Family OSCARELLIDAE Lendenfeld, 1887

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Introduction

Oscarellidae are Homoscleromorpha that lack any siliceous spicules or spongin fibres, having only collagenous fibrillar spongin in the mesohyl. Oscarella also differs from most other demosponges in having the external pinocoderm ciliated, and the choanocyte chambers which are spherical to ellipsoidal in shape, connect with the inhalant canal system via tiny channels (prosodi) and with the exhalant canals either directly via pores (apopyles) or via channels (aphodi).

Oscarellidae Lendenfeld, 1887 are reviewed in Lendenfeld (1903), Brien et al. (1973), Bergquist (1978), and Hartman (1982). Revisions of the family have been made by Diaz & Van Soest (1994) and Muricy & Diaz (2002).

ID Keys

KEY TO GENERA (of families Plakinidae and Oscarellidae)
(1) With inorganic (spicular) skeletal complement ----------------------------------------------------------------------------- 2
–.Without inorganic (spicular) skeletal complement ----------------------------------------------------------------------------- 6

(2) Skeleton mainly composed of diods, triods, and/or calthrops in one size class ------------------------------ 3
–.Skeleton mainly composed of diods, triods and/or calthrops with a large size variation ------------------------ 5

(3) Lophose diods, triods, or calthrops complement the main skeleton of non-lophose spicules ----------------------- 4
–.Lophose spicules absent, diactinal "microscleres" (microrhabs) present in some species---------Plakortis

(4) Heterolophose calthrops (candelabra) complement the main skeleton of non-lophose spicules, which might be absent or rare; choanocyte chambers usually aphodal------------------Corticium
–.Lophocalthrops with one to four homogeneously ramified actines complement the main skeleton of non-lophose spicules; candelabra absent; choanocyte chambers usually eurypylous ----------Plakina

(5) Skeleton composed of non-lophose diods, triods and/or calthrops in three size classes ------Plakinastrella
–.Skeleton formed by diods, triods, and/or calthrops with large size variation; the larger spicular category presents terminally-branching rays-----------------------------------------Placinolopha

(6) With sylleibid-like aquiferous system and eurypylous choanocyte chambers; ectosome thin, proportion of mesohyl to chambers ------------------------------------------- Oscarella
–.With leuconoid aquiferous system and diplodal choanocyte chambers; ectosome thick, proportion of mesohyl to chambers ----------------------------------------Pseudocorticium

Diagnosis References

Muricy, G. & Diaz, M. C. 2002. Order Homosclerophorida Dendy, 1905. Family Plakinidae Schulze, 1880. pp. 71-82 in Hooper, J.N.A. & van Soest, R.W.M. (eds). Systema Porifera: A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 1. [71]

General References

Bergquist, P.R. 1978. Sponges. London : Hutchinson 268 pp. 12 pls 81 figs 15 tables.

Brien, P., Lévi, C., Sarà, M., Tuzet, O. & Vacelet, J. 1973. Spongiaires. pp. 1-716 485 figs in Grassé, P.P. (ed.). Traité de Zoologie. Anatomie, Systématique, Biologie. Paris : Masson et Cie Vol. 3(1).

Diaz, M.C. & van Soest, R.W.M. 1994. The Plakinidae: a systematic review. pp. 93-109 in van Soest, R.W.M., van Kempen, T.M.G. & Braekman, J.-C. (eds). Sponges in Time and Space. Rotterdam : Balkema.

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.

Lendenfeld, R. von 1903. Tetraxonia. In Schulze, F.E. (ed.) Das Tierreich. Berlin : Friedländer Lf 19 168 pp. 44 figs.

Muricy, G. & Diaz, M. C. 2002. Order Homosclerophorida Dendy, 1905. Family Plakinidae Schulze, 1880. pp. 71-82 in Hooper, J.N.A. & van Soest, R.W.M. (eds). Systema Porifera: A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 1.

History of changes