Is this the Ugliest Coral You Know? - On an Indicator Coral

[fishguy242]

There is some confusion with the fire corals (Millepora) which are best known for their stinging upon touch. Fire corals belong to another Class in another Subphylum of Cnidaria than Octocorallia (leather- and softcorals, blue coral) and Hexacorallia (stony corals, anemones).

Fire corals have "hairs" (stinging polyps) and digesting feeding polyps.

The blue coral Heliopora belongs to the Class Octocorallia and it seems very difficult to find a good image of the anatomy of a Heliopora or even just an Octocorallia polyp. What is typical for the anatomy of Octocorallia is eight feathered (pinnulate) tentacles while Hexacorallia always have six or a manifold of six (12, 24, ...) +/- smooth tentacles without pinnules.

Except the protruding polyps the surface of Heliopora is very smooth. Maybe the pinnules of the tentacles may be perceived as "hairs".

The biology of Heliopora is similar to the biology of other zooxanthellate Octocorallia except that it has a calcareous skeleton made up from the calcium carbonate mineral aragonite, in contrast to leather and soft corals.

hi , which and how would you classify this species ?
been in possession since 1991, must have sold /traded/gave away a minivan full by now...

 

[Mada]

Here two photos from a different angle of the Heliopora I had. You can see the tiny hair among the other polyps.

Here is what I found in a artikel of Eric Borneman:

- The most often visible structures of Fire corals are the short, thin, hollow, potent stinging tentacles of the mouthless dactylozoids. Dactylozoids, looking like fine transparent hairs, are very important functionally; these nematocyst-laden tentacles provide for both the corals' defense and their primary method of food capture. They are also a primary means of aggressive takeover of territory occupied by other species, along with the overshadowing and crowding out of nearby competitors through rapid growth.-



To me the tiny hairs of the Millepora look visually very similar to those of Heliopora on the photos.
For sure are those of the Heliopora not that stinging but maybe just a little, perhaps to a level that is hard to feel for us (just a thought).
Looking closely to the Heliopora we can see that the tiny hair are coming from big pores.
Maybe is the Heliopora acting like a Millepora to scare predators (just another thought).
I did find some articles/publications including Heliopora facts but none of them describes the tiny hairs and their function/s.
It's intriguing to me.
I keep on searching.

 

[Hans-Werner]

Here two photos from a different angle of the Heliopora I had. You can see the tiny hair among the other polyps.

Very interesting photographs!

I have never noticed something like these hairs on Heliopora. I have looked for something sitting on the coral on your photographs, but it looks like these hairs sit on the places where you can seen the polyp tubes.

hi , which and how would you classify this species ?

This is Heliopora coerulea. You can tell it from the blue skeleton.

 

[Mada]

Very interesting photographs!

I have never noticed something like these hairs on Heliopora. I have looked for something sitting on the coral on your photographs, but it looks like these hairs sit on the places where you can seen the polyp tubes.


This is Heliopora coerulea. You can tell it from the blue skeleton.

I know where to find the new owner of that Heliopora so as soon as I have little time I'll try to make a new photos (hopefully better/sharper ones) and I'll post them.

 

[Hans-Werner]

I know where to find the new owner of that Heliopora so as soon as I have little time I'll try to make a new photos (hopefully better/sharper ones) and I'll post them.

I undertook our Helioporas a closer examination and also found these "hairs" on one specimen.

I found it on one Heliopora sitting on the bottom of a tank that is just 15 cm (6 inches) above the floor. So I had to sit down and bend down to see the little beige or ivory-white spots in the lower part of one Heliopora. With a magnifying glass I saw that the beige spots are tiny tubes and two of the "hairs" coming out of each tube. I am not 100 % sure but I think these tentacles are pinnulate. I think tubes and tentacles belong to tubeworms, maybe Spionidae.

I have no macro lens here at work today but I want to photograph the suspected tubeworms tomorrow or next week.

 

[crusso1993]

hi , which and how would you classify this species ?
been in possession since 1991, must have sold /traded/gave away a minivan full by now...

You do know that I will be hitting you up if and when the time comes!

 

[Mada]

With a magnifying glass I saw that the beige spots are tiny tubes and two of the "hairs" coming out of each tube. I am not 100 % sure but I think these tentacles are pinnulate. I think tubes and tentacles belong to tubeworms, maybe Spionidae.

Wow!
Thus maybe the tiny hairs don't belong to the Heliopora but possibly they are little tubeworms.
Wow, really interesting!
Indeed, if I look closely I see also two of the tiny "hairs".

 

[fishguy242]

Very interesting photographs!

I have never noticed something like these hairs on Heliopora. I have looked for something sitting on the coral on your photographs, but it looks like these hairs sit on the places where you can seen the polyp tubes.


This is Heliopora coerulea. You can tell it from the blue skeleton.

Thank you...
early morning pic, look at that growth ring...

 

[Mada]

I've found another photo of the same coral in the beginning.
At that time I was dealing with a infestation of flat worms (Acoels, waminoa I think) and I treated the corals with Levamisole in a tub for a hour.
Evidently the "worms" with tiny "hairs" have not been bothered bij the treatment.
The acoels were gone.
On this photo we can see clear the tiny "hairs" coming out what look like small tubes with a white border.

 

[Hans-Werner]

Yes, the last photographs shows the tubes of the tubeworms like in our tank. The tubes don't seem to be made of solid calcium carbonate but rather from particles or sediment. They seem to resemble the Polydorella polychaets on the surfaces of sponges.

"Worms" is nearly any kind of invertebrate animal that is much longer than in diameter and has no legs. Acoels are not closely related to polychaets. It doesn't surprise me that medications against flatworms are not active against polychaet worms.