Saturday, May 16, 2009

Intertidal Echinoderms of Bali

During our Bali trip, we managed to spend 2 days at Sanur, which has a huge intertidal area with lots of seagrasses and animals. Since my favourite animal group are the echinoderms, I will highlight some of the ones we saw there before writing about the other animals :)

Knobbly Sea Star (Protoreaster nodosus)
The Knobbly Sea Star (Protoreaster nodosus) is very abundant on some parts of the intertidal area. I totally lost count of the number of knobblies I saw.

Luzon Seastar (Echinaster Luzonicus)
The Luzon Sea Star (Echinaster Luzonicus) is quite common here. I saw this while diving too.

Luzon Sea Star (Echinaster Luzonicus)
Here's another colour variation.

Not exactly sure what sea star this is. We found 2 of them, both hidden under rocks. The closest match is Linckia multiflora, but the pattern is somewhat different from previous specimens I have seen, and is much bigger, so can't really say for sure.

Sea Star
Yet another unidentified sea star, though I thought it looked like a juvenile Asteropsis carinifera.

probably Linckia laevigata
This is probably a Linckia laevigata, but the pattern on its aboral side looks somewhat different, so can't really say for sure. Or perhaps the pattern is different because this is a juvenile?

Sea Star (Gomphia gomphia)
Looks like a Gomphia gomphia to me. We found a few of these among the seagrasss and the coral rubble.

Pink brittle star
A very pretty pinkish brittle star which is very common here.

Black Long-spined Sea Urchin (Diadema setosum)
Black Long-spined Sea Urchin (Diadema setosum) were also very common, gathering in masses in the tidal pools. It can be differentiated from similar looking species with the orange ring on the anal cone, and 5 lines of blue dots radiating from it, though at night whitish lines may appear at where the blue dots are, making them less obvious.

Savigny's Sea Urchin (Diadema savignyi)
A similar looking sea urchin is the Savigny's Sea Urchin (Diadema savignyi) with a bluish ring surrounding the anal cone, and 5 solid lines radiating from it.

Double Spined Sea Urchin (Echinothrix calamaris)
We found several Double Spined Sea Urchin (Echinothrix calamaris) in the tidal pools too. This sea urchin has 2 distinctly different types of spines - thicker ones (usually with stripes) and thinner and shorter ones. It usually has 5 greenish lines radiating from the balloon-like anal cone.

Black Diadema Sea Urchin (Echinothrix diadema) with commensal shrimps (Stegopontonia commensalis)
This is probably a Black Diadema Sea Urchin (Echinothrix diadema), which may resemble the darker variations of D. calamaris sometimes. However, this sea urchin lacks the balloon-like anal cone, and instead has a small black anal cone. The one above happened to have 2 small commensal shrimps (Stegopontonia commensalis) with it. Can you spot them?

Red Sea Urchin (Astropyga radiata)
We also found one Red Sea Urchin (Astropyga radiata).

Cake Sea Urchin (Tripneustes gratilla)
The Cake Urchin (Tripneustes gratilla) is another sea urchin with really pretty colours. The pretty colours, however, also acts as a warning telling predators that it is venomous.

Cake Sea Urchin (Tripneustes gratilla)
This is probably another colour variation of the Cake Urchin or a Mespilia globulus. But photos of the latter that I found online appear to have more neatly arranged spines though, so I think it's more likely to be the former.

Sea Urchin
Not quite sure which species this sea urchin is though.

Flower Sea Urchin (Toxopneustes pileolus)
This very pretty Flower Sea Urchin (Toxopneustes pileolus) is actually one of the most venomous sea urchins in the world, with the flower shaped pedicellaria being able to give extremely painful and sometimes lethal stings.

Matha's Sea Urchin (Echinometra mathaei)
The Matha's Sea Urchin (Echinometra mathaei) was very abundant here, but most of the time they were hiding in crevices or under rocks.

Synaptid Sea Cucumber (Family Synaptidae)
Interestingly, the only sea cucumbers we found at Sanur were Synaptid Sea Cucumbers (Family Synaptidae). In fact, I also did not see any sea cucumbers while diving in Bali. Kind of different from the dives I have done in Malaysia, where there are lots of sea cucumbers. The only other sea cucumber we saw in Bali was not in Sanur, but in Kuta, where we found several Lollyfish Sea Cucumbers.

Lollyfish sea cucumber, Holothuria (Halodeima) atra
This is one of the Lollyfish Sea Cucumbers [Holothuria (Halodeima) atra] we saw at Kuta.

Keyhole Sand Dollar
At Kuta, we also found several Keyhole Sand Dollars (Family Mellitidae). Not sure of the species though.

Indeed, Bali, especially Sanur, is certainly a great place to spot echinoderms. You don't even have to dive to see all these!


Anonymous said...

I've subscribed to tide chaser for several months now and am forever facinated with the pictures and and commentary. I'm a bird watcher and have enjoyed tide pools on occasion on the US Pacific coast, but never have traveled specifically to see intertidal creatures.

Thanks for taking the time to post this for the rest of the world to see.

Illinois, USA

Ron Yeo said...

Hi Rick,

Glad to hear that you enjoyed reading my blog :)


:) Ron