils of Thailand Fossil taxa described in 1991