Phyllodiscus semoni
Kwietniewski, 1897
Phyllodiscus
semoni does not look like much during the day. However,
it is a rather bizarre sea anemone that packs an extremely powerful and potentially
dangerous sting. Beegbauer
et al (2009) call the "sting severe, followed by inflammation and long-term
discoloration" and they note it has been reported to have caused a human
death in the Philippines. Mizuno
et al (2007) studying the venom of this anemone states that it targets the
kidney and can cause severe renal injury. Yikes! Don't bump into them. Unfortunately,
they are not easy to recognize. Retracted into a fuzzy mass of
irregular "pseudotentacles," it looks like some sort of variably colored
clump of algae. At
night, alien-like, a disk of more typical anemone polyp tentacles erupts from
the top of the clump, and the stalk stretches upward with the cluster of tentacles
at the top. It is no wonder Dangerous
Marine Animals calls it the "Jack-in-the-box anemone."
The anemones come in various colors, as seen in the photo links below. We have
not seen, or perhaps should say, not recognized many specimens. We have perhaps
eight recorded, but because of their cryptic appearance, they are probably a
lot more common than this low number would indicate. Most were out on the oceanside
reef, but at least two have been seen in the lagoon, one on the reef north of
Bigej and another on the slope of the pinnacle at Victor buoy. Several of these
we were able to see multiple times by returning to the same spots over a period
of a year or so, but all eventually vanished, as though they do not live a very
long time.
Polyp tentacles emerging from the
ball of pseudotentacles.
This one was not recognized when
we were photographing the nearby Tridacna maxima. After noticing it
later while procesing the photo, we had to return to confirm it was indeed an
anemone.
A video frame captue of the anemone
fully expanded.
Updated 4 July 2020
Back to
corals and relatives
Kwajalein
Underwater Home