Dykning med Svampekoraller

Koh Lantas Marineliv | Fungiidae

Svampekoraller af familien Fungiidae er flade eller kuppelformede med runde eller ovale skeletter og en mulig central bue. Disse koraller er for det meste solitære og fritlevende (de er ikke fastgjort til underlaget), og de ses ofte ved alle koralrev på Koh Lanta-dykkerture.

De fleste svampekoraller er faktisk en enkelt, gigantisk polyp, nogle med flere munde. Nogle få arter danner faktisk små 'kolonier', hvor flere polypper lever inden for det samme, fælles skelet.

Alle arter har brede, spaltelignende munde med korte tentakler, som normalt strækkes ud for at spise om natten, undtagen solsikkekorallen (Heliofungia actiniformis), som har meget lange tentakler, der strækkes ud om dagen og ofte forveksles med en søanemone.

Fritlevende individer kan bevæge sig, men meget langsomt. Det gør de ved at puste vævet op og tømme det for luft. Mens mindre dyr kan rette sig selv op, hvis de ved et uheld bliver væltet, vil større dyr dø, hvis det sker for dem.

Unge svampekoraller starter deres liv med at sidde fast på en hård overflade og ligner faktisk en lille svamp med stilk. Efterhånden som korallerne modnes, bryder de hos de fleste arter af med deres stilk og lever som voksne uden at være fastgjort til bunden. Hos nogle få arter forbliver den voksne koral fastgjort, og stilken skjules af den voksende skive.

3 arter fundet på denne side:

Elongate Mushroom Coral (Ctenactis echinata)
Common Mushroom Coral (Fungia fungites)
Tongue Mushroom Coral (Herpolitha limax)

Elongate Mushroom Coral

(Ctenactis echinata)

Ctenactis echinata @ Koh Haa

The Elongate Mushroom Coral has an oblong-oval shape and is usually brownish, but may also be greenish.

This species is not colonial (it only has a single polyp/mouth) and is free living, with a dominant axial furrow.

The upper side has large, toothed costate septa (a septa is one of the radiating vertical plates within the corallite wall. When it extends beyond the coralite wall, it is called the costate). The underside has numerous pointed tips.

The Elongate Mushroom Coral can grow up to 25 cm long, and is common to all dive sites around Koh Lanta.

Common Mushroom Coral

(Fungia fungites)

Fungia fungites @ Koh Haa

The Common Mushroom Coral has a circular coral plate, occasionally with an arched center. The septal teeth are triangular and pointed.

The tentacles are short and bubble-shaped. The colour may vary from greyish-green to yellowish-brown to pink.

The Common Mushroom Coral is often seen solitary, or in small groups, usually in shallower areas. This single coral polyp can grow to 28 cm, but is usually observed 5 cm to 15 cm.

Tongue Mushroom Coral

(Herpolitha limax)

Herpolitha limax @ Koh Haa

The Tongue Mushroom Coral, also known as the Slipper Coral or Boomerang Coral, is a colonial, free-living mushroom coral, with many polyps living within a single colony.

Colonies may be flat or domed, and are usually elongate, with rounded ends. Colonies may also be Y, T or X shaped.

Tongue Mushroom Coral axial furrow with slit-like mouths

The Tongue Mushroom Coral has an indistinct axial furrow which runs most of the length of the colony, and contains multiple irregularly spaced slit-like mouths.

There are many smaller secondary mouths occurring outside the axial furrow. Septa costae are arranged in rows perpendicular to the colony edge and have regular, densely packed teeth which are interrupted by the numerous secondary mouths.

Tongue Mushroom Coral many secondary mouths

The white-tipped 'tentacles' along the costate septa rows are short and partially transparent. These are not true tentacles but inflated portions of the costate septa tissues. The true colony feeding tentacles are extended at night.

The Tongue Mushroom Coral grows to 50 cm, but more commonly observed around 20 - 30 cm at the dive sites around Koh Lanta.

This species may be pale or dark brown, or greenish-brown and is found on reef slopes.