Stalked Jellyfish Depastrum cyathiforme
Haeckel's plate XXI, 1879, as Depastrella carduella
Stalked jellyfish belong to the order stauromedusae, not true jellyfishes in the pelagic sense, many are found in shallow waters, and may be found intertidally attached to algae or seagrass. There are ten species of stauromedusae in the UK, Depastrum cyathiforme is the only species that may be found attached to rock or stones on the shore. It prefers the sides or undersides of rocks in pools, but it may be found as part of under-boulder communities, attached to overhangs or sides of ledges covered by algae such as Saw wrack, and may also be found amongst some sea squirts in these locations. Where found out of pools, it is presumed it may be found on the north sides of boulders or ledges in weed sheltered locations to avoid desiccation by the sun or wind. The species has been reported as more frequent on the middle shore, but with larger specimens less frequently occurring lower down the shore in the Laminaria zone.
Depastrum cyathiforme was first found in the United Kingdom at Southend Harbour, Arran, on the 2nd. June 1846, by David Landsborough Jnr. during an excursion with his father the Reverend David Landsborough; the species was rather importantly described at the time as being abundant. The species was drawn and later identified by Mr. Joshua Alder on the 14th April 1847, on receiving the first part of Sars's 'Fauna littoralis Norvegiae', the species was first described as Lucernaria cyathiformis. It is presently unclear where the discovery was made, but Arran naturalist Colin Cowley is currently looking into this and is looking for suitable sites on the south coast near to Southend Harbour where the first find was reported. The species was also reported from the shore at Corriegills.
The species is described as being urn or goblet-shaped, but I'd like to describe the overall appearance as quite thistle-like in lateral view. Specimens have been described as being approximately 6-10mm wide and 12(-14)mm in high, but specimens found may be much smaller. Unlike other UK stauromedusae it does not have arms, and tentacles are found around its oral disc. The species has been described as grey-brown in colour with ripe gonads whitish to pinkisk.
The species is historically reasonably well documented in Scotland and there are more documents concerning the species in Scotland, than anywhere else in the UK. Professor Allman described the species as being found by a Mr. Gilchrist at Stromness, Orkney Islands in August 1859. E.S. Russell describes the species as being found near Lion Rock, Millport, Greater Cumbrae, and near the old castle, on the east side of Little Cumbrae, in July 1903. Richard Elmhirst, F.L.S., Superintendent of the Millport Marine Biological Station, describes the species as being found close to Millport Marine Biological Station in 1909, presumably near Lion Rock.
Recent evidence for the occurrence of this species in the UK is much harder to find, with the most recent record occurring on Lundy Island, off the Devon coast in 1951. The recurring theme is that the species prefers island sites.
The reason I write, is out of concern, for this species, for it has not yet been found at any of its historic locations. Depastrum cyathiforme appears during the summer, it fixes to rock and stone, and so is well within the reach or discovery by recorders, and therefore should be more frequently recorded, but it isn't. There is of course no better place to try and find it than where it has been historically recorded, and where better to look than where it was first recorded in the UK, than on the Isle of Arran.
Because of the lack of records we currently have no good digital images of the species or the habitat it frequents. Images are needed so marine recorders and others can best recognise the species at sites around the UK, and so the species can be best promoted using the internet and social media. Specimens are also required for scientific research and DNA analysis. We are quite fortunate in that Dr. Allen Collins of the Smithsonian Natural History Museum, Washington, USA is currently conducting a revision of the stauromedusae, so finding the species on Arran will not only confirm an old record, but it'll further help in promoting the species nationally and advance our scientific understanding of the species.
More information on the species can be found on a website I have dedicated to UK stauromedusae, which can be found at www.stauromedusae.co.uk
E-mail: davidfenwicksnr (at) googlemail.com replace (at) with @ this is to prevent spam.