Xenorhynchopsis
| Xenorhynchopsis Temporal range:
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|---|---|
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| Restoration of X. tibialis. | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Phoenicopteriformes |
| Family: | Phoenicopteridae |
| Genus: | †Xenorhynchopsis De Vis, 1905 |
| Species | |
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Xenorhynchopsis is an extinct genus of flamingo from the Pliocene to Pleistocene Lake Eyre basin of Australia. Initially described as species of stork, the two known Xenorhynchopsis species are vastly different in size. X. minor is the older and small of the two species, ranging from the Pliocene to Pleistocene and being described as having reached a size smaller than that of the lesser flamingo. X. tibialis meanwhile appears to have been restricted to Pleistocene strata and was notably bigger, being counted as one of the biggest known flamingos in the fossil record.
History
The fossils of Xenorhynchopsis were initially described by
Description
The traits that distinguish Xenorhynchopsis from other flamingo genera are deemed questionable by Rich and colleagues. The distal end of the tibiotarsus is described as deeper than it is wide with a shaft that flares less towards the distal end when compared to extant species. Towards the distal end the tendinal canal has larger openings, another trait shared by both species and setting them apart from modern flamingos. Additionally, the internal condyle lacks a notch in both species.[1]
The fossil material of X. tibialis resembles the black-necked stork in size and is larger than that of extant flamingos. Rich and colleagues write that only Phoeniconotius exceeds Xenorhynchopsis tibialis in size. X. minor meanwhile is somewhat smaller, if stouter, than the lesser flamingo and approximately in the same size range as Phoenicopterus stocki and Phoenicopterus minutus.[1]
Paleobiology
During the Pliocene at least three flamingo species existed at Lake Kanunka, Xenorhynchopsis minor, Phoeniconaias proeses and what may be the modern greater flamingo. Xenorhynchopsis tibialis appears to have been limited to the Pleistocene and possibly died out when the inland lakes these birds depended on dried up, leading to the local extinction of flamingos in Australia. All four species could be found in the sediments of Lower Cooper Creek, however due to them appearing in different localities, many of which lack precise information regarding their age, it is uncertain if they actually occurred alongside one another.[1] According to Camens and Worthy, footprints found in the Tirari Formation may have been left by Xenorhynchopsis minor, as they appear to be too large to be attributed to P. proeses and too small to have belonged to X. tibialis. The greater flamingo is however another possible candidate.[3]