Rubrafasciculus Ekins, Erpenbeck & Hooper, 2023

Ekins, Merrick, Erpenbeck, Dirk, Debitus, Cécile, Petek, Sylvain, Mai, Tepoerau, Wörheide, Gert & Hooper, John N. A., 2023, Revision of the genus Fascaplysinopsis, the type species Fascaplysinopsis reticulata (Hentschel, 1912) (Porifera, Dictyoceratida, Thorectidae) and descriptions of two new genera and seven new species, Zootaxa 5346 (3), pp. 201-241 : 226

Rubrafasciculus Ekins, Erpenbeck & Hooper gen. nov.

urn:lsid:zoobank.org:act:628D9059-A8D3-4EED-893B-FEDBD4A8F3DB

Definition. Armoured with a sparse skeleton, primary fibres are sparse and fasciculated, laminated and cored with foreign debris. Debris is often a bark on the outside of the primary fibres. Secondary fibres are laminated and often cored, and form an irregular, netlike branching network. The whole sponge has a heavy collagenous matrix.

Diagnosis. Cherry red coloured, lobate, massive, fistular, sometimes semi-buried with only the fistules showing above the sand. The sponge has apically located oscules and a conulose surface showing a regular geometric pattern. The skeleton is irregular and supported by the heavy collagenous matrix. The sponges are sparely armoured and heavily associated with sand. The primary fibres are sparse and fasciculated, laminated and cored with foreign debris. The sand sometimes forms a bark on the outside of the primary fibres. Secondary fibres are laminated and often cored, and form an irregular, netlike branching network. The primary and secondary fibres are often of a similar size, but secondary fibres may be up to half the diameter of the primary fibres.

Remarks. Rubrafasciculus gen. nov. differs from Skolosachlys gen. nov. by lacking the coring of secondary fibres and lacking the partial striated armouring. It has armouring which distinguishes it from Fascaplysinopsis as well as by lacking the axial granular thread in the secondary fibres of Fascaplysinopsis . Rubrafasciculus gen. nov. differs from all other members of Thorectinae that have armouring i.e. Aplysinopsis , Thorecta and Thorectandra by the fasciculation of primary fibres. All other genera in Thorectinae lack armouring. Petrosaspongia , which has superficial armouring, also lacks the fasciculation of primary fibres ( Table 1 ). Rubrafasciculus gen. nov. is identifiable in the field by the red colouration and the geometric pattern on the surface.

Etymology. Rubra, L. red, fasciculus L. dim. of fascis ‘bundle’

Type species: Rubrafasciculus cerasus sp. nov. here designated.