Family POLYMASTIIDAE Gray, 1867

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Introduction

The family has undergone a molecular phylogenetic analysis, which contradicts the morphology based phylogeny and the consequent classification in place (Plotkin et al. 2017). Three genera are clearly separated, namely Polymastia, Sphaerotylus and Spinularia, but the overall results still cannot provide a satisfactory classification of the family. The only taxonomic change proposed is to abandon the genus Radiella, whose only Australian species is moved to Spinularia.

Diagnosis

Hadromerida of massive, encrusting, globular, discate or pedunculate growth form. Surface slightly velvety or very hispid. The choanoskeleton is constituted by radial megasclere tracts. A complex specialised ectosomal skeleton is developed to a greater or lesser degree in different genera. It is composed of at least a palisade of tylostyles, or oxeas and/or exotyles (cladotylostyles, spherostyles, etc.). Spicules are two or three size categories of tylostyles, subtylostyles, strongyloxeas, styles or oxeas. Free spicules are always present in the choanosome which may be intermediary or ectosomal tylostyles as well as smooth centrotylote microxeas, acanthose microxeas, or raphides in trichodragmata. A fringe of long spicules is often present at the edge of the body at the contact with the substrata. When known, reproduction is oviparous, extrusion of oocytes and sperm occurs in the sea, and after cleavage of the egg a flattened blastula larvae is developed. Asexual reproduction by the production of stalked bead-like buds has been observed. Several genera are only found in very deep and or polar waters.

ID Keys

KEY TO GENERA
(1) Polymastiidae with exotyles ------------------------------------------------------------------------------------------------ 2
Polymastiidae without exotyles ------------------------------------------------------------------------------------------------ 3

(2) Polymastiidae with grapnel-like spicules ----------------------------------------------------------------------- Proteleia
Polymastiidae with spherotylostyles ------------------------------------------------------------------------- Sphaerotylus
Polymastiidae with cladotylostyles --------------------------------------------------------------------------- Tylexocladus
Polymastiidae with acanthose tylostyles --------------------------------------------------------------------- Trachyteleia

(3) Polymastiidae with the outer layer of the ectosomal skeleton constituted by a palisade of tylostyles ---------- 4
Polymastiidae with the outer layer of the ectosomal skeleton constituted by a palisade of oxeas ----------------------------------------------------------------------------------------------------------------- Pseudotrachya

(4) Free spicules of the choanoskeleton are smooth centrotylote oxeas, acanthose microxeas or raphides in trichodragmata ------------------------------------------------------------------------------------------------------------------- 5
Free spicules of the choanoskeleton are ectosomal or intermediary tylostyles or subtylostyles ---------------------- 6

(5) Free spicules are smooth centrotylote microxeas -------------------------------------------------------------- Atergia
Free spicules are acanthose microxeas ------------------------------------------------------------- Acanthopolymastia
Free spicules are raphides in trichodragmata -------------------------------------------------------------------- Spinularia

(6) Polymastiidae with reduced choanoskeleton ----------------------------------------------------------------------------- 7
Polymastiidae with developed choanoskeleton ------------------------------------------------------------------------------ 8

(7) Choanoskeleton is reduced to bundles of free tylostyles -------------------------------------------------- Quasillina
Choanoskeleton is reduced to a layer of tangential tylostyles in its outer part --------------------------------- Ridleia

(8) Choanoskeleton is radial ---------------------------------------------------------------------------------------------------- 9
Choanoskeleton is reticulate -------------------------------------------------------------------------------------- Weberella

(9) The ectosomal skeleton is constituted by a single layer of tylostyles perpendicular to the surface ------------------------------------------------------------------------------------------------------------------------ Tentorium
The ectosomal skeleton is constituted by at least two layers ------------------------------------------------------------ 10

(10) The ectosomal skeleton from the upper part is different from the one of the lateral or lower part --- Radiella
The ectosomal skeleton is identical on the whole surface ---------------------------------------------------- Polymastia

Diagnosis References

Boury-Esnault, N. 2002. Family Polymastiidae Gray, 1867. pp. 201-219 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. [201]

General References

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

Boury-Esnault, N. 1987. The Polymastia species (Demosponges, Hadromerida) of the Atlantic area. pp. 29-66 in Vacelet, J. & Boury-Esnault, N. (eds). Taxonomy of Porifera NATO ASI Series. Berlin : Springer-Verlag Vol. G13.

Boury-Esnault, N. 2002. Family Polymastiidae Gray, 1867. pp. 201-219 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.

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).

Burton, M. 1930. Additions to the sponge fauna of the Gulf of Manaar. Annals and Magazine of Natural History 10 5: 665-676

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.

Kelly-Borges, M. & Bergquist, P.R. 1997. Revision of southwest Pacific Polymastiidae (Porifera: Demospongiae: Hadromerida) with descriptions of new species of Polymastia Bowerbank, Tylexocladus Topsent, and Acanthopolymastia gen.nov. from New Zealand and the Norfolk Ridge, New Caledonia. New Zealand Journal of Marine and Freshwater Research 31: 367-402

Plotkin, A., Voigt, O., Willassen, E. & Rapp, H.T. 2017. Molecular phylogenies challenge the classification of Polymastiidae (Porifera, Demospongiae) based on morphology. Organisms, Diversity and Evolution 17: 45–66 [61]

History of changes