Weberella perlucida Austin, Ott, Reiswig, Romagosa & G, 2014, n. sp.

Weberella perlucida n. sp.

Fig. 16 A–F

Etymology. The species name derives from the translucent papillae (the literal translation of the Latin is transparent).

Material examined. Holotype: RBCM 982-64-1, NM 60, Stubbs Island, BC, (50º 36.2'N, 126º 49.8'W), 10 m depth, Aug. 30, 1976, coll. & photo N. McDaniel.

Field images lacking vouchers: RBCM 35 mm slide 3001, Helby I, Barkley Sd., BC, (approx. 48º 51′N, 125º 10′W), <30 m depth, Jul. 16, 1977, photo B. Cooke; RBCM 35 mm slide 3974, Arbutus I., Satellite Channel, BC, (48º 42.37′N, 125º 26.16′W), <30 m depth, Apr. 1977, photo, B. Cooke; Stephensen Islets, BC, (approx. 50º 34.9′N, 126º 52.4′W), <30 m depth, Sept. 1976 and May 6, 1978, 2 photos, N. McDaniel.

Description. Macroscopic features. Sponge ovoid cushion-shaped to irregularly subcylindrical; cushion shapes up to 40 mm in average diameter; subcylinders up to 150 mm long. Average thickness 20 mm. Surface covered by short cylindro-conical papillae, semi-transparent in life (Fig. 16 A). Papillae highly contractile (Fig. 16 B), and in contracted state are 1–3 mm high by about 2 mm in diam. at their base. Oscula at the summit of papillae; when expanded are 0.5 mm diam. The non-papillar surface smooth to the unaided eye. When preserved, the papillae are contracted somewhat, the oscula closed, any transparency is lost and the colour turns dull yellow. Consistency firm and cork-like. Colour in life yellow with an orange cast (Austin et al. 2012).

Microscopic features. Ectosome cortical and composed of short tylostyles, with apices directed outward. Spicules arranged in distinct columnar bundles which splay out just below the surface to form interlocking brushes (Fig. 16 C). The area between the columns forms a space below the roof of splayed out spicules. Cortex 500 Μm thick: spicules project up to 50 Μm beyond surface. Papillae formed by outfoldings of the general ectosomal surface with a central canal that leads to the osculum on the papilla summit. Cortical layer continues into the papillae. Choanosomal skeleton formed of randomly disposed spicules with no clear radial or other pattern (Fig. 16 D).

Spicules. Spicules form two classes of tylostyles, the larger in the main body (tylostyle I) and the shorter in the cortex (tylostyle II). Forty spicules of each type were measured.

Holotype. RBCM 982-64-1 Microscleres absent.

Remarks. Weberella has been considered a synonym of Polymastia by some (e.g., Koltun 1966) and not by others (e.g., Lévi 1973). Weberella is considered a valid genus in the Systema Porifera (Boury-Esnault 2002).

Our species differs from Weberella bursa Müller, 1806, the type species, as follows: the papillae are dense and the interpapillar distance is less than papillar diameter in W. perlucida n. sp. while the interpapillar distance is up to 5 times the papillar diameter in W. bursa. The small tylostyles of W. bursa do not penetrate the surface whereas in W. perlucida n. sp. they form distinct dermal brushes.

The large tylostyles are somewhat longer (450–700 µm) than those of W. bursa (340–650 µm) while the small tylostyles are somewhat shorter (90–202 µm) than those of W. bursa (125–270 µm). Weberella bursa is recorded in the NE Atlantic from the Arctic to the Iberomoroccan Gulf; from 130–960 m depth (Boury-Esnault 2002) whereas W. perlucida n. sp. is a shallow water species (10–30 m in depth) known only from BC to date.

In addition to the type species, Weberella bursa, two other species have been described: Weberella verrucosa Vacelet, 1960 and Weberella namibiensis Samaai & Gibbons, 2005. Our species differs from W. verrucosa as follows: Weberella verrucosa specimens are normally pedunculate and more hispid than in W. perlucida (Vacelet 1960, Uriz 1975). Tylostyles in the ectosome of W. verrucosa do not form columnar bundles splaying out into brushes (Uriz 1975). Choanosomal tylostyles are 350–600 µm long and those of the ectosome 100–160 µm long (Uriz 1975), while in W. perlucida they reach lengths of 700 µm and 200 µm, respectively. Weberella verrucosa is recorded from the Mediterranean at depths of 64– 100 m.

Our species differs from W. namibiensis as follows: W. namibiensis appears to be free-living without attachment to the substrate. It has only a few papillae. The primary tylostyles are larger: to 837 µm (Samaai & Gibbons 2005). The species has been recorded in shallow water (12–14 m) on the Namibian coast, Atlantic Ocean.

Conclusions. The lack of radiating choanosomal fibres and the presence of compact connective tissue in our species fits the diagnosis for Weberella. Weberella perlucida n. sp. is distinct from the three known species of Weberella.

Bathymetric range. 10 to 30 m depth.

Geographic distribution. To date only recorded in BC: Satellite Channel, Barkley Sound, Discovery Passage and Weyton Passage.

Ecology. This species is most common in current-swept habitats attached to rocky substrates in the shallow subtidal zone.