Phaethontidae
| Tropicbirds Temporal range: Early Eocene to present |
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|---|---|
_with_chick.jpg) |
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| Red-billed tropicbird (Phaethon aethereus mesonauta) with chick, Little Tobago | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Clade: | Eurypygimorphae |
| Order: |
Phaethontiformes Sharpe, 1891 |
| Family: |
Phaethontidae Brandt, 1840 |
| Genus: |
Phaethon Linnaeus, 1758 |
| Species | |
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3, see text |
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3, see text
Tropicbirds are a family, Phaethontidae, of tropical pelagic seabirds now classified in their own order Phaethontiformes. Their relationship to other living birds is unclear, and they appear to have no close relatives. There are three species in one genus, Phaethon. The scientific names are derived from Ancient Greek phaethon, "sun". They have predominantly white plumage with elongated tail feathers and small feeble legs and feet.
Tropicbirds were traditionally grouped in the order Pelecaniformes, which contained the pelicans, cormorants and shags, darters, gannets and boobies and frigatebirds; in the Sibley-Ahlquist taxonomy, the Pelecaniformes were united with other groups into a large "Ciconiiformes". More recently this grouping has been found to be massively paraphyletic (missing closer relatives of its distantly related groups) and split again.
Microscopic analysis of eggshell structure by Konstantin Mikhailov in 1995 found that the eggshells of tropicbirds lacked the covering of thick microglobular material of other Pelecaniformes.
Recent research suggests that the Pelecaniformes as traditionally defined are paraphyletic too. The tropicbirds and the related prehistoric family Prophaethontidae are considered a distinct order, Phaethontiformes, not closely related to any other living birds. Some early studies in the last decade suggested a distant relationship to Procellariiformes, but since 2004 they have been placed in Metaves, or in a lineage with no affinities with Procellariiformes, by the results of most recent molecular studies.
Jarvis, et al.'s 2014 paper "Whole-genome analyses resolve early branches in the tree of life of modern birds" aligns the tropicbirds most closely with the sunbittern and the kagu of the Eurypygiformes, with these two clades forming the sister group of the "core water birds", the Aequornithes, and the Metaves hypothesis abandoned.
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Wikipedia