What is This?
WHAT IS THIS?
PHOTO of a Benthic Ctenophore
A benthic ctenophore,Coeloplana sp?. Note partially everted set of tentacles. Off East Point, 6m, Darwin, Northern Territory, Australia. June 1987. PHOTO: Bill Rudman.
Ctenophores, commonly called Comb Jellies or Sea Gooseberries, were previously considered to be Cnidarians, because like jelly fish and sea anemones, ctenophores also have nematocysts. Today they are considered to represent a separate Phylum, the Ctenophora. Most are pelagic animals, spherical in shape, which swim by bands of large beating cilia, arranged in vertical rows, each band being likened to comb, hence the name “Comb Jelly”. The ‘jelly’ is a reference to Jelly Fish. Ctenophores catch their prey by everting two groups of stinging and sticky tentacles.
There are however a small group of ctenophores [Platyctenida] which have evolved into benthic ‘slugs’. At first glance they are usually considered to be flatworms, but if you look at them carefully you will find a pair of pores or swellings which indicate the chambers in which are stored the stinging tentacles. Quite often found on soft corals, like acoel flatworms, there are only a few described species, but probably many yet to be recognised. Most are less than 10-15mm long.
Rudman, W.B., 1999 (November 25)
Benthic ctenophores from Bali
October 27, 2008
Picture by: Supapong Areeprasertkul
Supapong, A., 2008 (Oct 27) Benthic ctenophores from Bali. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20530
These are not slugs, but because they look like they could be, I have a page for them on the Forum. They are benthicCtenophores. These animals, also called ‘Comb Jellies’ or ‘Comb Jellyfish’ are usually pelagic animals found swimming or drifting in the plankton. They have a pair of long branched tentacles for entangling their prey which can be retracted into sacs in their body. Your animal is one of a small group which live sedentary non-swimming lives attached to the sea floor or objects. The two ‘ear-like’ structures in your animal are the sacs into which the tentacles retract. …
Photo from: oceanexplorer.noaa.okeanos