Storm-petrels - Taxonomy

Taxonomy

Two subfamilies are traditionally recognized. The Oceanitinae are mostly found in southern waters (though the Wilson's Storm Petrel regularly migrates into the northern hemisphere); there are 7 species in 5 genera. The Hydrobatinae are the two genera Hydrobates and Oceanodroma. They are largely restricted to the northern hemisphere, although a few can visit or breed a short distance beyond the equator.

Cytochrome b DNA sequence analysis suggests that the family is paraphyletic and may be more accurately treated as distinct families. The same study found that the storm petrels are basal within Procellariiformes. The first split was the subfamily Oceanitinae, with the Hydrobatinae splitting from the rest of the order at a later date. Few fossil species have been found, with the earliest being from the Upper Miocene.