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Cushion Star, Porania pulvillus, and the Sunstar,Crossaster papposus

Echinodermata

Greek   echinos = sea urchin,  derma = skin.

Marine animals that are radially symmetrical (most species) and contain a unique water vascular system, and tube feet that are used for movement, respiration, protection (spines) and assist in the capture of food.

Cushion Star, Asterina gibbosa, with the Shore Urchin, Psammechinus miliaris.



    Photograph by Robert Jones (Trowbridge)

The Cushion Star is only found on the shore and in the seas to the south and west of the British Isles. The Purple-tipped Shore Urchin has a more widespread distribution but is not particularly common between the tides, although it seem to be known from most rocky coasts where it is usually found attached to the underside of rocks near the low spring tide mark.

Echinoderm Links
http://www.calacademy.org/research/izg/echinoderm/echilink.htm
The Echinoderm Newsletter
http://www.nmnh.si.edu/gopher-menus/TheEchinodermNewsletter.html
Echinoderm Page (External)
http://www.isl.net/~helf/echino/
Photographs from Loch Fyne
http://www.diworkshop.ndirect.co.uk/Lfyne.htm

A small specimen of the Sunstar, Crossaster papposus.

Echinocardium cordatum

Reports of Asterias rubens (Link)
 

26 March 2008
After a recent bout of northerlies in North Wales I took the dog for a walk down on Red Wharf Bay on Anglesey and found all sorts of things washed up. Much of the material was deposited across the entire intertidal to the east of the bay, but more concentrated on the strandline towards the west. 
Brittlestars (various species) were particularly abundant on the upper shore, with patches a couple of inches (or more) thick. Common Starfish, Asterias rubens,  were also very abundant, as a rough guess at 5-10 per square metre with species such as the Sand Starfish Astropecten irregularis, and Heart Urchin Echinocardium cordatum. 

Over Easter, after some heavy storms with snow blowing in off the North Sea, I discovered hundreds of Common Starfish, Asteria rubens, a lot of Sunstars, Crossaster papposus, and Brittlestars washed up on the sands of Holkham Beach, Norfolk.

Hundreds of the sea cucumber Thyone fusus, many exuding their guts and gonads as a response to the stress, were discovered washed dead on up on the shore Newborough in North Wales (only a few nautical miles from Dinas Dinlle). 

12 March 2008

December 2006
Two deep watersea stars were recorded and collected by a ROV submersible, the first a beige species with short arms (like a cushion star) from a depth of around 250 metres off west Norway, and the second similiar one from a depth of 600 metres in a Norwegian fjord at an earlier date. Neither of these species have been positively identified at time of writing.
Full Report with the Links to Images

The species are suggested as Peltaster placenta and Diplopteraster multipes.
 

28 January 2006
Thousands of dead specimens of the Common Starfish, Asteria rubens, were washed up on the beach about a mile and a half to the north of Tywyn on the Cardigan Bay coast of north-west Wales.  There seem to be various interpretations of these mass strandings, including winter storms and changes in water temperature.

13 January 2005
Hundreds of Sea Cucumbers were amongst the wreck of animal remains discovered on the Dinas Dinlle beach west of Llanwrog (south-west of Caernarfon), north-west Wales. 
 

They were scattered all over the strandline and shore with other remains including the common Mermaid's Purses (egg cases of the Dogfish) and the decaying carcass of a dead Seal. Sea Cucumbers are an unusual echinoderm washed up between the tides. 

The sea cucumber looks like Thyone fusus can be found as far north as Norway grows up to 20 cm.

Sea Cucumbers; General Information - 1
Sea Cucumbers; General Information - 2

c. 11 June 2003
On the beach from Sutton-on-Sea up to Mablethorpe, East Lindsey (Easy Yorkshire), we noticed thousands of dead starfish ranging from 3-10 cm in size, along with large numbers of dead crabs and some small shellfish. The starfish were almost certainly the Common Starfish, Asterias rubens.

27 September 2002
The pink starfish with 13 legs discovered on Bridlington beach, Yorkshire, was the Sunstar, Crossaster papposus. This is a common species but it is not often reported washed up on the shore.

17 March 2002
Thousands of Common Starfish, Asteria rubens, are washed up on the beach at Holkham, Norfolk, on the east coast of England after sustained north-easterly gales.

c. 14 March 2002
After a sustained period of north-easterly gales, there was a massive stranding of marine animals and weed on the Yorkshire shore (north-east England) between Fraisethorpe and Barmston (East Yorks: Holderness). The most noticable of the animals washed up were hundreds of thousands of starfish mostly of the Common Starfish, Asteria rubens, but other species were present. The list of interesting animals washed up included decapod crustaceans including Lobsters that were still alive, crabs etc., a wide variety of fish, sea anemones, polychaete worms, molluscs including octopuses, porpoises, seals and tonnes of seaweed. This is the largest stranding recording on these web pages.

28 August 1999
A commercial fishermen found the beautiful orange starfish, Echinaster sepositus, north of Herm Island. The crab potter has fished for 20 years and had never seen one before. The books say that this starfish reaches the northern part of its range in the Channel Islands.

Northern Cushion Star

Porania pulvillus



This colourful cushion star is is an exceptional find on the shore and is not often reported by divers, preferring deep cold seas.

Cushion Star

Asterina gibbosa



Cushion Star on Constantine Bay beach, north Cornwall
Photograph by Amanda Bertuchi

This small cushion star inhabits the shore on south and western rocky coasts of Britain only.
Asterina spp. on S W Wales shores (Link)

I can add that this starfish is most plentyful here along the Norwegian coast. Not uncommon to see 10 or more in a dive. Usually most abundant in winter months. Some have commensals.

Glossary of Echinoderm terms:
 

Pedicellariae: tiny modified spines topped with 2- or 3-jawed pincers, very mobile and sometimes poisonous, which are used to remove settling larvae and other material from sea urchins (or starfish).

Papulae:   little fleshy projections of the body wall in starfish, which give an increased surface area for gas exchange and excretion; large numbers give it a slightly 'furry' look.

Ambulacrum: one of five bands of small plates running from the top to the bottom of a sea urchin, through which the tube feet emerge. The ambulacra are separated by wider inter-ambulacra made up of larger plates. The other echinoderms (starfish; brittlestars; sea cucumbers and feather stars) also have tube feet emerging through ambulacra, but the details are different.