A survey of pocilloporid corals and their endosymbiotic dinoflagellate communities in the Austral and Cook Islands of the South Pacific

It has recently been uncovered that the model reef coral Pocillopora damicornis is actually a taxonomic complex comprised of multiple species that are difficult to differentiate in situ. However, little is known about the distribution of these species across or within reef ecosystems. To better understand the spatial partitioning between the morphologically-similar sister species P. damicornis and P. acuta, 88 Pocillopora colonies were genotyped across five and three islands/atolls within the Austral and Cook Islands, respectively. A mix of newly described pocilloporid types was found across the two archipelagos, with nearly 33% of the specimens being identified not as the more commonly referenced a genotype of P. damicornis, but instead as P. acuta. Furthermore, P. damicornis was more likely to be found at depths greater than 15 m and in higher coral cover areas relative to P. acuta, suggesting that these closely-related species display distinct habitat preferences.