Family LEUCASCIDAE Dendy, 1893

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Introduction

Leucascidae Dendy, 1893 occur in massive, lobate and pear-shaped growth forms with single or many oscula. The ectosomal cortex is characteristically well developed. Triradiate (Hooper & Wiedenmayer 1994: fig. 147) and quadriradiate spicules (Hooper & Wiedenmayer 1994: fig. 158) of the chamber layer are irregularly scattered in the walls of the elongate chambers where they occur in a two-dimensional arrangement associated with exhalant canals. Choanocyte chambers are long, tubular and branched, arranged radially around the exhalant canal system (Hartman 1982).

Borojevic et al. (1990) provide another diagnosis of the family, emphasising body form; they suggest that these sponges have a body differentiated into a cortex and a choanosome whose organisation is reminiscent of a clathroid body composed of anastomosed tubes; choanocyte chambers are tubular, often highly ramified and anastomosed; and choanosome skeleton is restricted to the walls of the choanocyte chambers, maintaining a distinct tubular organisation. Borojevic et al. (2002) cite an incorrect reference for the date of establishment for the family, as 1892 instead of 1893 - the latter subsequently reconfirmed.

Three genera are included in this family, scattered in the tropical and warm-temperate seas (Indian Ocean, Mediterranean, Channel coast of France). Both genera are known to occur in Australian waters. They are found down to depths of at least 150 m (Hartman 1982).

Reviews are available in Dendy (1893); Bidder (1898); Dendy & Row (1913; Leucetta and Pericharax added); Burton (1963; discussion, dropped); Hartman (1958; retained in Leucettida); Borojevic (1968; in Calcinea, differentiation from Leucettidae, phylogeny; Leucascus and 'Ascaltis' (sensu novo, =Aulorrhiza) included); and Hartman (1982).

Diagnosis

Clathrinida with a body differentiated into a cortex and a choanosome whose organisation is reminiscent of a clathroid cormus composed of anastomosed tubes. The cortex contains a specific skeleton, composed of large triactines and/or tetractines. Choanocyte chambers are tubular, often highly ramified and anastomosed. The choanoskeleton is restricted to the walls of the choanocyte chambers, maintaining a distinctly tubular organisation.

ID Keys

See order Clathrinida diagnosis

Diagnosis References

Borojevic, R., Boury-Esnault, N., Manuel, M. & Vacelet, J. 2002. Order Clathrinida Hartman, 1958. pp. 1141-1152 in Hooper, J.N.A. & Soest, R.W.M. Van (eds). Systema Porifera. A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 2. [1149]

General References

Bidder, G.P. 1898. The skeleton and classification of calcareous sponges. Proceedings of the Royal Society of London 64: 61-76 10 figs

Borojevic, R. 1968. Eponges calcaires des côtes de France. IV. Le genre Ascaltis Haeckel emend. Archives de Zoologie Expérimentale et Générale 109: 193-210

Borojevic, R., Boury-Esnault, N., Manuel, M. & Vacelet, J. 2002. Order Clathrinida Hartman, 1958. pp. 1141-1152 in Hooper, J.N.A. & Soest, R.W.M. Van (eds). Systema Porifera. A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 2. [1149]

Borojevic, R., Boury-Esnault, N. & Vacelet, J. 1990. A revision of the supraspecific classification of the subclass Calcinea (Porifera, Class Calcarea). Bulletin du Muséum d'Histoire Naturelle. Paris [published 1895-1906] 4 12(A,2): 243-276

Burton, M. 1963. A Revision of the Classification of the Calcareous Sponges. London : British Museum pp. 1-693 figs 1-375.

Dendy, A. 1893. Studies on the comparative anatomy of sponges. V. Observations on the structure and classification of the Calcarea Heterocoela. Quarterly Journal of Microscopical Science 2 35: 159-257 pls 10-14

Dendy, A. 1893. Synopsis of the Australian Calcarea Heterocoela, with a proposed classification of the group and descriptions of some new genera and species. Proceedings of the Royal Society of Victoria ns 5: 69-116

Dendy, A. & Row, R.W.H. 1913. The classification and phylogeny of the calcareous sponges, with a reference list of all the described species, systematically arranged. Proceedings of the Zoological Society of London 1913: 704-813

Hartman, W.D. 1958. A re-examination of Bidder's classification of the Calcarea. Systematic Zoology 7: 97-110

Hartman, W.D. 1982. Porifera. pp. 640-666 in Parker, S.P. (ed.). Synopsis and Classification of Living Organisms. New York : McGraw-Hill Vol. 1.

Hooper, J.N.A. & Wiedenmayer, F. 1994. Porifera. pp. 1–620 in Wells, A. (ed.). Zoological Catalogue of Australia. Melbourne : CSIRO Australia Vol. 12 xiii 624 pp. [Date published 21/Nov/1994]

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