Gray, 1867
Definition: Hadromerida almost always provided with papillae or fistules (Polymastia robusta) extending from the upper surface, a few of which are exhalant and have oscules at their summit. There is a distinct cortical region with characteristic skeleton (Polymastia mamillaris skel). Most groups have only tylostyles of two or three size categories. Characteristically small-sized spicules standing erect with points out form a dense plush at the surface. Columns of large spicules radiate at the surface. Small and medium-sized spicules occur more or less commonly and at random in the choanosome between the columns. In some genera the latter may be organized in subectosomal tangential layers. In one genus thin smooth oxeas accompany the tylostyles and rhaphides occur also here and there. No microscleres.
Remarks: The following genera are recognized as valid: Polymastia , Atergia , Proteleia , Quasillina , Radiella , Sphaerotylus , Spinularia , Tentorium , Tylexocladus and Weberella . The family is most abundant in the colder and deeper waters of the world.
Source: Hooper's Internet Sponge Guide.
Genera represented in the area:
Polymastia Bowerbank, 1862 (type species Halichondria mamillaris Johnston, 1842) (syn. Rinalda Schmidt, 1870): encrusting or spherical, always with papillae; the skeleton is composed of radial bundles of principal spicules between which free spicules are scattered; there is always a cortex of at least two layers; the upper layer is always a palisade of small tylostyles; the lower layer is made of intermediary spicules tangential or perpendicular to the surface; the principal spicules may be tylostyles, styles or strongyloxeas, the intermediary spicules are most often tylostyles and the ectosomal spicules are always tylostyles; the architecture of the papillae reflects the architecture of the body. (Review: Boury-Esnault, 1987).
Quasillina Norman, 1869 (type species Euplectella brevis Bowerbank, 1862): small tylostyles form an ectosomal palisade carried by tangentially arranged intercrossing bundles of large tylostyles. Largest tylostyles form bundles irregularly crossing the large organic inner parts.
Sphaerotylus Topsent , 1898 (type species Polymastia capitata Vosmaer, 1885):
Polymastia -like sponge differing in the possession of exotyles.
Spinularia Gray, 1867 (type species Polymastia spinularia Bowerbank, 1866):
Polymastia-like sponge differing in the possession of trichodragmas.
Tentorium Vosmaer, 1885 (type species Thecophora semisuberites Schmidt, 1870): toadstool-like sponges; the basal part has longitudinal bundles of long tylostyles; these grade into diverging bundles of the upper part and the papillae; at the periphery there is a palisade of small tylostyles.
Trichostemma Sars, 1872 (type species T . hemisphaericum Sars, 1872) (syn. Radiella Schmidt, 1870): hemispherical papillate sponges with a characteristic fringe of long spicules; spiculation of Polymastia (Trichostemma hemisphaericum).
Vosmaeria Fristedt, 1885 (type species V . crustacea Fristedt, 1885): ectosomal skeleton is a crust of tangential oxeas; choanosomal skeleton consists of bundles of tylostyles; these also form the skeleton of the sharply pointed papillae.
Weberella Vosmaer, 1885 (type species Alcyonium bursa Müller, 1806): globular sponges; there is a distinct cortex, strengthened by a palisade of small tylostyles at the periphery, lying on a mass of intercrossing single spicules, here and there united in bundles making a subectosomal reticulation; in the choanosome the large tylostyles are arranged in longitudinal spicule tracts.
Species included:
Polymastia agglutinans
Polymastia conigera
Polymastia grimaldi
Polymastia inflata
Polymastia mamillaris
Polymastia robusta (= P . boletiformis )
Polymastia spinula
Polymastia uberrima
Quasillina brevis
Sphaerotylus schoenus
Spinularia spinularia
Tentorium semisuberites
Trichostemma hemisphaericum
Vosmaeria crustacea
Vosmaeria laevigata
Weberella bursa
Species not treated here:
Polymastia corticata Ridley and Dendy (1886), Azores, Brazil, cf. Boury-Esnault, 1987: 50.
Polymastia ectofibrosa Boury-Esnault et al. (1994), Straits of Gibraltar, deep water
Polymastia martae Boury-Esnault et al. (1994), Straits of Gibraltar, deep water
Polymastia mespilus Schmidt, 1873 (cf. also Thiele, 1903; Arndt, 1935), declared unrecognizable by Boury-Esnault, 1987.
Polymastia polytylota Vacelet (1969), Straits of Gibraltar, deep water
Polymastia tissieri Vacelet (1961), Straits of Gibraltar, deep water
Quasillina intermedia Boury-Esnault et al. (1994), Straits of Gibraltar, deep water
Sphaerotylus borealis (Scwartschevsky, 1906), Iceland, deep water