Topsent, 1896

Species Overview

Spongosorites placenta Topsent (1896) is an ill-known deep water sponge, recorded occasionally from the west coasts of Europe. It has a small-massive or lobate shape and smooth surface. The skeleton consists of a mass of oxeote spicukes of variable size and without clear structure. This sponge needs further study and its identity towards other Spongosorites species reported from the North East Atlantic needs to be established.

Taxonomic Description

Colour: presumably greyish.
Shape, surface, size and consistency: A flat massive, thick crust. The holotype in MNHN consists of two small, globular, fragments.
Surface smooth, no visible apertures. Consistency firm but friable.
Spicules:(spongos_placenta_type2.jpg) Smooth oxeas double curve, sharply pointed at the endings, large size range and probably at least two size categories, in ectosome a shorter category of approximately 70 x 5 µm, in the choanosome a relatively long and thin category 300-360 x 6 µm predominates.
Skeleton: The ectosomal skeleton is a dense mass of smaller spicules, arranged in all directions. It is detachable only as a thicker flake. Choanosome cavernous, but densely spiculated between the cavities, tracts vaguely delimited and not oriented towards the surface.
Distribution and ecology: W coast of France, probably also along most other coasts of Europe, dredged from deeper waters.
Type species information. Holotype: MNHN DT. 2409 - Concarneau, W France.

Remarks

The type was presumed to be lost by Van Soest et al. (1990), but a subsequent visit to the Paris Museum (MNHN) revealed that it still exists. Van Soest et al. (1999) synonymized Spongosorites placenta with Amorphina genitrix Schmidt, 1870. We reexamined some of Schmidt's type specimens from the Copenhagen Museum. These were definitely Halichondria as a tangential ectosomal skeleton was present. The larger spicule sizes were clearly in excess (up to 600 µm) of those of the type specimen of S. placenta. More research is necessary to distinguish Spongosorites species.
Source: Topsent, 1896; Erpenbeck & van Soest, 2002

Kingdom Animalia
Phylum Porifera
Class Demospongiae
Order Halichondrida
Family Halichondriidae
Genus Spongosorites
Species Spongosorites placenta

Status in World Register of Marine Species

Accepted name: Spongosorites placenta Topsent, 1896

Scientific synonyms and common names

Spongosorites placenta n.sp. Topsent, 1896a: 117; Erpenbeck & van Soest, 2002: 812, fig. 17.

Erpenbeck, D. & van Soest, R.W.M. 2002. Family Halichondriidae Gray, 1867. Pp. 787-816. In Hooper, J. N. A. & Van Soest, R. W. M. (ed.) Systema Porifera. A guide to the classification of sponges. 1 (Kluwer Academic/ Plenum Publishers: New York, Boston, Dordrecht, London, Moscow).

Schmidt, O., 1870. Grundzüge einer Spongien-Fauna des Atlantischen Gebietes. Engelmann, Leipzig: iv+88 pp., VI pls.

Soest, R.W.M. van, M.C. Díaz and S.A. Pomponi, 1990. Phylogenetic classification of the Halichondrids (Porifera, Demospongiae). Beaufortia, 40 (2): 15-62.

Topsent, E., 1896. Matériaux pour servir à l'étude de la faune des spongiaires de France. Mém. Soc. zool. France, 9: 113-133.

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