Form: Massive-lobose; substantial growths often with massive tubular processes. The processes are simple or coalescent, often fusing at the bases and so resembling malformed, hand-like structures. Sometimes the thicker branches have a longitudinal groove in one side (? is this a common feature?).

Colour: Yellow to orange. Are there any other colours?

Smell: None. Slime : Exudes large amounts of slime when removed from the water.

Consistency: "Firm, compressible."

Surface: Bristly.

Apertures:

• "Oscules are usually small, scattered and numerous".

Contraction:

• Not noticeable.

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Internal characters

Skeleton: An irregular reticulation of thick multi-spicular fibres of tornotes. There is no special ectosomal skeleton nor any echinating spicules.

Spicules: The megascleres are tornotes (a), with oxeote or mucronate ends, "184-236 μm". The microscleres are spatuliferous anchorate chelae (b) of two sizes, "32-49 μm", and sigmata (c) (of two sizes also?), "29-63 μm".

Identity: More information is needed about this species. Anyone finding it is asked to record all possible information and to send it to the editors. The skeletal net of tornote bundles with isochelae and sigmata in a massive yellow sponge which exudes slime is unlikely to be confused with other UK sponges.

Distribution Map from NBN: Desmacidon fruticosum at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Desmacidon fruticosum at iNaturalist World Species Observations database.

WoRMS: Desmacidon fruticosum at World Register of Marine Species. Accepted name: Desmacidon fruticosum (Montagu, 1814). AphiaID: 133526.

Classification: Biota; Animalia; Porifera; Demospongiae; Heteroscleromorpha; Poecilosclerida; Desmacididae; Desmacidon

Voucher: MNHN Paris.

Editors: J.D. Guiterman, D. Moss, B.E. Picton.