The beauty of sea anemones

10 June 2019 | Research - In Focus

Sea anemones are common animals in many marine habitats, but the identities and classification of most tropical species remain poorly established. For the first time in over a century, NUS researchers were able to re-establish the identity of a Phymanthus sea anemone.

The photograph above shows the Frilly sea anemone (Phymanthus pinnulatus) during a low spring tide, extending its brilliant electric blue tentacles from within a hidden rocky crevice, to feed.

Of the 11 Phymanthus species known worldwide, the Frilly sea anemone is the least understood. The very first specimen was collected from Singapore in the early-1860s by German zoologist Eduard von Martens, during his expedition around maritime Southeast Asia to document its biodiversity. In 1877, CB Klunzinger described the specimen that he chanced upon at the Museum für Naturkunde, Berlin, while von Martens was the curator there. However, the description was no more than a brief, two-sentence footnote that lacked illustrations and crucial details to identify it.

To re-establish this sea anemone’s identity, NUS Biological Sciences doctoral student Mr Nicholas Yap studied the original specimen kept in Berlin, characterising its external and internal anatomy, and compared it to over 50 fresh specimens collected from Singapore’s shores. He also examined other Phymanthus sea anemones found in the Southeast Asian region to distinguish the species and ascertain its geographic range.

Mr Yap’s work produced detailed illustrations and descriptions necessary to identify the animal. Furthermore, the data suggest that several other Phymanthus species found in the region have been wrongly identified, prompting further research to disentangle the confused classification of these sea anemones. The findings were reported in the journal ZooKeys on 17 April 2019.

Unlike corals, basic biodiversity research on sea anemones has been scant, hampering efforts for applied research. This work opens up new research opportunities, such as the study of novel bioactive compounds produced by sea anemones.