Published records of mesophotic zooxanthellate corals from Rapa Nui (Easter Island) are rare and so far based only on dredged specimens and observations during scuba dives (Wells 1972, Glynn et al. 2003, 2007). During recent remotely operated vehicle (ROV) surveys off Rapa Nui (March 2016), a large and dense aggregation of zooxanthellate Cycloseris corals (Scleractinia: Fungiidae) with a density of approximately 500 ind m−2 was discovered (27°08 ́55 ̋S, 109°26 ́46 ̋W) on black sand in a depth range of approximately 79–85 m (Panels A, B). A few corals were overturned, exposing their white (azooxanthellate) undersides and sutures along which self-fragmentation took place (Panel C, arrows). The Cycloseris field was video-recorded on 17 March, 2016, with a high-resolution camera, equipped with two red parallel laser beams for size calibration (see Online Supplementary Video). More than 95% of the corals showed autotomy and regeneration, similar to fields dominated by Cycloseris distorta (Michelin, 1842) in the Galápagos Islands (Feingold 1996, Hickman 2008, Glynn et al. 2018) and by Cycloseris fragilis (Alcock, 1893) in the Persian Gulf (Hoeksema et al. 2018).
Scleractinia (Hard Corals)
Remotely Operated Vehicle (ROV)