"Our study represents important progress towards understanding the evolution and biodiversity of corals and provides a foundation for future work. Since coral ecosystems are increasingly threatened, there is a need to characterize and understand coral species in terms of interbreeding groups as opposed to nominal morphological units", said Zac Forsman, who led a team of researchers from the Hawai'i Institute of Marine Biology carrying out the molecular studies.

Difficult to tell apart

Skeletal shape is currently used to differentiate coral species. According to the authors, this can make them notoriously difficult to tell apart as shape can change independent of reproductive isolation or evolutionary divergence, the factors most commonly understood to define 'species.'

Genetic analysis

By studying the genetic characteristics of coral at specific DNA locations, Forsman and his colleagues were able to confirm some species groupings, while finding evidence that others may not be as clearly defined as has been thought.

The authors said, "Here, we demonstrate that integration of taxonomy with analysis of multiple molecular markers reveals cryptic patterns of species diversity within the coral genus Porites.

Our approach shows that morphological characters previously thought capable of delineating species must be re-examined to accurately understand patterns of evolution, endemism, and biodiversity in reef-building coral."

The authors' research will be very useful to the current ecological efforts to preserve coral. According to Forsman, "Currently used species definitions are likely to be misleading and confound attempts to identify, understand, and conserve coral biodiversity or to recognize its loss."

...morphological characters previously thought capable of delineating species must be re-examined...