Today while diving in the South east of Bali, we got lucky to be welcome by ‘extremely’ cold temperature waters (21C, 69F). Because this is unusually cold water for Bali, it is actually a sign of upwelling of cold, clear water coming from the deep which is a sure sign of good visibility. So we took the opportunity to scan the deeper sandy area below the reef to see if we could find something interesting and boy we got lucky to find the very rare, solitary, free living, sand dwelling, Indophyllia macassarensis.
Indophyllia is closely related to true donut corals, Acanthophyllia and the highly vessicled Cynarina, all of which occur in nontypical reef environments. Due to its enigmatic nature, it took us few trial and error, to understand the exact location we should be looking for the Indophyllia colonies. Very open, flat sandy reef zones so far seem to be where free living, deep water species such as this one, call home, and where they can easily get food, and obviously where larvae will recruit.
We started to spot few Trachyphyllia geoffroyi by 24-25 m (70-75ft), and scanning the almost flat sandy bottom, covered with Sea Pen, Black corals, and other ahermatypic Nephtheidae (sfot corals) and we finally found the rare Indophyllia in 30 m (90 ft) of water. All by itself, in its own little private microhabitat.
Among the first in situ photography:
The reason why we were so happy to find this corals, is that probably these photos are among the first one of Indophyllia in situ. All the pictures in ‘Corals of the World’ from JEN Veron, are actually aquarium photos.
A problematic species:
This species is a bit like a myth, we’ve seen quite a few aquarium specimen, but never came across it underwater ourself.
This species looks very much like a hybrid of Cynarina lacrymalis and Acanthophyllia deshayesiana.
It has the size and wide fleshy appearance of Acanthophyllia deshayesiana with a mix of bubble type meaty mantle of Cynarina lacrymalis.
But while C. lacrymalis lives attached on the lower side, vertical surface of a rock. I. macassarensis is a free living coral, that inhabit sandy bottom, the same habitat as A. deshayesiana. The septa of I. macassarensis are thicker but shorter than C. lacrymalis.
Veron in Corals of the World, says that the skeleton is up to 45 mm, we can say that this one was much bigger, with at least 100 mm wide. With the total width of the tissues being around 250 mm or around 10 inches in diameter, and otherwise much the same size as A. deshayesiana. This sympatric group is a very interesting one, and a proper genetic analysis of the group should give very interesting information about these three species.
A very particular habitat:
The habitat where this solitary Indophyllia was found is a bowl shaped sandy bottom, that was collecting food from the surrounding waters and current. We were lucky to be in a huge school of sardines all along the time we were in this sandy bowl. This leads to us thinking that that place regularly concentrates zooplankton on which these coral feed.
All this information tells us that the ideal habitat for Indophyllia is very dim blue light, with very moderate flow, and it should be housed on a sand bottom, and regularly fed meaty food. Since wild corals from Indonesia are currently closed to collection, there is very little chance to find Indophyllia in the aquarium hobby except the occasional specimen from Malaysia, or perhaps it could turn up when exports begin in Papua New Guinea. We hope this insight into this very particular habitat will help aquarists properly maintain these beautiful corals, and share them to the next generation.