Onychoprion is a genus of four species of in the family Laridae. The genus name is from Ancient Greek , "claw" or "nail", and , "saw".[ or "brown-backed terns",]
Species
Although the genus Onychoprion was first described in 1832 by Johann Georg Wagler, the species in the genus were generally retained within the larger genus Sterna, the genus that holds most terns, until a study in 2005 showed that this treatment was paraphyly, with these four species less closely related to typical Sterna terns, than several other terns long treated in other genera like Chlidonias and Larosterna.[Bridge, E. S.; Jones, A. W. & Baker, A. J. (2005). A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution . Molecular Phylogenetics and Evolution 35: 459–469.]
Onychoprion diverged early from other terns about 16–18 million years ago, with only the very different noddies ( Anous and Gygis) diverging earlier.
Three of the four species are Tropics, and one has a sub-polar breeding range. The sooty tern has a pan-tropical distribution; the bridled tern also breeds across the Tropical Atlantic and Indian Ocean but in the central Pacific it is replaced by the spectacled tern. The Aleutian tern breeds around Alaska and Siberia but winters in the tropics around South East Asia.
Cultural aspects
Manutara is the Rapa Nui language name for spectacled and sooty terns. Both arrive at Easter Island and hatch their eggs on the island called Motu Nui, an event that was used for an annual rite called Tangata manu.
