hard corals text index | photo index
Phylum Cnidaria > Class Anthozoa > Subclass Zoantharia/Hexacorallia > Order Scleractinia > Family Merulinidae
Trumpet coral
Caulastraea sp.*
Family Merulinidae
updated Nov 2019
Where seen? These smooth pillows of hard corals with round to oval corallites are sometimes seen on some of our Southern shores. It was previously in Family Faviidae.

Features: The colony appears to be boulder-shaped, those seen 10-20cm or larger. But the colony is not solid (massive). The corallites are branching and trumpet-shaped (phaceloid): long narrow column flaring out at the top to a circular or oval shape (1-2.5cm diameter). The branching corallites may be packed closely to one another, or spaced apart. They are arranged with the broad, flared portions facing out so the colony forms an overall spherical shape. The tissue is fleshy, smooth, sometimes with bands in a contrasting colour. Tentacles many short, slender with bulbous tips. Tentacles are seldom seen. The circular or oval top of the corallite resemble eyes particularly when highlighted by the fleshy tissue. This results in common names such as bullseye coral and cat's eye coral. Colours seen include beige, brown, blue and greenish or purplish.

Hiding places: Usually hidden by the fleshy tissue, the 'hollow' structure of the branches provides hiding places for small animals deep within the coral.

Sometimes confused with some species of Lobed brain corals (Lobophyllia sp.) that may also have branching corallites with circular openings. Other corals that may appear similar include: Barabattoia and some Favia species. More on how to tell apart hard corals with big rings and fleshy tissue.

Status and threats: Caulastrea echinulata recorded for Singapore are listed as globally Vulnerable by the IUCN. Like other creatures of the intertidal zone, they are affected by human activities such as reclamation and pollution. Trampling by careless visitors, and over-collection also have an impact on local populations.

Kusu Island, May 04

Raffles Lighthouse, Jul 06
Tentacles peeping out.

Kusu Island, Jun 04

Beting Bemban Besar, Jun 09

Trumpet shaped corallites.

*Species are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience of display.

Trumpet corals on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Tanah Merah, May 13
Photo shared by Loh Kok Sheng on flickr.

Caulastrea species recorded for Singapore
Danwei Huang, Karenne P. P. Tun, L. M Chou and Peter A. Todd. 30 Dec 2009. An inventory of zooxanthellate sclerectinian corals in Singapore including 33 new records
**the species found on many shores in Danwei's paper.
in red are those listed as threatened on the IUCN global list.

  Family Merulinidae
Genus Caulastrea
  Caulastrea echinulata** (Vulnerable)
Caulastrea furcata**



  • Danwei Huang, Karenne P. P. Tun, L. M Chou and Peter A. Todd. 30 Dec 2009. An inventory of zooxanthellate sclerectinian corals in Singapore including 33 new records (pdf). Raffles Bulletin of Zoology Supplement No. 22: 69-80.
  • Veron, Jen. 2000. Corals of the World Australian Institute of Marine Science, Australia. 3 volumes.
  • Erhardt, Harry and Daniel Knop. 2005. Corals: Indo-Pacific Field Guide IKAN-Unterwasserachiv, Frankfurt. 305 pp.
  • Borneman, Eric H. 2001. Aquarium Corals: Selection, Husbandry and Natural History T.F. H Publications. 464 pp
links | references | about | email Ria
Spot errors? Have a question? Want to share your sightings? email Ria I'll be glad to hear from you!
wildfactsheets website©ria tan 2008