sea anemones text index | photo index
Phylum Cnidaria > Class Anthozoa > Subclass Zoantharia/Hexacorallia > Order Actiniaria
Leathery anemone
Radianthus crispa
Family Stichodactylidae
updated Jul 2024
Where seen? This large anemone is sometimes seen on the reef edges of our Southern shores. According to Dr Fautin, it is sometimes seen living on branching corals. It was previously known as Heteractis cripsa.

Features: Diameter expanded 20-30cm, up to 50cm when fully expanded. Many long tentacles (about 10cm) that are snake-like, evenly tapered to a point often with coloured tips: mauve, blue, sometimes yellow or green. The tentacles may shrivel if the animal is disturbed. Body column with large, prominent, adhesive bumpy verrucae. The body column texture is leathery and it is uniformly coloured, usually grey. The oral disk is usually brownish violet or grey, rarely bright green, sometimes with white stripes.

Sometimes confused with other large sea anemones and similar large cnidarians. Here's more on how to tell apart large sea anemones with long tentacles and large 'hairy' cnidarians.

Leathery friends: The Leathery anemone harbours symbiotic algae (called zooxanthellae) that photosynthesize. The algae share the food produced with the anemone, which in turn provides the algae with shelter and minerals. Several kinds of animals may live happily among and unharmed by the tentacles of the anemone. These include the Peacock-tail anemone shrimp (Periclimenes brevicarpalis) and fishes such as Dascyllus trimaculatus and many species of anemonefishes.

Status and threats: As at 2024, it is listed as Endangered in Singapore.

Beting Bemban Besar, Apr 10

Tentacles may have coloured tips



Typical bumpy prominent verrucae
on the body column.

An anemone shrimp was seen in this one.

Leathery anemone (Heteractis crispa)

Leathery anemones on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores


Bleaching.
Kusu Island, Jun 10
Photo shared by Loh Kok Sheng on his blog.

Kusu Island, Jun 10
Photo shared by Loh Kok Sheng on his blog.

Kusu Island, May 10
Photo shared by Marcus Ng on his flickr.


Pulau Jong, Jun 12
Photo shared by Loh Kok Sheng on his blog.


Bleaching
Pulau Tekukor, May 10
Photo shared by Loh Kok Sheng on his blog.

Bleaching.
Pulau Tekukor, Jun 16
Photo shared by Loh Kok Sheng on facebook.


Pulau Hantu, May 19


Photo shared by Loh Kok Sheng on facebook.


Pulau Semakau, Jul 20
Photo shared by Loh Kok Sheng on facebook.

Pulau Semakau, Jul 20


Pulau Semakau, Aug 07

Photo shared by Loh Kok Sheng on his flickr.

Pulau Semakau, Jan 09
Photo shared by Marcus Ng.

Pulau Semakau (North), Jun 18

Photo shared by Liz Lim on facebook.


Bleaching.
Terumbu Semakau, Jun 10
Photo shared by Toh Chay Hoom on her blog.

Bleaching.


Terumbu Semakau, Jun 22
Photo shared by James Koh on facebook.

Terumbu Semakau, Jun 10
Photo shared by Loh Kok Sheng on his blog.



Terumbu Raya, Feb 23
Photo shared by Loh Kok Sheng on facebook.


Terumbu Raya, Mar 09

Photo shared by Loh Kok Sheng on his flickr.

Terumbu Raya, Jun 15

Photo shared by Loh Kok Sheng on his blog.

Terumbu Raya, May 24

Photo shared by Jonathan Tan on faceook


Terumbu Bemban, Jul 11

Photo shared by Loh Kok Sheng on his blog.

Terumbu Bemban, Apr 11

Photo shared by Russel Low on facebook.


Beting Bemban Besar, May 11
Photo shared by Loh Kok Sheng on his blog.

Beting Bemban Besar, Mar 20
Photo shared by Abel Yeo on facebook.

Beting Bemban Besar, May 10
Photo shared by Marcus Ng on flickr.


Pulau Senang, Jun 10

Photo shared by Loh Kok Sheng on his flickr.

Pulau Senang, Jun 10
Photo shared by Loh Kok Sheng on his flickr.

Links

References

  • Checklist of Cnidaria (non-Sclerectinia) Species with their Category of Threat Status for Singapore by Yap Wei Liang Nicholas, Oh Ren Min, Iffah Iesa in G.W.H. Davidson, J.W.M. Gan, D. Huang, W.S. Hwang, S.K.Y. Lum, D.C.J. Yeo, 2024. The Singapore Red Data Book: Threatened plants and animals of Singapore. 3rd edition. National Parks Board. 258 pp.
  • Daphne Gail Fautin, S. H. Tan and Ria Tan. Dec 2009. Sea anemones (Cnidaria: Actiniaria) of Singapore: abundant and well-known shallow-water species. The Raffles Bulletin of Zoology. Pp. 121-143.
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