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Concept
Palaeochenoides
Résumé
Palaeochenoides is a genus of the prehistoric pseudotooth birds of somewhat doubtful validity. These were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty.
Only a single species, Palaeochenoides mioceanus, is known to date. The first fossil assigned to it – a distal right femur piece – was found near the source of the Stono River in Charleston County, South Carolina (United States). At first it was believed to be from the Early Miocene Hawthorne Formation – its specific name, seemingly referring to the "Miocene ocean" as presumed habitat but actually a simple spelling error for "miocaenus", "from the Miocene", that was never corrected and hence became valid – alludes to this. But in fact no Hawthorne Formation rocks were known in the Charleston region when the fossil was found, and consequently modern authors consider a Chattian (Late Oligocene) age more likely and suggest the fossil came from the Cooper or Chandler Bridge Formation. Specimen MCZ 2514, a distal left tarsometatarsus fragment from the Ashley River, was more tentatively assigned to P. mioceanus later on; it was also erroneously believed to be from the Hawthorne Formation.
The holotype femur's classification mirrors the recently renewed uncertainties about the pseudotooth birds' placement. At the time of its description, when it was still much surrounded by matrix, it was believed to be from a giant goose or swan. This is referred to in the genus name, which means "ancient goose-like [bird]". But only one year later, the bone had been prepared from the matrix and was submitted to an improvised phenetic analysis of its details. It was compared to that of Anserinae and Dendrocygninae (other Anseriformes were either similar to these or too unlike P. mioceanus), as well as with Pelecanidae, Phaethontidae and Phalacrocoraciformes of the "higher waterbird" radiation, and found to resemble the former in one, the latter in 4 out of 5 traits.
Source officielle
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