Endectyon (Endectyon) delaubenfelsi Burton (1930b) is a small, golden-coloured, stalked, bush-type sponge with a shaggy tuberculate surface. Branches are mostly in one plane and coalesce to form blades. It differs from similar branching sponges in having peculiar coarsely spined styles among its spicules (microscopic examination). It is rare, known only from SW England and Bretagne.
Colour: Golden yellow, bright orange.
Shape, size, surface and consistency: Branching-erect with a clearly differentiated stalk. Overall, the main branches tend to lie in one plane, but small branches can grow in different planes. Branching is very irregular, with a strong tendency to lateral coalescence. To about 6.5 cm in height. Surface uneven, markedly tuberculate. Velutinous, moderate friction. Oscules not visible. No contraction. No smell. Consistency soft to compact.
Spicules: (Endectyon delaubenfelsi spics) Smooth styles and acanthostyles. Most of the spicules present are smooth styles in two size categories. The short styles may be straight, or curved towards the head, 155-245 x 4-7 µm. The long styles are smooth and usually straight, 600-1060 x 6-12 µm. Occasionally styles show characteristic deformations, e.g. branching points, or a short style crossing the main one. The acanthostyles are sparsely spined, sometimes with a characteristic rosette of 4-6 spines at the head or point. They appear to be rarer than the deformed styles, and it is possible to demonstrate a transition in form between the two types of spicules. Once located in a section the shape of the acanthostyles is very distinctive. There are no microscleres.
Skeleton: Plumoreticulate with a dense axial condensation of reticulating small styles and acanthostyles, that form short bundles rising to the surface in the extra-axial skeleton. Brushes of long styles penetrate the surface.
Ecology: Specimens were found at the interface between bedrock and gravel. More habitat information is required. 25-80 m.
Distribution: Plymouth, Salcombe, Lundy, Channel Isles, Bretagne.
Etymology: Named after Prof. M.W. De Laubenfels, distinguished American spongologist of the middle of the 20th century; author of the first comprehensive taxonomic synopsis of the sponges (1936).
Type specimen information: The type is in the Natural History Museum, London. MCS voucher BELUM Mc705, Lundy Isl., SW England.
The shaggy appearance and tuberculate surface are characteristic. Another Endectyon species, E. (E.) teissieri Cabioch (1968) was described from Bretagne. It is described as having an external form more like that of Axinella flustra, an allegedly different skeleton, and long "strongyles" (drawn as somewhat blunt-ending styles) in place of the long styles. It is here assumed to be a somewhat deviating specimen of a species with insufficiently known variability.
A superficial resemblance to Stelligera rigida is possible, but the latter is more squat and bush-like, and slimy.
Burton (1930) maintains that it is impossible to differentiate Endectyon (E.) delaubenfelsi from Raspailia ventilabrum (Bowerbank, 1866: 100) externally.
Sources: Burton, 1930b; Cabioch, 1968; Ackers et al., 1992 (B.E. Picton, D. Moss).