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
Audubon's shearwater homogeneous north-western Indian Ocean range, but not in the ecologically more diverse and by far larger Pacific range of "dichrous". These unresolved problems notwithstanding, this clade – possibly including the preceding one – has been proposed to constitute a separate species, the tropical shearwater or Baillon's shearwater, "Puffinus bailloni". These taxa could not be included in the most recent studies due to lack of material. The case of "gunax" seems fairly straightforward – as certainly as this can possibly be said in the absence of new data, it belongs to the "bailloni" clade either as a distinct subspecies, or, more