Phylum: Chordata (Chor-da-ta) animals with backbones
Class: Ascidiacea (Ascid-ia-ce-a) ascidians, tunicates, sea squirts
Neville Coleman has been finding, photographing ascidians/sea squirts underwater, collecting and identifying sea squirts/ascidians for over 40 years.
There are at least 2000 types of ascidians in the world’s ocean. They are entirely marine and live at all depths from intertidal down to the abyssal trenches.
They can be found on reefs, rubble, algae, seagrasses, shells, rocks, in caves, under ledges and in sand and mud.
Red - brested Ecteinascidia
Ecteinascidia maxima Kott, 1985
Originally discovered and photographed at 15 metres at Sugarloaf Island,
Lord Howe Island in 12/1979 this superb species is easy to recognise to species even though the red colouration more distinguished in some colonies. (Queensland Museum)
They live as solitary or colonial animals attached to the substrate for their entire adult life. A colony grows as the small individuals in it replicate (by budding or subdivision).
Solitary ascidians just increase in size and shed their outer skin (tunic) on a regular basis.
Sea squirts, or ascidians, may not be the most well known underwater creatures yet they are the most advanced of invertebrates. Their singular unique character is a perforated pharynx, a sieve that traps their food as they pump water in through the mouth. Their other body opening is an aperture ejecting spent water waste products, eggs, sperm or larvae. The larvae are tadpole-like and have a notochord, or rudimentary backbone.
Sea squirts (including tunicates) are enclosed in an external coat (or tunic) of a cellulose-like substance (called tunicin) unique in the animal kingdom. Solitary animals are usually large, with a sac-like body with their gut and gonads tucked up beside the large perforated pharynx and the mouth opening is larger than the exhalant opening.
Many species live communally, either as singular tests attached to each other by a common base (colonial ascidians) or as a colony of separate zooids formed into a firm jelly-like matrix or investing sheet of tunicin (compound ascidians).
Many compound ascidians have exquisite patterns and colours with pigment particles or blood vessels scattered throughout. The small or intake siphons are often formed around a larger communal exhalant siphon (looking like minute rosettes).
Although some compound ascidians are superficially similar (visually) to sponges they are easily distinguished from one another.
Ascidian siphons close at any disturbance. Sponges (having no nervous system) show no obvious reaction to disturbance and their oscula openings remain open.
Visual recognition to species level has come a long way over the past 30 years and many ascidians can now be recognised from a good photograph. However, specific identification often depends on dissection of taxonomically preserved specimens and specialised knowledge.
Clivose Aplidium
Aplidium clivosum Kott,1992
Original speciemen was photographed and collected at 3m off Kangaroo Island, South Australia 12/03/78. It is now known to range from northern Queensland to north Western Australia and inhabits depths from 2 to 30 metres. Colour can be orange, brown, pink, orange or, buff.
(Queensland Museum)
Latticed Aplidium
Aplidium crateriferum Kott,1992
A very visually distinctive species, this ascidian occurs in depths from 8 to 30 metres and may be seen as roundish colonies. This one was found and photographed at Heron island, Great Barrier Reef on 26/11/1974. Colour is generally as shown, but can also be white whitish, or grey.
(Queensland Museum)
Freckled Aplidium
Aplidium lenticulum Kott, 1992
Original specimen was found and photographed in a cave at 7 metres off
Rottnest Island, south Western Australia on 23/1/1972.
As can be seen in the image below there is only a small range in colour and this could be put down to the differences in strobe lighting from bulbs on this image, to electronic strobes on the lower example some 35 later. (Queensland Museum)
Freckled Aplidium
Aplidium lenticulum Kott, 1992
Although not every ascidian can be visully identified in situ, with enough original material, information and images the majority are possible. This species is quite distinctive with a characteristic patern and little variation in colour. This colony ( 200 mm across) was discovered at 20 metres off Albany, south Western Australia.
Multifolded Aplidium
Aplidium multiplicatum Kott, 1992
Original specimen and image from 10 metres at Wistari Reef , Heron Ilsad, Great Barrier Reef on 18/07/1975. Most colonies observed were orang in colour with white opaque inhalent siphons.
(Queensland Museum)
Tabascum Aplidium
Aplidium tabascum Kott, 1992
Well patterned and easily determined, this species needs to be studied in close up to see its most characteristic identification features. It came from 20 metres off Heron Island on 16/07/1973.
( Queensland Museum)
Tabascum Aplidium
Aplidium tabascum Kott, 1992
Over 600 mm across the colony, this investing species is faily stable in colour and is found on the sides of bommies and on reef slopes from 8 to 30 metres.
( Queensland Museum)
Marion Reef Atriolum
Atriolum marinense Kott, 2001
The globe - shaped colonies of this species are only fairly small, with the largest being only 20 mm across. It was located at 20 metres at Marion Reef in the Coral Sea on 24/08/1977. (Queensland Museum)
Black Clavelina
Clavelina nigra Kott, 1990
Translucent black in colour with distinctive white ringed siohons, these small colonies appeared to be no more than 80 mm across. Found and photographed at 18 metres off Rottnest Island, south Western Australia on 12/03/1972.
( Queensland Museum)
Corkscrew Ascidian
As yet this fantastic exmple of nature's munificence remains a mystery.
it was discovered at 15 metres in Milne Bay, Papua New Guinea in November 2004. Specimen was all of 12 mm across.
Red - breasted Ecteinascidia
Ecteinascidia maxima Kott, 1985
Found living in sandy gutters on rock walls, bommies these beautiful, very characteristic colonial species is found at Lord Howe island and also at Split Solitary island of Coff's Harbour, New South Wales.
Loloata Ecteinascidia
Ecteinascidia sp.
Fisrst photographed during a fauna survey at Loloata island, Papua New Guinea in 11/1989 this species was found growing on the bottom of a wreck in Bootless Bay. The species grows in colonies arund 50 mm across and is not commonly encountered. It has also been recorded from Milne Bay, Papua New Guinea over more recent years.
Neville at work
Most of my diving career I have had to carry 3 camera systems to be able to shoot enough images to try and establish records of the ocean's inhabitants with the maximum number of dives at any one location on any one day. This, together with the time involved to collect each specimen I photographed, meant completing lots of dives in all kinds of conditions, day and night.
Somebody once commented that I looked like a Christmas Tree each time I went diving; there was no doubt, I certainly felt like one, that's for shore, BUT the results speak for themselves. There was no other way to do the job properly!
Brown Lissoclinum
Lissoclinum badium Monniot & Monniot, 1996
Located and photographed at 15 metres at Heron Island on the Great Barrier Reef during 10/1977 this investing species may cover up to 1 metre in a single colony. It can be brown, or grey - green in colour and always has yellow, or orange around the exhalent siphons.
( Queensland Museum)
Spongy Lissoclinum
Lissoclinum spongium Kott, 2001
Living on reef from 20 to 40 metres, these bright green colonies were discovered at 20 metres off Roach island, Lord Howe Island on a research fauna survey during 10/1987. The species can be seen in wide spreading colonies up to 2 metres in diameter.
( Queensland Museum)
Magic Ascidian
Clavelinidae
Only 15 mm across the entire colony, these colonial asciians were first photographed at 12 metres at Tulamben, Bali 11/1997. As yet we have not been able to etablish their identity.
Modified Perophora
Perophora modificata Kott, 1985
One of the original Milne Bay, Papua New Guinea discoveries made on some of the first dive expeditions in the region ( 04/1982) this species always appears to be yellow, or white in colour and the colonies up to 60 mm across.
( Queensland Museum)
Oriental Polycitorella
Polycitorella orientalis Kott, 1990
At all of 25 mm, this colony is certainly not a large one, yet good enough to establish a new species. Originally found and photographed at 8 metres at Swain Reefs, Great Barrier Reef in 09/1974. The species was rare at this location and over the years, I have never found another.
( Queensland Museum)
Inflated Pseudodistoma
Pseudodistoma inflatum Kott, 1992
Found and photographed during the original fauna survey to establish a marine park at Julian Rocks, Byron Bay, New South Wales ( 03/75) this species was quite common at depths of 20 metres and has also been found at Cook Island and the Gold Coast.
( Queensland Museum)
Slender Pseudodistoma
Pseudodistoma gracile Kott, 1990
Found and photographed in only 3 metres of water at Kangaroo Island, South Australia in 03/1978. The original colony here was only small(60 mm) but can grow to a colony size of 500 mm. It is now known to extend into Victorian, Tasmanian, New South Wales and Queensland waters.
( Queensland Museum)
Southern Pseudodistoma
Pseudodistomida australe Kott, 1990
Photographed and collected from 8 metres of water at the Murion Islands, Exmouth, Western Australia during 08/1972 this very attractive ascidian grows in clumps of lobes that are attached to a common base.
( Queensland Museum)
Castle Synoicum
Synoicum castellatum Kott, 1992
First encountered at the Keppel Islands, Queensland at 10 metres on reef in 07/1978. The pattern if fairly unique and can be visually identified by comparison with a good image. It is also found on the Great Barrier Reef.
( Queensland Museum)
Baggy Synoicum
Synoicum sacculum Kott, 1992
An excellent shallow water dive, Flinder's Jetty, Victoria has produced quite a number of new species through the years. This species was found at 5 metres during the 06/1977 fauna survey.
( Queensland Museum)
Baggy Synoicum
Synoicum sacculum Kott, 1992
Found down to 425 metres ( from dredging/trawling samples) the species usually shows the presence of a sandy coating, or streaks of sand over the lobed colony. Colonies are 50 to 70 mm across.
( Queensland Museum)
Horny Synoicum
Synoicum buccinum Kott, 1982
First found at Marion Reef, Coral Sea in 20 metres of water during 08/1977 the spread of the colony clumps is around 50mm. It is also found at Heron Island and Wistari Reef on the Great Barrier Reef. Yellow appears to be the main colour form.
( Queensland Museum)
Beautiful Stomozoa
Stomozoa bellissima Kott, 1990
Found during August of 1972 at Exmouth Western Australia in only 5 metres of water this strange little ascidian was only encountered once during my around Australia expedition.
( Queensland Museum)
Indian Ocean Symplegma
Symplegma sp.
Photographed at 8 metres in mahe, Seychelles, this species is yet to be identified as it does not resemble any known form. It is also present in the Maldives.
Honeycomb Ascidian
This unusual and undescribed species was first photographed at 25 metres off Terrigal. New South Wales during 07/1983. It was deemed to be a new species and was not found again by myself for another 17 years.
Honeycomb Ascidian
Found for only the second time (again at 25 metres) in Sydney Harbour, it is now verified that this species is amongst the deeper water fauna of the central/southern coast of New South Wales.
MORE SPECIES BEING ADDED AT REGULAR INTERVALS