Seabird in the Cretaceous, with a species called "Tytthostonyx glauconiticus", which seems allied to the Procellariiformes and Pelecaniformes. In the Paleogene both pterosaurs and marine reptiles became extinct, allowing seabirds to expand ecologically. These post-extinction seas were dominated by early Procellariidae, giant penguins and two extinct families, the Pelagornithidae and the Plotopteridae (a group of large seabirds that looked like the penguins). Modern genera began their wide radiation in the Miocene, although the genus "Puffinus" (which includes today's Manx shearwater and sooty shearwater) might date back to the Oligocene. The highest diversity of seabirds apparently existed during the Late Miocene and
Tropical shearwater Tropical shearwater The tropical shearwater ("Puffinus bailloni") is a seabird in the family Procellariidae formerly considered conspecific with Audubon's shearwater ("Puffinus lherminieri"). There are five listed subspecies of the tropical shearwater: The tropical shearwater is found in the tropical parts of the western Indian Ocean from east Africa to southern India and in similar regions of the Pacific from just to the southeast of Japan to French Polynesia. The total population has not been definitively quantified. Subspecies "P. b. dichrous" is estimated to number 1,000–10,000 pairs on the Line Islands and 10,000–100,000 pairs on the Phoenix Islands, with the nominate