Koh Chang Invertebrate Species

Banded Sea Urchin

Posted on by Dave in Koh Chang Invertebrate Species, Koh Chang Starfish, Koh Chang Wildlife Species Leave a comment

Banded Sea Urchin (Echinotrix calamaris)

Image Copyright BB Divers

Image Copyright BB Divers

Observed: Koh Chang Reefs, December 2015
Observed By: BB Divers

Watch out for the sharp and brittle spines of the banded sea urchin. A trailing hand or foot that brushes against them will cause them to break off in the flesh and despite having no poison they can easily cause infection and are the very devil to remove.

The spines of the sea urchin radiate from a roundish shell that forms their endoskeleton and protects the urchin from predators. Like their close relatives the startfish sea urchins exhibit five fold symmetry with five equal-sized body parts radiating out from a central point.

Banded Sea Urchin Wikipedia

 

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Murex Shell

Posted on by Dave in Koh Chang Invertebrate Species, Koh Chang Mollusc Species, Koh Chang Wildlife Species Leave a comment

Murex Shell (Jorunna fenebris)

Image Copyright BB Divers

Image Copyright BB Divers

Observed: Koh Chang, December 2015
Observed By: BB Divers

The Muricidae are a family of sea snails that have charecteristic shells with elaborate protective spines protruding from them.

The majority of this family are carnivores that feed on smaller species of shells which they gain access to by boring through the shells and sucking out the soft contents (pause for a shudder!)

Muricidae Wikipedia

 

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Dotted Nudibranch

Posted on by Dave in Koh Chang Invertebrate Species, Koh Chang Mollusc Species, Koh Chang Wildlife Species Leave a comment

Dotted Nudibranch (Jorunna fenebris)

Image Copyright BB Divers

Image Copyright BB Divers

Observed: Koh Chang, December 2015
Observed By: BB Divers

The dotted nudibranch is a white-bodied species of nudibranch with distinctive black rings filled with black and white spots.

Dotted Nudibranch Wikipedia

 

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Phyllidia Ocellata

Posted on by Dave in Koh Chang Invertebrate Species, Koh Chang Mollusc Species, Koh Chang Wildlife Species Leave a comment

Phyllidia Ocellata

Image Copyright BB Divers

Image Copyright BB Divers

Observed: Koh Chang, December 2015
Observed By: BB Divers

This strange mollusc is a type of nudibranch that has a bright yellow body that is covered with lumpy white tubercules. It can measure up to 6cm in length, which is probably quite enough. At that length it is cute and colourful – but you probably wouldn’t think that if it was six metres long would you?

Phyllidia Ocellata Wikipedia

 

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Pharoah Cuttlefish

Posted on by Dave in Koh Chang Invertebrate Species, Koh Chang Mollusc Species, Koh Chang Wildlife Species Leave a comment

Pharoah Cuttlefish (Ostracion cubicus)

Image Copyright BB Divers

Image Copyright Jonathan Milnes

Image Copyright BB Divers

Image Copyright Jonathan Milnes

Observed: Koh Chang Reefs, December 2015
Observed By: Jonathan Milnes

The Pharoah Cuttlefish is a large species of cuttlefish that grows up to 42cm in length and 5kg in weight. It is of course a mollusc and not a fish – it has no bone instead having a skeleton made out of a shell known as the cuttlebone.

Cuttlefish are all round  marvellous animals- here are a few reasons  why:
– For a start they are one of the most intelligent invertebrate species with a level of intelligence that has been compared to that of a dog.

– Also like their close relatives the squid they fire out clouds of ink to help them to escape from predators.

– Then there are their eyes, which work in a completely different way to those of vertebrates. So different in fact that these two different eye types are considered to be examples of convergent
evolution
, the separate development of biological organs that perform the same role.

– And there is their skin colour and texture-changing abilities. They can rapidly change their skin colour at will using special skin cells called chromatophores, iridphores and leucophores (read the Wikipedia page it’s fascinating). They use this to camouflage themselves when hunting prey but also in wild technicolour mating and territorial displays that are, frankly, amazing.

– Oh, and they have beaks. And they swim backwards. And their blood is green and they have three hearts. And they are colourblind. And they taste food with their suckers.

Pharoah Cuttlefish Wikipedia

 

 

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Colour Sergeant

Posted on by Dave in Koh Chang Butterflies and Moths, Koh Chang Insects, Koh Chang Invertebrate Species, Koh Chang Wildlife Species Leave a comment

Colour Sergeant (Athyma nefte)

Image Copyright สุธนัย ครุพานิช

Image Copyright สุธนัย ครุพานิช

Image Copyright สุธนัย ครุพานิช

Image Copyright สุธนัย ครุพานิช

Observed: Koh Chang, December 2015
Observed By: สุธนัย ครุพานิช

The colour sergeant is a species of brush-footed butterfly with black wings that have a white and an orange stripe. You can’t see that here though since we only have observations of the weid and worderful juvenile caterpillar form.

As you can see this is a many-horned and spiky little creature that exudes all kinds of tendrils and feelers.

Colour Sergeant Wikipedia

 

 

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Spotted Hermit Crab

Posted on by Dave in Koh Chang Crustacean Species, Koh Chang Invertebrate Species, Koh Chang Wildlife Species Leave a comment

Spotted Hermit Crab (Dardanus megistos)

spotted hermit crab at koh chang

Image Copyright BB Divers

hermit-crab-dardanus-megistos-bbd-2015-86

Image copyright BB Divers

Observed: Koh Chang Reefs, 2015
Observed By: BB Divers

The hermit crab is a great opportunist. Let’s face it it’s hard work being a crab. Your shell doesn’t grow and you do – so then you have to lose the old shell and wait around for ages while your new one hardens. and in the meantime you’re not protected from all the feasting beasts of the reef.

Why not just nick one?

So the hermit crab just grabs one of the many uninhabited mollusc shells that lie around and moves in. When it gets too small simply move to a new shell. Too easy!

Spotted Hermit Crab Wikipedia

 

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Rusty Gorgonian

Posted on by Dave in Koh Chang Corals and Anemones - Cnideria, Koh Chang Invertebrate Species, Koh Chang Wildlife Species Leave a comment

Rusty Gorgonian (Alyconacea)

rusty gorgonian coral at koh chang

Image Copyright BB Divers

Observed: Koh Chang Reefs, 2015
Observed By: BB Divers

The rusty gorgonian is a brightly coloured member of the same coral family as the sea whips and sea fans. These corals grow in long and delicate filaments.They are a popular aquaruim coral.

Apparently there are over 500 species of Gorgonians, and whilst this one looks very much like the rusty one but I wouldn’t bet my house on it!

Gorgonians Wikipedia

 

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Robust Staghorn Coral

Posted on by Dave in Koh Chang Corals and Anemones - Cnideria, Koh Chang Invertebrate Species, Koh Chang Wildlife Species Leave a comment

Robust Staghorn Coral (Acropora robusta)

robust staghorn coral at koh chang

Image Copyright BB Divers

Observed: Koh Chang Reefs, 2015
Observed By: BB Divers

Another case of clear, almost tautological species naming is the Robust staghorn coral. This is a coral that looks very much like a stag’s horns, and a robust stag at that.

It is a species of stony coral that is common throughout the Indo-Pacific region. Its main predator is that great enemy to corals and reefs the crown-of-thorns sea star, boo hiss.

Robust Staghorn Coral at What’s That Fish

 

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Magnificent Sea Anemone

Posted on by Dave in Koh Chang Corals and Anemones - Cnideria, Koh Chang Invertebrate Species, Koh Chang Wildlife Species Leave a comment

Magnificent Sea Anemone (Heteractis magnifica)

magnificent sea anemone at koh chang

Image Copyright Jonathan Milnes

magnificent sea anemone at koh chang 2

Image Copyright Jonathan Milnes

Observed: Koh Chang Reefs, 2015
Observed By: Jonathan Milnes

It’s probably stating the obvious but the Magnificent Sea Anemone is, well, magnificent.

It is a huge and brilliantly purple coloured anemone that can have a diameter of up to one metre.
As with many species of anemone the magnificent sea anemone has symbiotic relationships with anemonefish – which protect the anemones from predation in return for the protective environment of the anemone’s stinging tentacles. This species hosts twelve different species of anemonefish.

Magnificent sea Anemone Wikipedia

Other Koh Chang Corals and Anemones

 

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