Sphaerotylus verenae Austin, Ott, Reiswig, Romagosa & G, 2014, n. sp.

Sphaerotylus verenae n. sp.

Fig. 14 A–K

Etymology. verenae refers to Verena Tunnicliffe, Professor in the Biology Department and the School of Earth & Ocean Sciences, University of Victoria, who collected the samples while diving in the submersible Alvin off the coast of Washington and BC.

Material examined. Holotype: RBCM 009-00053-001, Alvin Dive A1443, Endeavour Ridge, off BC / Washington, (47º 48.5′N, 129º 07.5′W), 2220 m depth, Aug. 29, 1984, coll. V. Tunnicliffe, 1 specimen. Paratype: CMNI 2009-0027, KML 1033, Alvin Dive A1439, Endeavour Ridge, off BC /Washington, (47º 57.6′N, 129º 06.4′W), 2150 m depth, Aug. 25, 1984, coll. V. Tunnicliffe, 1 specimen.

Other material: KML 1033, Alvin Dive A1439, Endeavour Ridge, off BC /Washington, (47º 57.6′N, 129º 06.4′W), 2150 m depth, Aug. 25, 1984, coll. V. Tunnicliffe, 2 small specimens; KML 1034, Alvin Dive A1436, Rift Valley Floor, (47º 55′N, 129º 06′W), 2196 m depth, Aug. 22, 1984, coll. V. Tunnicliffe, 1 specimen.

Field images without vouchers: CSSF- ROPOS /NEPTUNE: Endeavour Ridge, (47º 57′N, 129º 06′W), off BC / Washington, 2142 m depth, Sept. 14, 2011, several specimens.

Description. Macroscopic features. (Fig. 14 A, B). The largest individual (2.0 cm) has a flattened button shape while the smaller individuals (0.9 cm) are hemispheric. One has a centrally located short papilla with an apical osculum. Colour alive white centre with dark brown peripheral band, in preservative yellowish centre with peripheral brown band.

Microscopic features. The ectosome is composed of a dense layer of tangentially arranged medium and small tylostyles with an outer layer of vertically aligned small tylostyles to form a palisade (Fig. 14 C). In at least the preserved material this layer is quite tough except in the central region which is soft and easily macerated. This region lacks the layer of tangentially arranged tylostyles. Exotyles project from the ectosome in radiating tufts except in the central area where they are absent. The bases of the exotyles are anchored in the tangential layer. The choanosome includes tracts of large subtylostyles extending to the ectosome (Fig. 14 C).

Spicules. Spicule types include exotyles, and three classes of subtylostyles/tylostyles. The exotyles have smooth, not granulated heads, and are blackened along part of their length. They are cone shaped; the wide top of the cone rounded, and the narrow bottom of the cone ending in a bulb or subtyle. A few exotyles have slightly inflated heads.

Holotype RBCM 009-00053-001 Remarks. Table 9 includes the Sphaerotylus species recorded in the Porifera Data Base (van Soest et al. 2012). Sphaerotylus verenae n. sp. differs from the other eight species in having smooth rather than rough exotyle heads. Otherwise, it is similar in spicule forms and size range to S. capitatus (including S. schoenus). The exotyles in S. verenae n. sp. are somewhat longer than the Antarctic S. vanhoeffen and the raphid bearing S. raphidophora, and are much longer than in S. sceptrum and S. exotylotus. They are much shorter than in S. antarcticus and S. borealis.

Conclusions. Koltun (1966) in his description of S. capitatus (as S. schoenus) stated that the head of the exotyles is usually rough and finely dentate. Boury-Esnault (2002) described the exotyle head of S. capitatus as a slightly spiny sphere. The spination or roughening is evident in her photograph of type material (Fig. 4 D, p. 206). The exotyle heads that we observed in five Endeavour Ridge specimens were invariably smooth under both the light microscope and with SEM. We consider this is a sufficient difference to propose that this material represents a new species S. verenae n. sp.

Bathymetric range. From 2150–2220 m depth.

Geographic distribution. Endeavour Ridge off the British Columbia /Washington coast.