Scientists discover new pacific iguana.
Pacific iguanas almost have 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 varieties face threats from loss and alteration of their habitat, as well as from feral cats, mongooses, and goats that eat iguanas or their food sources.
"Our new understanding of the species diversity in this group is a first step in identifying conservation targets," explains Robert Fisher, research zoologist at the U.S. Geological Survey in San Diego, Calif., and coauthor of the study on the new iguana.
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 now is listed as critically endangered on the "Red List" of the International Union for Conservation of Nature, headquartered in Washington, D.C.
"This new study indicates that the other previously-identified iguana species, Brachylophus fasciatus, is probably critically endangered as well," Fisher reports.
The mystery of how the Pacific iguanas originally arrived long has puzzled biologists and geographers. Their closest relatives are found nearly 5,000 miles away across the ocean in the New World. The highest islands of Fiji have been above sea level continuously for at least 16,000,000 years, and the study's findings suggest that the Pacific iguanas (extinct and living) likely were on the islands much of that time. Ancestors of the Pacific iguanas may have arrived up to 13,000,000 years ago after making a 5,000-mile rafting trip from the Americas.
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 tends to reduce biodiversity," explains Fisher.
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|Title Annotation:||Ecological Diversity|
|Publication:||USA Today (Magazine)|
|Date:||Jun 1, 2009|
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