Oceanapia polytuba n. sp.

urn:lsid:zoobank.org:act: 9D2B6493-B783-454C-B579-54762F5D81BA

Figure 13

Diagnosis Hemispherical with erect, hollow fistulae of varying diameter each terminated with a single osculum; fistulae may be simple or bifurcated. Ectosome is a vague reticulation of oxeas. Choanosome an irregular reticulation of oxeas; primary oxea tracts variably present or absent alternating with the choanosome reticulation, ascending toward the ectosome. Oxeas 150–240 by 5–15 µm; no microscleres.

Etymology The species name refers to the multifistulate habitus.

Material Examined Holotype RBCM 016-00055 - 001, Stn NM 248, Nine Mile Pt, Sechelt, BC, 49° 36.216’ N / 123° 47.396’ W, coll. N. McDaniel, 12 May 2015, 5 m depth, 1 specimen . Paratypes RBCM 018-00122 - 001, Stn NM 298, Nine Mile Pt, Sechelt Inlet, BC, 49° 36.216’ N / 123° 47.396’ W, coll. N. McDaniel, 7 Jan 2015, 9 m depth, 1 specimen; RBCM 018-00123 - 001, Stn NM 299, Nine Mile Pt, Sechelt Inlet, BC, 49° 36.216’ N / 123° 47.396’ W, coll. N. McDaniel, 28 Jan 2015, 9 m depth, 1 specimen; RBCM 018-00391 - 001, Stn KML 137A/75, Execution Rock Cave, Barkley Sd ., BC, 48° 49.9’ N / 125° 10.7’ W, coll. W.C. Austin, 1975, intertidal, 1 specimen; RBCM 018-00249 - 001, Stn KML 45/76, Ross Islets, Barkley Sd ., BC, 48° 52.5’ N / 125° 09.5’ W, coll. W.C. Austin, 20 Apr 1976, 10 m depth, 1 specimen . Other Material Stn MHLO 36, Schooner Cove, BC, 49° 17.18’ N / 124° 7.62’ W, coll. R. Harbo, 26 Jul 1975, 10 m depth, 1 non-voucher specimen .

Description

External (Figure 13A) Holotype RBCM 016-00055-001 Encrusting, multi-fistulate with fistulae arising perpendicularly from a common base. Sponge 12 cm across; base 5 mm thick, very porous. Fistulae of widely varying lengths and diameters, 5–10 mm diameter, 10–25 mm high, simple or bifurcated, most simple with a terminal single osculum, 3–8 mm diameter; most bifurcated fistulae blind. Ostia not visible. Surface microhispid. Colour in life and alcohol cream; fistulae semi-translucent. Consistency soft, spongy, fairly easily torn.

Habitus of specimens examined varies from encrusting to hemispherical.

Skeleton Ectosome (Figure 13B, C) Near the surface the primary tracts (if present) end and the reticulation is more open and regular; distance across the reticulations approximately 200 µm. Reticular skeleton continues into the fistula supporting the wall; fistulae are hollow. Single or double spicules penetrate the surface up to 200 µm. Choanosome of the main sponge body (Figure 13D) irregular reticulation of oxeas with or without multi-spicular primary tracts. Primary tracts branching and anastomosing irregularly, formed of 3–5 thick bundles of oxeas spaced variably 200–500 µm apart. Reticulation formed by single to double spicules at variable angles between the primary spicule tracts; distance across the reticulations is highly variable, 30–200 µm. Primary tracts may be very vague or absent in some specimens. Lacunae in choanosome up to 1 mm across.

Spicules (Figure 13E) Spicules are exclusively oxeas, slightly curved with acerate, slightly mucronate apices, dimension range 123–263 x 2.5–15.0 µm. There is no distinguishable difference between oxeas in the fistulae and the main sponge body. No microscleres. Table 13 lists dimensions of specimens examined.

Distribution Known from southern BC (Jervis Inlet, Sechelt Inlet, Strait of Georgia, Barkley Sound), + 0.5 to 20 m depth.

Ecology The sponge grows on sediment or hard substrates in habitats exposed to a range of tidal currents. In areas of strong current, the sponge is low-growing with short fistulae, while those in quiet waters grow more upright with taller fistulae. It is also found in cave tide-pools on exposed coastlines. Oceanapia polytuba n. sp. is a common shallow water sponge encountered in SW BC. It is not found intertidally except in cave environments.