After Knowlton and her colleagues discovered the differences between the corals through DNA analysis, they examined thin slices of the various corals and found physical distinctions in how the corals construct their walls.
For example, some corals build their walls via a wall-thickening process, whereas other corals build their walls via the insertion of crossbar-like skeletal structures. Once the walls are constructed, however, all the corals look virtually identical.
In future work Knowlton and study co-author Ann Budd of the University of Iowa in Iowa City will re-analyze the morphology of coral colonies to determine what characters to use to classify the marine organisms. These wall-building differences may be the key.
"We need to be able to say this family is characterized by this morphology so we can say which is which," Knowlton said. "But we can't do that now because the whole system is broken."
In addition to forcing scientists to rewrite the long-accepted coral classification system, the finding of a distinct coral family in the Atlantic should force conservationists to rethink their coral preservation strategy, according to the study authors.
Currently the bulk of conservation efforts are focused on species-rich coral reef ecosystems in the Pacific, overlooking most of the Caribbean region of the Atlantic, owing to its lack of unique families and low species diversity.
The finding that at least one third of the Atlantic corals are endemic to the Atlantic means conservationists should not write off the Atlantic just because it has a fewer number of coral species.
"We need to rethink how we identify places for high-priority conservation, because there is a lot more to diversity than species number," Knowlton said.
Côté, whose research has documented the rapid rate of coral decline in the Caribbean, agrees. "Given the fact that Atlantic corals are under tremendous pressures from human activitiesperhaps more so than those in most of the Indo-Pacificthis is a timely and important piece of research," she said.
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