Dykning med Fjerstjerner

Koh Lantas Marineliv | Articulata

Fjerstjerner findes på alle koralrev omkring Koh Lanta i en række forskellige farver, herunder sort og hvid, pink, lilla, gul, hvid og orange. Nogle arter har flere farver og mønstre.

Fjerstjerner, også populært kaldet søliljer, starter livet med en stilk eller stængel, som de smider, når de bliver voksne. Som voksne har de normalt mellem 5 og 40 arme, afhængigt af arten, og de kan regenerere tabte eller beskadigede arme, ligesom søstjerner.

De fjerformede arme kaldes pinnuler, og pinnulerne krøller sig sammen, når fjerstjernen hviler, og spreder sig ud, når den søger føde eller svømmer. Cirri er små ben for enden af pinnules, som hjælper med at fastgøre dem til underlaget.

Ligesom andre pighuder har fjerstjerner radial symmetri med munden placeret i midten, og de lever af bittesmå organismer som plankton og havaffald ved at sprede deres arme i en vifteform.

2 arter fundet på denne side:

Noble Feather Star (Comaster Nobilis)
Variable Bushy Featherstar (Comaster schlegelii)

Noble Feather Star

(Comaster Nobilis)

Comaster nobilis @ Koh Bida

Sometimes known as the Yellow Feather Star, this species may occur in a number of colour variations, but usually has 35 - 40 yellow arms. There are sometimes black, green, or white speckles on the under surface close to the centre.

The Noble feather star feeds on detritus, phytoplankton and zooplankton. The larvae of this feather star swim freely with plankton for a few weeks, then they settle down growing into a stalked form. Mature specimens break the stalk becoming free-living.

The Comaster nobilis has a wide range, occurring throughout the Indo-Pacific region.

Variable Bushy Featherstar

(Comaster schlegelii)

Comaster schlegelii @ Koh Bida

The variable bushy feather star has five rays attached to the upper part of the body, each subdivided into a number of feathery arms called pinnules. When one of these is lost, two grow in its place.

The colour is very variable, some specimens being plain golden yellow, pale brown or black and others being multicoloured, often green with bands of orange, white and black on the arms and pinnules.

They are most commonly found in the shallowest areas of the reef, usually down to around 5 m.

Juveniles often keep their body concealed in a crevice, with the only visible part being its array of arms.

On the underside of the body are about twenty claw-like appendages known as cirri which are used to cling on to the underlying surface, but they are lost in older specimens, which attach directly using the underarms.