Researchers at the University of Hawaiʻi report that zoantharians, a colorful family of anemone-like corals, are challenging traditional ideas about ocean evolution. Found on reefs across both the Atlantic and Indo-Pacific, these corals look nearly identical despite vast distances, and a new global study shows only weak genetic and physical differences among them. This surprising similarity could prompt scientists to reconsider how reef species disperse and maintain resilience worldwide.
Global Atlas Uncovers a Surprise
As reported in Frontiers of Biogeography, the peer-reviewed paper pulled together the first global “atlas” for zoantharians by blending DNA data with museum and field records from Mexico to the Philippines. The authors report that, unlike most reef animals, zoantharians show strikingly weak differentiation between the Atlantic and Indo-Pacific. The study was led by Maria “Duda” Santos of UH Mānoa’s Hawaiʻi Institute of Marine Biology.
Long-Lived Larvae and Ocean Rafts
Coverage of the paper notes that researchers think the animals’ secret is pure mobility. Young zoantharian larvae appear able to hang on in open water for more than 100 days, and adults can hitch rides on floating debris to cross vast ocean basins. That long pelagic window, combined with an unusually slow evolutionary rate, helps explain why far-flung populations still look and behave like close relatives, Phys.org reports.
What This Means For Reefs
That capacity to spread matters because zoantharians can slip into spaces left behind by stressed stony corals and in some places take over large patches of reef surface. “In some habitats impacted by stress, some zoantharian species can outcompete stony corals,” Maria “Duda” Santos said, as detailed by the University of Hawaiʻi News.
A Global Team, A Local Lab
The paper reflects an international effort, with researchers from Hawaiʻi, Okinawa, Russia, Brazil, Hong Kong, Taiwan and Indonesia contributing samples and analyses, according to a summary from the University of the Ryukyus. The authors recommend expanded monitoring and genomic sampling to track where zoantharians are most likely to spread as oceans continue to warm.
What Comes Next
Press coverage and the study’s release emphasize that this new atlas is meant as a starting line for managers and scientists trying to forecast what reefs will look like in the future. More field work will be needed to nail down the ecological consequences of zoantharians’ unusual lifestyle, per a press release on EurekAlert!. For Hawaiʻi scientists, the results double as a reminder that small, easily overlooked creatures can have an outsized influence on how entire reefs reorganize under stress.
