Cycloseris

Lore & Background

Corals in the genus Cycloseris are mostly solitary and free living, some attaining 10 centimetres in diameter. The discs are either round or oval, and the central mouth, surrounded by tentacles, may be a slit. The polyp sits in a calcareous cup, the corallite, and only extends its tentacles to feed at night. The septa are vertical skeletal elements inside the corallite wall, and the costae unite the septae at the base of the coral. In Cycloseris, both are thick but have fine teeth and are characteristic of the different species.

Cycloseris can be confused with specimens of the related genus Fungia, but the former are free living even as juveniles, while the latter bear a scar showing where they were attached when young. The genus was reclassified in 2012 to include some species that had previously been classified in the genus Coscinaraea, that are colonial with multiple mouths, in addition to the original species that are free living with a single central mouth.

The World Register of Marine Species lists extant species including Cycloseris boschmai, Cycloseris costulata, Cycloseris curvata, Cycloseris cyclolites, Cycloseris distorta, Cycloseris explanulata, Cycloseris fragilis, Cycloseris mokai, Cycloseris sinensis, Cycloseris somervillei, Cycloseris tenuis, Cycloseris vaughani, and Cycloseris wellsi. The Encyclopedia of Life lists extinct species such as Cycloseris brazzanensis, Cycloseris costulata, Cycloseris escosurae, Cycloseris hungaricus, Cycloseris lamellata, Cycloseris minuta, Cycloseris perezi, and Cycloseris striata.

Reader's Guide

Cycloseris is significant as a genus of solitary disc corals within the family Fungiidae, distinguished by its free-living habit even as juveniles, unlike the related genus Fungia which bears a scar from juvenile attachment. The genus tolerates turbid waters and inhabits lower reef slopes and soft sediment areas between reefs in the Indo-Pacific, indicating an ecological niche in less pristine conditions. Its reclassification in 2012 to include colonial species with multiple mouths from the genus Coscinaraea broadened the definition of Cycloseris, reflecting ongoing taxonomic refinement in coral systematics. The characteristic thick septa and costae with fine teeth are key to species identification. The listing of numerous extant and extinct species in authoritative registers underscores the genus's diversity and evolutionary history, with fossil records extending into the Eocene. The genus's ability to thrive in turbid environments and its morphological traits make it a subject of interest for understanding coral adaptation and taxonomy.