The zooxanthellate scleractinian coral Oulastrea crispata, a widely distributed species across central Indo-Pacific nearshore marine habitats, has been first reported from the Mediterranean Sea (Corsica) in 2014.

This study reports on two new sites for this species in the NW Mediterranean Sea and provide a general description of external morphological characters of the colonies and a detailed account of the cnidom to help future identifications.

The authors state that living specimens may appear virtually identical to small colonies of the Mediterranean zooxanthellate scleractinian Cladocora caespitosa. However, it is underlined that while this species shows long, ramified, independent corallites, with cylindrical calices, O. crispata has enlarged, cup-like calices, which can be joined by the coenostreum. Both species also show clear differences among several groups of nematocysts.

The authors highlight that identifications based on underwater observations or even the analysis of photographs may easily lead to misleading identifications. In fact, it is hypothesized that O. crispata may have gone unnoticed because of misidentifications as C. caespitosa. The need for detailed research to get reliable maps of the actual distribution of this apparently non-indigenous species is stressed, as well as studies aimed at exploring the future role of O. crispata in Mediterranean photophilic communities.

Mariani et al. (2018) The zooxanthellate scleractinian coral Oulastrea crispata (Lamarck, 1816), an overlooked newcomer in the Mediterranean Sea? Mediterranean Marine Science 19:589-597.