Taxon classification Animalia Zoantharia Sphenopidae

Genus Palythoa Lamouroux, 1816

Type species.

Palythoa mammillosa (Ellis & Solander, 1786).

Description.

Colonial brachycnemic zoantharians with heavily sand-incrusted ectoderm and mesoglea. Occasionally solitary polyps are also seen.

Remarks.

Various authors have suggested to include the genus Protopalythoa Verrill, 1900 over the past century based on both morphological (Pax 1910, Ryland and Lancaster 2003) and molecular data (Burnett et al. 1997, Reimer et al. 2006a). Polyps of Palythoa are embedded in a well-developed coenenchyme (= “immersae”, Pax 1910) while those of Protopalythoa are more free and clear of the coenenchyme (= “intermediate” or “liberae”, Pax 1910). In this study, we consider Protopalythoa to be included within Palythoa . In general, polyps are firmly attached to stones or reef rocks. Currently, approximately 130 nominal species have been described ( Palythoa + Protopalythoa, Reimer 2014b, c) although some studies have suggested the presence of many synonyms (Burnett et al. 1997, Reimer et al. 2004, Reimer et al. 2012a). All described species are zooxanthellate with the exception of Palythoa macmurrichi (Haddon & Shackleton, 1891) (see Remarks below).