Calvadosia cruxmelitensis
Stauromedusae UK - An online guide to the Stalked jellyfish (Stauromedusae)
found around the coastal waters of the United Kingdom and Ireland.
Includes notes on their identification, and where and how to find them.
- St. John's stalked jellyfish*
N.B. Recent name change from Lucernariopsis cruxmelitensis Corbin, 1978 ref. Systematics of stalked jellyfishes (Cnidaria: Staurozoa) Lucılia S. Miranda, Yayoi M. Hirano, Claudia E. Mills, Audrey Falconer, David Fenwick, Antonio C. Marques and Allen G. Collins. 2016.
WoRMS taxon details for -
Calvadosia cruxmelitensis Corbin, 1978 - External Link
Oral view of Calvadosia cruxmelitensis
Lateral view of Calvadosia cruxmelitensis
* Calvadosia cruxmelitensis was in 2010 given the name ‘’St. John's stalked jellyfish’’ in a national newspaper competition run in conjunction by the Guardian newspaper and Natural England.
Brief Description
- Calyx, widely funnel-shaped, usually maroon in colour.
- Bell to 18mm diameter, bell and stalk (peduncle) height similar, up to 8mm for each.
- Base of bell involuted around stalk (peduncle).
- Arms equidistant, but their length can vary from specimen to specimen.
- Broad basal disk (pedal disk).
- Up to 35 tentacles in tentacle cluster at tip of arm.
- Nematocysts form the shape of a Maltese Cross, this may be pronounced in some specimens and less so in others.
- Olive-yellow manubrium (mouth)
Calvadosia cruxmelitensis was first described by P.G. Corbin, in 1978. ref: A new species of the stauromedusan genus Lucernariopsis (Coelenterata: Scyphomedusae). Journal of the Marine Biological Association of the United Kingdom. 58(02), 285-290. (External link to Cambridge Journals - Purchase neccessary).
This species is one of the prettiest and most colorfully marked species we have in the UK and is one of significant local importance to the author of this website because of its frequency around Penzance, Cornwall; the species being frequently found across Mounts Bay.
It is instantly recognised in the field from other stalked jellyfish by its short stalk and uniform rows of white nematocysts either side of the arms which give the overall appearance of a cross. This feature gives the animals its common name, the St. John's stalked jellyfish, this arrangement was originally described by Corbin as being in the shape of a Maltese Cross. The body and tentacles of the species are usually maroon or dark maroon in colour, two rows of white nematocysts run parallel down the arms and in the centre is found an olive-yellow manubrium, this is usual colour, but pinkish and olive-khaki shades were noted, by Corbin. Pink shades were recorded at Albert Pier Reef in Penzance, Cornwall, 2011; also an unusual pale pink specimen was observed at Marazion 19.03.14.
The species differs from Calvadosia campanulata in that the nematocysts of Calvadosia campanulata are more scattered and appear more randomly over the entire body of the animal. Calvadosia campanulata is also more likely to vary in colour and two distinct spots may be present on the side of the bell, these may be pale blue or white.
P.G. Corbin, who first described Calvadosia cruxmelitensis stated that the species is "most frequently on Chondrus / Gigartina, quite frequently on Ulva / Enteromorpha, Gracilaria, Furcellaria, Polyides, Corallina, Ceramium and other similar feathery algae, but infrequently on Codium, Cystoseira and Calliblepharis."
Ref: A NEW SPECIES OF THE GENUS LUCERNARIOPSIS (COLENTERATA: SCYPHOMEDUSAE) by P.G. Corbin. Journal of the Marine Biological Association U.K. (1978) 58, 285-290.
In Mounts Bay the species is also regularly found on Eelgrass (Zostera marina). The most favoured algal species in the bay being Chondrus, Corallina and Calliblepharis on or near reefs; and also on Gracilaria where reefs occur close to sandy areas.
Comparison shot with Calvadosia campanulata
SPECIES PAGES FOR 2007 UK BAP PRIORITY SPECIES
PDF File - By kind permission of the JNCC.
Joint Nature Conservation Committee.
Selection of images
Selection of larger images (1200 x 900), chosen to best display the species. Images taken at various locations in Cornwall in August / September 2012. All images ©David Fenwick.
The habitat images above were taken by Carol Tucker, on days when Calvadosia cruxmelitensis was recorded at the site. Marazion Causeway is within the proposed Mounts Bay Marine Conservation Zone boundary.
Macro images of Calvadosia cruxmelitensis
(Click on image link to view larger 1200 x 800 images)
Calvadosia cruxmelitensis oral surface of bell close-up
Calvadosia cruxmelitensis gonadal sacs close-up
Calvadosia cruxmelitensis manubrium (mouth) closed
Calvadosia cruxmelitensis manubrium (mouth) open -1
Calvadosia cruxmelitensis manubrium (mouth) open -2
Calvadosia cruxmelitensis secondary tentacles -1
Calvadosia cruxmelitensis secondary tentacles -2
L. cruxmelitensis arm with nematocysts in parallel rows
Calvadosia cruxmelitensis juvenile oral surface -1
Calvadosia cruxmelitensis twin-headed variant
found at Marazion, Penzance, Cornwall. 16.04.14.
An 8mm oral diameter, female specimen, producing eggs on collection. Click on image link to view larger images.
Calvadosia cruxmelitensis - twin-headed variant 1
Calvadosia cruxmelitensis - twin-headed with eggs 1
L. cruxmelitensis - orally measured with 0.1mm rule 1
L. cruxmelitensis - laterally measured with 0.1mm rule 1
Calvadosia cruxmelitensis - eggs on slide 1
Calvadosia cruxmelitensis - eggs on slide 2
Calvadosia cruxmelitensis - eggs on slide 3
Calvadosia cruxmelitensis - eggs on black perspex 1
Eggs were produced after placing the specimen in a collecting tube. The eggs may have been produced after and on replacing the water in the tube with cooler water, and after the water in the tube had become warm. Temperature may therefore have an affect on spawning; and thus may occur in warm, shallow, lowershore pools, as colder water enters the pools on an incoming tide. This needs to be scientifically proven.
Macro images above taken using a Canon 5D MkII DSLR camera, MP-E 65mm lens, MT-24EX Twin Flash, and sometimes, a full set of Kenko extension tubes and 1.4x Kenko TelePlus Pro 300 teleconverter. Camera setup.
Calvadosia cruxmelitensis with algae-bacterial mat
possibly made up of naviculoid diatoms
(Click on image link to view larger images)
Calvadosia cruxmelitensis oral view
Calvadosia cruxmelitensis aboral view with mat
Algae-bacterial mat of naviculoid diatoms ? -1
Algae-bacterial mat of naviculoid diatoms ? -2
Records
DEVON
Records by P. G. Corbin before species was described.
Wembury, Church Reef, an undescribed species, occasional, on algae, low tide; moderate numbers (2
-3 dozen) in one restricted area, Aug. Feb. 1955; elsewhere on Reef only 2 or 3 specimens, 1951-5. 3 specimens at half-tide in pools, 26.1.55.
Wembury, W. Reef, occasional in one restricted area, 1951-5.
CORNWALL
Records by P. G. Corbin before species was described.
W. Looe, 1 specimen only, 1951-5, in pool at half-tide, 12.5.52.
Other Cornish records
In Mounts Bay, Cornwall, at Long Rock, Calvadosia cruxmelitensis is frequently encountered on Eelgrass (Zostera marina), on extremely low spring tides. Some texts describe the species as being rarely found on Eelgrass. At Albert Pier Reef, beside Penzance Harbour, the species is commonly found on Carragheen or Irish moss (Chrondus crispus), on old stipes of Japweed (Sargassum muticum), and on Coral weed (Corallina officinalis) in narrowing pools and runnels on the middleshore. The best month to see this species is probably during December, but the species is frequently recorded in Mounts Bay between November and March, and at the following locations, St. Michael’s Mount Causeway, Battery Rocks, Chimney Rocks and Lariggan Rocks. The sites mentioned occur within a 5km length of coastline. Calvadosia cruxmelitensis has also been recorded locally from Trenow Cove and King’s Cove by Prussia Cove, Cornwall, by Stella Turk, in the late 1970s. Elsewhere in Cornwall, records are few and widespread.
Calvadosia cruxmelitensis may also be found on the red algae Gigartina. Ref. Handbook of the Marine Fauna of North-West Europe. Edited by P. J. Hayward and J. S. Ryland.
Records of Lucernariopsis cruxmelitensis held on
the Cornish ERICA database to January 2014
Distribution Maps and Links
Maps and links here should only be used as a VERY rough guide. A square in any map may represent one record or hundreds or records. A square can also only be added if there is data to support its placement and it appears there are issues with the sharing of data between local and national databases. Only a certain number of sightings will ever get reported to recording schemes and that in general data will largely be provided from areas closer to human habitation as that's where most recorders live.
General Distribution -
W. and SW. coasts of Eire.
NW. coast of Northern Ireland at Malin Head.
N. Cornwall.
N. Devon coast westwards from Woody Bay near Lynton.
English Channel from Land's End to Swanage.
Channel Islands.
Ref: A NEW SPECIES OF THE GENUS LUCERNARIOPSIS (COLENTERATA: SCYPHOMEDUSAE) by P.G. Corbin. Journal of the Marine Biological Association U.K. (1978) 58, 285-290.
Distribution of Calvadosia cruxmelitensis
in Cornwall from ERICA database (2km)
UK Distribution Map (10km) from NBN Gateway
Please note -- This map above appears to lack data.
Link to Calvadosia cruxmelitensis on NBN Gateway
Stauromedusae UK - Photographic Guide
- Calvadosia cruxmelitensis images
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Weblinks
MarLIN species pages for Calvadosia cruxmelitensis
Natural England Marine Conservation Zone priority species
information for Calvadosia cruxmelitensis
The following works were used in compiling and checking information for the Brief Description found on this page -
Journal of the Marine Biological Association of the United Kingdom / Volume 40 / Issue 01 / November 1961, pp 292-303.
"Handbook of the Marine Fauna of North-West Europe". Edited by P.J. Hayward and J.S. Ryland.
