(Bowerbank, 1866)
Species Overview
Clathria (Clathria) barleei (Bowerbank, 1866) is an irregularly lamellate-flabellate, occasionally flatttened-ramose sponge with an irregular, coarsely conulose surface. Appearance is strongly porous or punctate, and consistency is compressible. These characters are sufficient to tell it apart from lamellate shaped Axinellids. This is a northern deep water species, reaching its southern limits along the Atlantic coasts of France. Its depth range includes diving depth, but it rarely occurs in water shallower than 50 m.
Taxonomic Description
Colour: Pale beige, yellow or green. When dried, becomes orange-brown or purple.
Shape, size, surface and consistency: Massive, lamellate or with very flattened branches; irregular lamellae with conulose projections. Sizes to 20 cm high and across the base (Clathria barleei large). Surface rugose, with very porous appearance; "open" in appearance. Oscules are at the edges and on the faces of the lamellae, on conulose projections at regular intervals. Excurrent channels converging on the oscules are obvious. Pores are conspicuous and distributed fairly uniformly over the surface. Consistency fairly compressible.
Spicules: (Clathria barleei spics) Megascleres : Slender subtylostyles with microspined heads in the ectosome. Principal spicules are smooth styles, which are usually abruptly curved near the head, and taper in a fine point, size range at least 350-580 µm. Entirely spined acanthostyles, ca. 90 µm, occasionally echinate nodes in the interior.
Microscleres are palmate isochelae, ca. 18-21 µm and toxas with an abrupt central flexion, ca. 260-500 µm. Some of these categories may be absent in a given specimen.
Skeleton: The ectosomal skeleton consists of tangential, relatively slender, subtylostyles. The main skeleton is a reticulation of curved smooth styles, sparsely echinated with entirely spined acanthostyles. Very fine toxas are present in internal membranes.
Ecology: Circalittoral, on Lophelia , rocks, stones, etc. to depths in excess of 100 m, usually below 40 m.
Distribution: Arctic, southwards to west coasts of Ireland and France. Scarce within diving range, but recently recorded from Rockall; Insh Is., Firth of Lorne; Loch Sunart, Sound of Mull; and Rathlin Is., and the Maidens, N. Ireland.
Etymology: Named after the collector of the type specimen, Mr Barlee from Shetland.
Type specimen information: The type is in the Natural History Museum, London. MCS voucher BELUM: Mc490, Lunga, Firth of Lorne, Scotland.
Remarks
The lamellate/flabelliform habit is unique among European Clathria species. The compressible consistency, irregular outline, coarsely punctate surface, make this species easily distinguishable from Axinellid species like Phakellia ventilabrum , Axinella infundibulum and A . flustra . The spiculation of this species is very variable, and any of the categories toxas, acanthostyles, and isochelae, may be absent or rare in a given specimen. This has in the past caused specimens to be assigned to a variety of species, genera and families.
Sources: Van Soest and Stone, 1986; Ackers et al., 1992.