Tropicbirds

Taxonomy, systematics and evolution

Tropicbirds were traditionally grouped in the orderPelecaniformes, which contained the pelicans, cormorants and shags, darters, gannets and boobies and frigatebirds. In some classifications tropicbirds and frigatebirds were sometimes placed as sister taxa. Still, their own set of peculiarities gave them their suborder. In the Sibley–Ahlquist taxonomy, the Pelecaniformes were united with other groups into a large "Ciconiiformes". More recently, this grouping is massively paraphyletic (missing closer relatives of its distantly related groups) and split again.