Shashank Keshavmurthy, Sung-Yin Yang, Ada Alamaru, Yao-Yang Chuang, Michel Pichon, David Obura, Silvia Fontana, Stephane De Palmas, Fabrizio Stefani, Francesca Benzoni, Angus MacDonald, Annika M. E. Noreen, Chienshun Chen, Carden C. Wallace, Ruby Moothein Pillay, Vianney Denis, Affendi Yang Amri, James D. Reimer, Takuma Mezaki, Charles Sheppard, Yossi Loya, Avidor Abelson, Mohammed Suleiman Mohammed, Andrew C. Baker, Pargol Ghavam Mostafavi, Budiyanto A. Suharsono, Chaolun Allen Chen

Stylophora pistillata is a widely used coral "lab-rat" species with highly variable morphology and a broad biogeographic range (Red Sea to western central Pacific). Here we show, by analysing Cytochorme Oxidase I sequences, from 241 samples across this range, that this taxon in fact comprises four deeply divergent clades corresponding to the Pacific-Western Australia, Chagos-Madagascar-South Africa, Gulf of Aden-Zanzibar-Madagascar, and Red Sea-Persian/Arabian Gulf-Kenya. On the basis of the fossil record of Stylophora, these four clades diverged from one another 51.5-29.6 Mya, i.e., long before the closure of the Tethyan connection between the tropical Indo-West Pacific and Atlantic in the early Miocene (16-24 Mya) and should be recognised as four distinct species. These findings have implications for comparative ecological and/or physiological studies carried out using Stylophora pistillata as a model species, and highlight the fact that phenotypic plasticity, thought to be common in scleractinian corals, can mask significant genetic variation.