Family CIONIDAE
Compiler and date details
P. Kott, Queensland Museum, Brisbane, Queensland, Australia
Introduction
The family Cionidae Lahille, 1887, containing a single genus, Ciona Fleming, 1822, is thought to be the most primitive of the extant ascidian families. It is characterised by solitary habit, a horizontal gut loop posterior to the branchial sac, a persistent opening into the posterior end of the pharynx from each of the pair of endodermal epicardial sacs, a large perforated pharynx (branchial sac) with internal longitudinal vessels, and numerous rows of stigmata.
The family Cionidae, once regarded as a member of the Phlebobranchia due to its large flat branchial sac and internal longitudinal vessels, was proposed as a member of the Aplousobranchia by Kott (1969). Cionids lack the renal vesicles (derived from the epicardial sac) that crowd around the gut in Phlebobranchia and Stolidobranchia (Berrill 1950). Further, the epicardial sacs remain entire as in other Aplousobranchia, and their role in the regeneration of lost or damaged tissue is homologous with their role in the replicative process of colonial Aplousobranchia. Cionids also resemble other aplousobranchs in having the gut behind the thorax (rather than alongside), the body being divided into thorax and abdomen.
This family resembles the aplousobranch family Diazonidae most closely, having a similar soft, elastic, translucent test, large branchial sac with internal longitudinal vessels, an oviparous (externally fertilised) habit, and small larvae with few larval or adult organs other than the simple triradially arranged adhesive organs. Cionidae are separated from the Diazonidae by a horizontal (rather than vertical) gut loop. Some Diazonidae form colonies, constituting a further distinction.
Cionidae are represented in Australia by a single species, Ciona intestinalis (Linnaeus, 1767). Records of C. intestinalis are from ports and harbours in all oceans, including all Australia ports, and many estuaries (Kott 1990). However, records from Australian locations later than 1983, are only from St Vincent Gulf (South Australia), Port Phillip Bay (Victoria) and Port Kembla (New South Wales).
Species of the genus Ciona have been reviewed by Hoshino & Nishikawa (1985). Detailed accounts of morphology are given by Roule (1884) and Millar (1953).
General References
Berrill, N.J. 1950. The Tunicata. Ray Society Publications 133: 1-354
Hoshino, Z. & Nishikawa, T. 1985. Taxonomic studies of Ciona intestinalis (L.) and its allies. Publications of the Seto Marine Biological Laboratory 30(1–3): 61-79
Kott, P. 1969. Antarctic Ascidiacea. A monographic account of the known species based on specimens collected under U.S. Government auspices 1947 to 1963. Antarctic Research Series 13: i-xv 1-239
Kott, P. 1990. The Australian Ascidiacea Pt 2, Aplousobranchia (1). Memoirs of the Queensland Museum 29(1): 1-266
Lahille, F. 1886. Sur la classification des Tuniciers. Comptes Rendus (Hebdomadaires) des Séances de l'Academie des Sciences. Série D. Sciences Naturelles 102: 1573-1575
Millar, R.H. 1953. Ciona. L.M.B.C. Memoirs on Typical British Marine Plants and Animals 35: 1-123
Roule, L. 1884. Recherches sur les ascidies simples des côtes de Provence 1. Phallusiadées. Annales du Musée d'Histoire Naturelle de Marseille, Zoologie 2(1): 1-270
History of changes
Published | As part of group | Action Date | Action Type | Compiler(s) |
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14-Dec-2012 | 14-Dec-2012 | MODIFIED | ||
12-Feb-2010 | (import) |