Of course, such broad generalities are inadequate when it comes to serious taxonomic study. Definitive identification requires examination of the microscopic calcium spicules which help to physically support these corals, and it’s here that we begin to see the crux of the problem. The spicules within the polypary of Sarcophyton are large and spindle-shaped, while those in the base are relatively thin and smooth. Compare this to Lobophytum, which has its polypary bearing squat, ovular sclerites and those within its stalk being thicker and bumpier. There is a third group, which has sclerites showing a mix of these features and a colony shape that can vary from toadstool-esque to those with an unfamiliar flattened form. These enigmatic intermediates, of which there are more than a dozen known, form a single clade at the base of this branch of coral life, suggesting that their confused morphology is likely the ancestral state in this group. One such coral, which appears to be commonly available in aquarium stores, is “Sarcophyton” ehrenbergi. If you google this name right now, you’ll find that this is one of the more popular taxonomies thrown about by aquarists. It would seem that just about every possible phenotype has now had this appellation attached to it, such that “ehrenbergi” has become the lingua franca of toadstool species identifications. But this coral is actually rather distinctive, in its own manner. Rather than having a flattened polypary which overhangs the stalk—visualize an actual mushroom here—“Sarcophtyon” ehrenbergi has more of a cup-like shape, with a stalk that gently expands into the thin perimeter of the polypary. Think of this as more of a vase than a toadstool. Larger specimens develop convolutions along this edge, giving a ruffled appearance to the coral.
Another distinctive phenotype in this intermediate clade can be seen in species like “Lobophytum” patulum, variatum & hseihi, which have a flattened shape with variably present fingers, lobes or ridges. There wouldn’t be much reason to confuse these with the typical Toadstool Coral, though they are nonetheless confusing. These are not the most eye-catching of soft corals, and I can’t recall ever seeing one available in the aquarium industry, though undoubtedly they have been. One for the true coral connoisseur, I suppose. Lastly, there are species like “Lobophytum” schoedei, mortoni, and sarcophytoides, which, as the name sarcophytoides should have hinted at, are very Sarcophyton-like. But, whereas in that genus the polypary is flattened or ruffled along the edges, the ruffled edges of these “Lobophytum” are more vertical and structured, being vaguely reminiscent of fingery species like Lobophytum hirsutum, one of the true Devil’s Hands. Again, these almost certainly show up now and then as aquarium exports, probably being innocuously sold as “Toadstool Corals”. It will likely be some time before these corals are formally revised and the intermediate clade is given a proper scientific name. Until then, these pseudo-toadstools are stuck in taxonomic limbo, and maybe the best way for aquarists to refer to these is with a common name. Seeing as none exists, allow me to coin one: the “False Toadstool Corals”. References
- Benayahu, Y. & L. M. Chou, 2010. On some octocorallia (Cnidaria: Anthozoa: Alcyonacea) from Singapore, with a description of a new Cladiella species. The Raffles Bulletin of Zoology, 58: 1–13.
- Benayahu Y., van Ofwegen L.P., Dai C.-F., Jeng M.-S., Soong K., Shlagman A., Hsieh H.J., McFadden C.S. 2012. Diversity, Distribution, and Molecular Systematics of Octocorals (Coelenterata: Anthozoa) of the Penghu Archipelago, Taiwan. Zool. Stud. 51: 1529-1548.
- Benayahu Y. & L. P. van Ofwegen, 2009. New species of Sarcophyton and Lobophytum (Octocorallia: Alcyonacea) from Hong Kong. Zoologische Mededelingen Leiden, 83: 863–876.
- McFadden, C.S., P. Alderslade, L.P. van Ofwegen, H. Johnsen & A. Rusmevichientong, 2006. Phylogenetic relationships within the tropical soft coral genera Sarcophyton and Lobophytum (Anthozoa, Octocorallia).— Invertebrate Biology 125: 288-305.
- Verseveldt, J., 1982. A revision of the genus Sarcophyton Lesson (Octocorallia, Alcyonacea).— Zoologische Verhandelingen Leiden 192: 1-91.
- Verseveldt, J., 1983. A revision of the genus Lobophytum von Marenzeller (Octocorallia, Alcyonacea).— Zoologische Verhandelingen Leiden, 200: 1-103.