Invertebrate Systematics Invertebrate Systematics Society
Systematics, phylogeny and biogeography

Revision of methods for separating species of Protopalythoa (Hexacorallia : Zoanthidea) in the tropical West Pacific

John S. Ryland and John E. Lancaster

Invertebrate Systematics 17(3) 407 - 428
Published: 25 July 2003


The genus Protopalythoa Verrill, 1900 (family Sphenopidae) is defined and its status discussed. As with other zoanthid genera, species are difficult to separate by traditional methods. We have developed a rigorous approach to quantitative data derived from measurements and meristic characters. In support of genetic evidence, we have utilised the relationship between number of septa and polyp column diameter, and the capsule length of nematocysts (holotrichs and p-mastigophores), together with the presence or absence of basitrichs in the cnidom. Using this approach, the species Pr. mutuki (Haddon & Shackleton, 1891b) and Pr. heliodiscus, sp. nov. are separated, described and illustrated. Protopalythoa mutuki is interpreted as a normal micro-carnivore with autotrophic capability, while Pr. heliodiscus sp. nov. is an obligate autotroph with little ability to capture prey. The latter is the only zoanthid known to have vertical transmission of zooxanthellae.

Keywords: Australia, Great Barrier Reef, Fiji, taxonomy, meristic characters, cnidom, nematocyst capsules, Palythoa.

© CSIRO 2003

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