Form: Varies from sheets or cushions of unequal thickness to massive-lobose. The lobes may become elongate and anastomose, leading to a superficially ramose appearance. Specimens can grow to a considerable size - at least 10cm diameter and thickness.
Colour: Yellow, yellow green. "A live, ochrous yellow (never red)"; "pinkish grey". "Preserved, white to light brown".
Smell: Quite marked: sweetish-pungent(!)
Consistency: Firm to soft, even. "Firm, compressible".
Surface: Typically covered by small conules, raised up by the skeletal fibres, giving the surface a somewhat reticulate appearance.
Apertures: "Oscules few, large when open, found at summits of the lobes or scattered and carried on membraneous fistules on encrusting forms".
Contraction: Slight in encrusting form.
Skeleton: Plumoreticulate. The main skeleton is an irregular reticulation of multispicular fibres. The ectosomal skeleton is a tangential, comparatively feeble, triangular or polygonal reticulation of multispicular fibres. Spongin reinforces the skeletal fibres to a varying degree.
Spicules: The megascleres typically are slightly curved (sub)tylostyles (a), thicker towards the pointed end, with a more or less pronounced head; length 220-(275)-320Ám, varying between individuals. The microscleres includes palmate isochelae in 3 size groups. The largest (b) are ca. 31-47Ám and, when present in any numbers, are grouped into rosettes in the surface. The middle size (ca. 12-25Ám) are solitary and variable in number (and may even be absent). The smallest isochelae (c) are solitary, often abundant, with one tooth characteristically standing out from the shaft giving the spicule a noticeably angular profile, ca. 13-15Ám. Sigmata (d,e) (of two sizes?) are present. The larger are numerous, robust and somewhat twisted, sizes generally in the range 40-65Ám. The smaller (if present) are thinly scattered and very slender and consequently sometimes hard to find, ca. 16-22Ám. They were not present in the material examined here, though both thick and thin large sigmata were present. Toxa (f) are either single and scattered or, nearly always, in small bundles forming toxodragmata. They are small (ca. 20-70Ám) and fine, with a widely extended central flexion. They are always present but sometimes rare and difficult to detect.
Habitat: "Littoral to 37m, growing on stones, shells, algae, sessile coelenterates and Chlamys varia". On boulders, cobble, at sheltered sites with moderate tidal streams.
Distribution: "British Isles. Common along the Atlantic coast of France and Spain; Mediterranean". Azores.
Distribution Map: NBN map : National Biodiversity Network mapping facility, data for UK.
Identity: The appearance alive is distinctive but probably not diagnostic. That, combined with a microscopic examination, should provide a ready identification; cf. Mycale macilenta (q.v.).
Voucher: BELUM : Mc1620. Lough Hyne, Cork.
Editors: D. Moss, B.E. Picton.
|Picton, B.E., Morrow, C.C. & van Soest, R.W.B., 2011. [In] Sponges of Britain and Ireland |
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