new iguana has been discovered in the central regions of Fiji.
The colorful new species, named Brachylophus
bulabula, joins only two other living Pacific iguana species,
one of which is critically endangered. The scientific name bulabula is
a doubling of bula, the
Fijian word for ‘hello,’ offering an even more
Pacific iguanas have almost disappeared as the result of human
presence. Two species were eaten to extinction after people arrived
nearly 3,000 years ago. The three living Brachylophus iguana species face
threats from loss and alteration of their habitat, as well as from
feral cats, mongooses and goats that eat iguanas or their food source.
“Our new understanding of the species diversity in this group is a
first step in identifying conservation targets,” said Robert Fisher, a
research zoologist at the U.S. Geological Survey in San Diego, and
coauthor of a study on the new iguana with scientists from the
Australian National University and Macquarie University in Australia.
An important study finding for conservation of the genetic diversity in
these iguanas is that, with only one exception, each of the 13 islands
where living iguanas were sampled showed at least one distinct iguana
genetic line that was not seen elsewhere.
The Fiji crested iguana, Brachylophus
vitiensis, is gone from many islands it once occupied and is now
listed as Critically Endangered on the “Red List” of the International
Union for Conservation of Nature. The IUCN is the largest global
environmental network. “Unfortunately, this new study indicates that
the other previously-identified Pacific iguana species, Brachyophus fasciatus, is probably
critically endangered also,” Fisher said.
The mystery of how the Pacific iguanas originally arrived has long
puzzled biologists and geographers. Their closest relatives are found
nearly 5,000 miles away across the ocean in the New World.
“The distinctive Fijian iguanas are famous for their beauty and also
their unusual occurrence in the middle of the Pacific Ocean because all
of their closest relatives are in the Americas,” said Scott Keogh, an
Associate Professor at the Australian National University in Canberra,
Australia, and lead author of the study.
The highest islands of Fiji have been continuously above sea level for
at least the last 16 million years, and the current study’s findings
suggest that the Pacific iguanas, both extinct and living, were likely
on the islands much of that time. Ancestors of the Pacific iguanas may
have arrived up to 13 million years ago after making a 5,000 mile
rafting trip from the New World.
Realizing that scientists are just now describing the diversity in even
such colorful and distinctive groups as Pacific iguanas is important in
setting biodiversity targets for the Pacific Basin.
"This island basin is currently under attack by a number of invasive
species such as the brown tree snake, various rat species and the coqui
frog, which tend to reduce biodiversity," said Fisher. "Climate change
may reduce coastal habitats and alter coastlines in the Pacific,
further putting biodiversity at risk. A more accurate understanding of
the patterns and processes that impact diversity in these unique island
groups will help land managers set appropriate goals for conservation
of these resources."
The new discovery is published in a recent special edition of Philosophical Transactions of the Royal
Society B that pays tribute to Charles Darwin’s contribution to
the Pacific region. The other coauthors of the study are Danielle
Edwards at the Australian National University, and Peter Harlow at
Macquarie University in Australia.