Puffinus be divided in what has been called the "Puffinus" and the "Neonectris" group after notable species; the latter has been separated as a distinct genus named "Ardenna". The former is taxonomically confusing, with species having been split and remerged in the last years. The genus "Puffinus" contains the following species: Several fossil species which became extinct long ago are also known. The proportion of larger ("Neonectris") species apparently was larger before the Pliocene, i.e. before marine mammals diversified: ""Puffinus" arvernensis" (Early Miocene of France) is now considered a primitive albatross of the fossil genus "Plotornis". Puffinus Puffinus is a genus
Christmas shearwater and introduced black rats took eggs and chicks. In 1985, the population on Sala-y-Gómez, a nature sanctuary, was estimated at 5,000. With its wide range and considerable numbers, the Christmas shearwater is considered a species of least concern by the IUCN. Christmas shearwater The Christmas shearwater ("Puffinus nativitatis") is a medium-sized shearwater of the tropical Central Pacific. It is a poorly known species due to its remote nesting habits, and it has not been extensively studied at sea either. It is one member of a very ancient lineage of the small "Puffinus" species. Its only close living relative is the