Palythoa


Palythoa is a genus of anthozoans in the order Zoantharia.

Description

The polyps of Palythoa are partially embedded in an encrusting mat of tissue covering the substrate on which the colony grows. The individual polyps have flattened oral discs surrounded by a fringe of tentacles. The tentacles' shape and size can vary considerably between species, and even between colonies of the same species. Their colors are also highly variable, with relatively dull shades like cream, coffee, white, brown, or yellow, being the most common. Fluorescent colored colonies also exist, but these are more rare.

Palytoxin

Palytoxin is a highly toxic fatty alcohol produced by many species of Palythoa, and is also found in other corals and certain marine invertebrates. The substance was first isolated from the seaweed-like "limu-make-o-Hana" in 1971 in Hawaii. Scientific investigation of the seaweed found it to be a colonial cnidarian, which was classified as a zoanthid and named Palythoa toxica. Small quantities of palytoxin can be fatal should it be ingested or inhaled.
The presence of this toxin is of significance to aquarists who keep reef aquariums, as Palythoa and related zoanthids are commonly kept as decorative specimens in marine aquaria. Aquarists have reported symptoms consistent with palytoxin poisoning prior to having exposure to zoanthids suspected to contain the toxin. One report involved an aquarist being accidentally poisoned through skin injuries after handling zoanthids. Another report involved an aquarium hobbyist in Virginia who experienced a severe respiratory reaction after trying to eradicate colonies of brown zoanthids from rocks in their aquarium. A 2010 study found that a single specimen of Palythoa from a sample of fifteen colonies purchased from three aquarium stores in the Washington D.C. area contained high levels of palytoxin, indicating that toxic individuals are present in the captive population.
While poisoning events have occurred, they are exceedingly rare, and many reef hobbyists have kept Palythoa without any adverse reactions. However, it is generally recommended to always wear appropriate protective gloves and goggles when reaching into aquaria and handling animals which are suspected to be toxic.

Taxonomy and systematics

The genus Protopalythoa was once thought to be distinct from the genus Palythoa but is now considered to be a synonym.

Species

The following species are recognized in the genus Palythoa:Palythoa aggregata Lesson, 1830Palythoa anneae Carlgren, 1938Palythoa anthoplax Pax & Müller, 1957¹Palythoa arenacea Heller, 1868Palythoa argus Ehrenberg, 1834Palythoa aspera Pax, 1909Palythoa atogrisea Pax, 1924Palythoa australiae Carlgren, 1937¹Palythoa australiensis Carlgren, 1950Palythoa bertholeti Gray, 1867Palythoa brasiliensis Heider, 1899Palythoa braunsi Pax, 1924Palythoa brochi Pax, 1924Palythoa buitendijkl Pax, 1924Palythoa caesia Dana, 1846Palythoa calcaria Muller, 1883Palythoa calcigena Pax, 1924Palythoa calycina Pax, 1909Palythoa canalifera Pax, 1908Palythoa canariensis Haddon & Duerden, 1896Palythoa cancrisocia Martens, 1876Palythoa capensis Haddon & Duerden, 1896¹Palythoa caracasiana Pax, 1924Palythoa caribaeorum Palythoa ceresina Pax & Muller, 1956Palythoa chlorostoma Pax & Muller, 1956Palythoa cingulata Milne Edwards, 1857Palythoa clavata Palythoa complanata Carlgren, 1951¹Palythoa congoensis Pax, 1952Palythoa dartevellei Pax, 1952Palythoa densa Carlgren, 1954¹Palythoa denudata Dana, 1846Palythoa dura Carlgren, 1920Palythoa durbanensis Carlgren, 1938¹Palythoa dysancrita Pax & Muller, 1956Palythoa eremita Pax, 1920Palythoa fatua Schultze, 1867Palythoa flavoviridis Ehrenberg, 1834Palythoa fuliginosa Dana, 1846Palythoa fusca Palythoa glareola Palythoa glutinosa Duchassaing & Michelotti, 1864Palythoa grandiflora Palythoa grandis Palythoa gregorii Haddon & Duerden, 1896Palythoa gridellii Pax & Muller, 1956Palythoa guangdongensis Zunan, 1998¹Palythoa guinensis von Koch, 1886¹Palythoa haddoni Carlgren, 1937¹Palythoa halidosis Pax, 1952Palythoa hartmeyeri Pax, 1910Palythoa heideri Carlgren, 1954¹Palythoa heilprini Palythoa heliodiscus Palythoa horstii Pax, 1924Palythoa howesii Haddon & Shackleton, 1891¹Palythoa hypopelia Pax, 1909Palythoa ignota Carlgren, 1951Palythoa incerta Carlgren, 1900Palythoa insignis Carlgren, 1951Palythoa irregularis Duchassaing & Michelotti, 1860Palythoa isolata Verrill, 1907Palythoa javanica Pax, 1924Palythoa kochii Haddon & Shackleton, 1891Palythoa leseuri Klunzinger, 1877Palythoa leucochiton Pax & Muller, 1956Palythoa liscia Haddon & Duerden, 1896Palythoa mammillosa Palythoa mizigama Irei, Sinniger & Reimer, 2015Palythoa monodi Pax & Muller, 1956Palythoa multisulcata Carlgren, 1900¹Palythoa mutuki Palythoa natalensis Carlgren, 1938Palythoa nelliae Pax, 1935Palythoa nigricans McMurrich, 1898Palythoa oorti Pax, 1924Palythoa psammophilia Walsh & Bowers, 1971Palythoa senegalensis Pax & Muller, 1956Palythoa senegambiensis Carter, 1882Palythoa shackletoni Carlgren, 1937Palythoa sinensis Zunan, 1998¹Palythoa singaporensis Pax & Müller, 1956¹Palythoa spongiosa Andres, 1883Palythoa stephensoni Carlgren, 1937¹Palythoa texaensis Carlgren & Hedgpeth, 1952Palythoa titanophila Pax & Müller, 1957¹Palythoa toxica Walsh & Bowers, 1971Palythoa tropica Carlgren, 1900Palythoa tuberculosa Palythoa umbrosa Irei, Sinniger & Reimer, 2015Palythoa variabilis Palythoa vestitus Palythoa wilsmoorei Wilsmore¹Palythoa xishaensis Zunan, 1998¹Palythoa yongei Carlgren, 1937¹Palythoa zanzibarica Carlgren¹
¹Indicates Species Unreviewed: has not been verified by a taxonomic editor
Taxon inquirendum:
  • Palythoa anduzii
  • Palythoa auricula
  • Palythoa brevis Andres, 1883
  • Palythoa casigneta Walsh, 1967
  • Palythoa distans
  • Palythoa dubiae Walsh, 1967
  • Palythoa eupaguri Marion, 1882
  • Palythoa fulva Walsh, 1967
  • Palythoa fulva
  • Palythoa gigantea Cubit & Williams, 1983
  • Palythoa glomerata Marion, 1882
  • Palythoa lutea
  • Palythoa mcmurrichi
  • Palythoa olivascens Brandt, 1835
  • Palythoa plana
  • Palythoa vanikorensis
  • Palythoa viridifusca
  • ''Palythoa viridis''