Ancestors of living creatures that exist today can sometimes have traits to surprise people. A similar discovery was made in a new study by scientists.
In the study published in the journal Zootaxa, Zoologists David Steadman of the Florida Museum of Natural History and Oona M. Takano of the University of New Mexico have described a new extinct species of pigeon that lived in the Pacific islands. The fossils of this pigeon species have been found on six islands (Foa, Lifuka, ‘Uiha, Ha’afeva, Tongatapu, and ‘Eua) in the Kingdom of Tonga.
According to the scientists, fossils show that the newly described genus and species, called Tongoenas burleyi, inhabited the Tongan islands for at least 60,000 years, but vanished within a century or two of human arrival around 2,850 years ago. The ancestor of today’s modern pigeons was about 20 inches (50.8 cm) long, not including the tail, and weighed at least five times as much as the average city pigeon. But despite such a large size, Tongoenas burleyi was able to fly.
This canopy-dwelling species lived on fruit-bearing trees and fed on fruits like mango, guava, and chinaberry. The scientists also believe that the pigeon also acted as an essential forest cultivator by spreading seeds to new locations. About the size of a large duck, T. burleyi was likely capable of swallowing fruit as big as a tennis ball.
“Some of these trees have big, fleshy fruit, clearly adapted for a big pigeon to gulp whole and pass the seeds,” said study lead author David Steadman. “Of the fruit-eating pigeons, this bird is the largest and could have gulped bigger canopy fruit than any others. It takes co-evolution to the extreme.”
“The absence of T. burleyi from the Tongan islands could threaten the long-term survival of local trees that depended on the pigeon as a seed transporter,” added study co-author Oona Takano, a doctoral student at the University of New Mexico. “The pigeon species on Tonga today are too small to eat large fruits, which imperils certain fruit trees.”
As they began excavating charred and broken remains of T. burleyi at archaeological sites, they realized that it was another human-caused extinction. “Pigeons and doves just plain taste good,” Steadman said.
The study author also notes that before the arrival of humans, the islands of Tonga were inhabited by at least nine species of pigeons from six genera, of which only four species in three genera exist today.
“Given that there are 350 species of pigeons and doves, people might suspect these big changes in lifestyle evolved independently many times,” Steadman said. “But right now, we don’t have evidence that it happened more than once – at least in the tropical Pacific.”
Steadman hypothesized the species featured the bright, even gaudy, the plumage of other pigeons that live in treetops, where intense colors provide better camouflage than the muted browns and grays of pigeons that live on the ground.
- A new genus and species of pigeon (Aves, Columbidae) from the Kingdom of Tonga, with an evaluation of hindlimb osteology of columbids from Oceania. DOI: 10.11646/zootaxa.4810.3.1