(Milne-Edwards, 1841)

Description

External appearance
Colonial, with zooids immersed. Colonies forming soft, gelatinous, thin sheets (less then 2 mm thick). Test transparent, sometimes with brown or grey pigmented cells, without calcareous spicules.

Characters
Zooids up to 2 mm in length; body divided into thorax and abdomen. Oral siphon 6-lobed; atrial opening large, exposing much of the branchial sac. Up to 24 thin branchial tentacles of variable size. Branchial sac bearing 4 rows of straight stigmata; without longitudinal bars or folds. Retractor muscle well-developed, extending from the posterior end of the thorax. Gut abdominal; stomach smooth. Gonads left of gut; testis bilobed; sperm duct not coiled; ovary beside testis (D. listerianum zooid).

Habitat
Attached to hard substrata; from low water level to depth of about 80 metres.

Distribution
Almost cosmopolitan.

Kingdom Animalia
Phylum Chordata
Subphylum Tunicata
Class Ascidiacea
Order Enterogona
Suborder Aplousobranchia
Family Didemnidae
Genus Diplosoma
Species listerianum

Status in World Register of Marine Species

Accepted name: Diplosoma listerianum (Milne-Edwards, 1841)

Scientific synonyms and common names

Leptoclinum listerianum Milne-Edwards, 1841
Diplosoma spongiforme Giard, 1872
Leptoclinum gelatinosum Alder & Hancock, 1912
Leptoclinum punctatum Alder & Hancock, 1912

Alder, J. & A. Hancock 1912. The British Tunicata: an unfinished monograph, volume III, edited by J. Hopkinson. Ray Society, London.

Berril, N.J. 1950. The Tunicata, with an account of the British species. Ray Society, London. 354 pp.

Knight-Jones, E.W. & J.S. Ryland 1990. Hemichordata and Urochordata. In: P.J. Hayward & J.S. Ryland (eds), The Marine Fauna of the British Isles and North-West Europe, vol. 2 Molluscs to chordates, Clarendon Press, Oxford: 872-904.

Millar, R.H. 1966. Tunicata Ascidiacea. Marine invertebrates of Scandinavia, 1: 1-123.

Millar, R.H. 1970. British Ascidians. Synopses of the British Fauna, N.S 1, 1-92.

Berril, N.J., 1950. The Tunicata, with an account of the British species. Ray Society, London. 354 pp.

No distribution map was available at OBIS the last time we checked. Retry now.

You can continue searching for Diplosoma listerianum on one of these Web sites:

Fauna Europaea (animals) | IOPI (plants) | NCBI (genetic)

Google | Yahoo | MSN | Wikipedia