(Montagu, 1818)

Species Overview

Desmacidon fruticosum (Montagu, 1818) is yellow massive sponge, which grows out into irregular coarse tubes in the biggest specimens. It emits copious amounts of slime when taken out of the water. Microscopically, this species is easily recognizable on the combination of oxeote tornotes (arranged into thick multispicular tracts), anchorate isochelae and sigmas, lacking any spined spicules. It is not well known and more information on its occurrence and habits is required.

Taxonomic Description

Colour: Yellow to orange.
Shape, size, surface and consistency: Massive-lobose; substantial growths often with massive tubular processes. Up to 22 cm high. The processes are simple or coalescent, oftenl fusing at the bases and so resembling malformed, band-like structures. Sometimes the thicker branches have a longitudinal groove in one side. Surface bristly. Oscules are usually small, scattered and numerous. Consistency firm, compressible. Exudes large amounts of slime when removed from the water. No smell.
Spicules: (Desmacidon fruticosum spics) Megascleres are tornotes, with oxeote or mucronate ends: 184-236 x 5-8 µm. Microscleres are spatuliferous anchorate chelae of two sizes: 15-20 and 32-49 µm, and sigmas of two sizes also: 15-20 and 50-63 µm.
Skeleton: The ectosomal skeleton consistst of bouquets of tornotes, possibly slightly shorter than those of the choanosomal tracts; there are no echinating spicules. The choanosomal skeleton is an irregular reticulation of thick multi-spicular tracts of tornotes, tracts about 100 µm in diameter, enclosing elongated meshes of 800 x 500 µm. Many loose individual spicules.
Ecology: Usually on horizontal surfaces. On mud, sand, gravel, rock, or broken shell. Recent records are from 30 m or greater depths down to 108 m.
Distribution: British Isles; France; Spain; Mediterranean.
Etymology: fruticosum (Latin) = bushy, shrubby, referring to the habit.
Type specimen information: The type is in the Natural History Museum, London: BMNH 1930:7:3:410 (dry; Spongia fruticosa type); MCS voucher MNHN Paris.

Remarks

More information is needed about this species. The skeletal net of tornote bundles with isochelae and sigmas in a massive yellow sponge which exudes slime is unlikely to be confused with other Western European sponges. The microscleres are similar to those of various Myxilla species, but lack of spined styles is a good microscopic marker to tell this apart from these species.
Sources: Ackers et al., 1985, 1992 (J.D. Guiterman, S.M. Stone, D. Moss, B.E. Picton).

Kingdom Animalia
Phylum Porifera
Class Demospongiae
Order Poecilosclerida
Suborder Myxillina
Family Desmacididae
Genus Desmacidon
Species Desmacidon fruticosum

Status in World Register of Marine Species

Accepted name: Desmacidon fruticosum (Montagu, 1818)

Scientific synonyms and common names

Spongia fruticosa n.sp. Montagu, 1818: 112, pl. XIV figs. 3-4.
Halichondria cylindracea n.sp. Bowerbank, 1882: 96, pl. VI figs. 4-8
Desmacidon fruticosum: Stephens, 1917: 9; Arndt, 1935: 73, fig. 146; Burton, 1957: 33; Lévi and Vacelet, 1958: 243; Bruce et al., 1963: 46; Borojevic et al., 1968: 19; Descatoire, 1969a: 197; Solórzano and Babio, 1979: 51; Ackers et al., 1985; 151, fig. 42.
Desmacidon cylindraceus: Arndt, 1935: 73, fig. 145.

Ackers, R.G., D. Moss, B.E. Picton and S.M.K. Stone, 1985. Sponges of the British Isles ("Sponge IV"). II. Marine Conservation Soc., Ross on Wye, U.K.: 108-197.

Arndt, W., 1935. Porifera. Tierwelt Nord.-Ostsee, IIIa: 1-140, figs. 1-239.

Borojevic, R., L. Cabioch and C. Lévi, 1968. Spongiaires. Inventaire Faune Marine de Roscoff. 44 pp.

Bowerbank, J.S., 1882. A monograph of the British Spongiadae, IV. Ray Society, London. xvii, 250 pp., 17 pls.

Bruce, J.R., J.S. Colman and N.S. Jones, 1963. Marine fauna of the Isle of Man and its surrounding seas. L.M.B.C. Memoirs, 36. 307 pp. (sponges: 42-47).

Burton, M., 1957. Plymouth Marine Fauna. 3rd ed. Porifera. Mar. Biol. Ass. U.K.: 26-36.

Descatoire, A., 1969a. Peuplements sessiles de l' Archipel de Glénan. I. Inventaire: Spongiaires. Vie Milieu, (B) 20(1,B): 177-210.

Lévi, C. and J. Vacelet, 1958. Éponges récoltées dans l'Atlantique oriental par le "Président Théodore Tissier" (1955-56). Rev. Trav. Inst. Pêch. marit., 22 (2): 225-246.

Montagu, G., 1818. An essay on sponges, with descriptions of all the species that have been discovered on the coast of Great Britain. Mem. Werner nat. Hist. Soc., 2 (1): 67-122, pls. III-XVI.

Solórzano, M.R. and C.R. Babio, 1979. Adiciones a la fauna marina de Galicia, I. Demosponjas. Bol. Inst. Esp. Ocean., 5: 43-68.

Stephens, J., 1917. Report on the sponges collected off the coast of Ireland by the dredging expeditions of the Royal Irish Academy and the Royal Dublin Society. Proc. roy. Irish Acad., 34 (B, 1): 1-16.

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