Will the Tasman booby survive being discovered for the third time? That's the hope of researchers at New Zealand's University of Canterbury, who have recently proved that this tasty bird is not as extinct as was believed.
The Tasman booby (Sula tasmani), a subspecies of the masked booby (Sula dactylatra), was nearly eaten into extinction at two points in history. Polynesian settlers to Australia and New Zealand first discovered the birds in the 13th century, and quickly hunted them until only a small population remained on Lord Howe Island (a small, self-governed Pacific island east of Australia). The booby lasted there another 500 years, until Western sailors came by and restarted the feast. By the end of the 18th century, it appeared that the very last Tasman booby had been consumed, and the species has been assumed extinct for decades.
That assumption has now changed. In research published Aug. 12 in the online edition of the journal Biology Letters, scientists prove that the Tasman booby is not extinct, but has been hiding in plain sight all along on Lord Howe Island, misclassified as plain old masked boobies. "What was once considered to be an extinct species, the Tasman booby (Sula tasmani), turns out be a subspecies of a living species, the masked booby (Sula dactylatra fullagari). And now these charismatic seabirds have a new name—Sula dactylatra tasmani," said lead author Tammy Steeves in a prepared statement.
The scientists accomplished this rediscovery not in the field but in the lab, analyzing classic paleontological data as well as ancient and modern DNA data.
First, the team compared standard morphometric measurements of fossil material collected from Norfolk Island (the first place the birds were eaten up, located east of Lord Howe Island) to modern specimens collected in the northern Tasman Sea and previously presumed to be masked boobies. The team then used modern DNA lab methods to compare mitochondrial control region sequences from Norfolk Island fossils with those from a wider sample of modern bird throughout the boobies' range. Both approaches confirmed the birds on Lord Howe Island as Tasman boobies.
There are differences in appearance, despite the morphometric and genetic matchup. The modern boobies living on Lord Howe Island have longer wings and sepia-colored eyes, not the short wings and yellow eyes of historical samples. Stevens and her team plan further research to find out why these changes have emerged over the last few centuries.
Image: (S. d. personata), a subspecies related to the now–not extinct Tasman booby (via Wikipedia)