Manx shearwater Morten Thrane Brünnich as "Procellaria puffinus" in 1764. The current scientific name "Puffinus" derives from "puffin" and its variants, such as poffin, pophyn and puffing, which referred to the cured carcass of the fat nestling of the shearwater, a former delicacy. The original usage dates from at least 1337, but from as early as 1678 the term gradually came to be used for another seabird, the Atlantic puffin. The current English name was first recorded in 1835 and refers to the former nesting of this species on the Isle of Man. The Manx shearwater is with a wingspan and weighs
Procellariidae with "Pseudobulweria" being phylogenetically closer to the "Puffinus" shearwaters than the "Pterodroma" gadfly petrels, and "Aphrodroma" (the Kerguelen petrel) possibly being closely related to the shearwaters or the fulmars. The prions, according to Nunn and Stanley, were among the larger shearwater group. The "Calonectris" shearwaters were placed close to the two "Puffinus" clades (closer to the Puffinus, or small, clade) and both were distant to the "Procellaria" shearwaters. The relationships between the genera and within the genera are still the subject of debate, with researchers lumping and splitting the species and genera within the family and arguing about the position