Definition of Scleractinia in US English:


plural noun

  • An order of coelenterates that comprises the stony corals.

    Also called Madreporaria
    • ‘There is an emerging consensus that order Actiniaria (sea anemones) forms a monophyletic sister group to a clade comprising orders Scleractinia, Corallimorpharia, and Antipatharia, each of which appears to be monophyletic.’
    • ‘Molecular studies also indicate that extant Scleractinia and anemones probably have a common Paleozoic origin; i.e., these groups probably split in the late Paleozoic.’
    • ‘These include some Foraminiferida, Hydrozoa and Scleractinia, Bryozoa, Brachiopoda, Pelecypoda, Polychaeta, and Cirripedia.’
    • ‘Interestingly, the dominant modern coral group, the Scleractinia, took off at about the same time the dinoflagellates did.’
    • ‘During the early Mesozoic the Scleractinia steadily increased in numbers, diversity, and distribution culminating in extensive reef development in the Late Jurassic.’


Modern Latin (plural), from Greek sklēros ‘hard’ + aktis, aktin- ‘ray’.