The Synatid sea cucumber in Semakau is…

The large and long synatid sea cucumber that we often see feeding among the seagrass has an ID, or at least, is narrowed to the genus level.

This sea cucumber is commonly found in the tape seagrass bed of Pulau Semakau. We can safely confirmed it as Opheodesoma sp. based on the two distinctive shapes of the ossicles or skeletons below which were extracted from the body wall.

In case anybody ask, this was taken from a microscope, taken at x40 magnification. Each type of ossicle has a name, and this is called an anchor plate.

While is known as, well, an anchor. If you touch this cucumber, you can feel that it is ‘sticky’ and the reason for that is because of the hooks from these anchors.

The reason why I find it harder to ID Synatidae is because, firstly, I can’t rely much on its external morphology, since the colour seems variable for this family of sea cucumbers, and secondly, the sweet corn-like surface of the sea cucumber might not be present on the same species with a different form or variety.

The only Opheodesoma recorded in Singapore is Opheodesoma grisea. While most of the description fits, I will prefer not to assume its identity, at least not until I have looked at all the descriptions from other species in this genus. But we can just call it Opheodesoma c.f. grisea if we really want to force it in. haha~

There are ten species of Opheodesoma at the moment. I guess when I have more time, I should probably be able to get its species by finding more keys for all the species and extracting the ossicles from other parts of the body besides the main body wall.

One thing to note is that Dr David Lane had identified another similar cucumber in the ‘The Story of Semakau Landfill’ book as Synapta maculata. Will love to get my hands on the specimen if it is available somewhere for a comparison. No matter what, from my knowledge, this species was never recorded in other literature and is possibly a new record.