A new paper on the phylogeny and the evolution of zoanthid growing forms has identified a new species of Hydrozoanthus, and a completely new genus and accompanying species called Aenigmanthus segoi. While in the aquarium hobby we are mostly focused with the shallow water, photosynthetic Zoanthus, Palythoa and their relatives there’s a whole world of zoanthids with a wide range of different growth forms.
One of the most common of these is what’s called ‘epizootic’ meaning simply that these zoanthids grow on top of other creatures, notably gorgonians and especially hydroids. The newly described Hydrozoanthus sils is an example of a zoanthid that has to grow on the structure created by feather like hydroids. When the hydroid is fully encrusted the small polyped red bodied Hydrozoanthus sils looks more like a gorgonian than a zoanthid.
Another group of epizootic zoanthids can grow on the structure created by other marine life but they don’t have to. Furthermore, some of these will accumulate sand grains and other particles between the polyps giving the overgrown branches a ‘dirty’ appearance as is the case with the new genus & species Aenigmanthus segoi.
The new species and new genus are described by Hiroki, Takahiro & Reimer in the newest edition of Molecular Phylogenetics & Evolution.