Spongionella tenuis n. sp.

urn:lsid:zoobank.org:act: 1987B0F2-E9EA-4560-AADC-80272B849EF2

Figure 15

Diagnosis. Surface micropapillate from projecting fibre ends. Exopinacoderm very thin, brown.

Etymology The species name refers to the sponge’s encrusting habitus.

Material Examined Holotype RBCM 024-00016 - 001, Stn NM 411, Nine Mile Pt, Sechelt Inlet, BC, 49° 36.207’ N / 123° 47.438’ W, coll. N. McDaniel, 30 Jan 2020, 25 m depth, 1 specimen . Paratype RBCM 018-00152 - 002, Stn NM 243, Piper Pt, Sechelt Inlet, 49° 32.755’ N / 123° 47.537’ W, coll. N. McDaniel, 12 May 2011, 27 m depth, 1 specimen.

Description

External (Figure 15A) Holotype RBCM 024-00016-001 Sponge encrusting bedrock and overgrowing a haplosclerid sponge; 1 mm thick, spreading irregularly, about 4 cm wide x 8 cm long. Haplosclerid spicules are incorporated into the skeleton but not included into the fibres. Light brown-beige aspiculous exopinacoderm stretched over fibrous main body. Surface punctiform, micropapillate due to projecting ends of primary fibres; exopinacoderm missing over parts of the sponge.

Skeleton (Figures 15B, C) Ectosome: very thin brown aspiculous exopinacoderm over a fibrous choanosome. Surface perforated by closely spaced roughly round openings that connect directly to spaces between primary fibres of the choanosome and slightly raised where primary fibre ends protrude beyond the sponge surface forming micropapillae. Openings where the ectosome is in place are 1 to 2 mm across and are subcircular. Based on other Spongionella descriptions the openings may be both incurrent and excurrent with choanocytes lining the margins of the mesohyal surrounding the openings to capture food organisms.

Choanosome: aquiferous canals are polygonal; more regular just below the surface (Figure 15B). The skeleton is composed of a primary, secondary fibre networks and tertiary fibres that may branch off the secondary fibre network (Figure 15C). Primary fibres networks are polygonal, occasionally rectangular and light brown. On most primary network nodes at the top surface, fibres project outward from 0.3 to 1.5 mm. Often ends taper down toward the distal ends and may bifurcate. At the nodes of the tangential primary fibre networks branches connect at approximately 45° to the next tangential primary fibre network below. Reticulation is anistropic, approximately rectangular, 150–350 µm on a side. Primary fibres sheath a central core of concentric rings that occupy slightly more than one half the diameter of the fibre (Figure 15D). Primary fibre diameter range 14 (22) 31 µm (n=20)

Secondary fibres heel onto primary fibres where they connect. One or more secondary fibres may occur within polygons and occasionally branch and anastomose to form a vague simple mesh within the primary fibre network. Secondary fibres do not appear to be cored. Secondary fibre diameter range 5 (8) 13 µm (n=20). Occasionally translucent tertiary fibres branch off secondary fibres but do not form a third level network.

Distribution Sechelt Inlet, BC; 25–27 m depth.

Ecology Small encrustations on bedrock; only reaches the intertidal in cave environments.

Remarks There were no previously reported new Spongionella species for the North Pacific. Three were reported for the South Pacific. Spongionella monoprocta Lévi, 1961 from Vietnam, no depth information provided. Lévi’s sponge is pedunculate with a globular mass atop the peduncule. Surface is smooth with one large osculum 8 mm diameter. Primary fibres are cored with spicule debris. Two other Spongionella species were reported for Chile: ( Spongionella depressa (Ridley, 1881)) from the Straits of Magellan, 13–18 m depth and Spongionella repens (Thiele, 1905) from Juan Fernandez Island Chile, no depth information. Both are encrusting with thin, glossy dermal membranes (exopinacoderms) and both have primary, secondary and tertiary fibres, the former two forming reticulae. Ridley’s sponge has cored primary fibres. Thiele reports the primary fibres of his sponge are not cored but differ slightly in light refraction forming a layered outer and inner appearance and not laminated similar to S. tenuis n. sp.

Koltun (1959 [1971 translation]) reports two Spongionella species for Barents and Kara Seas, Laptev Sea, East Siberian Sea, central Arctic Ocean, Bering Sea, S. carteri (Burton, 1930) originally described from Norway; accepted as Spongionella pulchella (Sowerby, 1804) and S. pulchella from the Okhotsk Sea, near the Pacific coast of the southern Kuril islands originally described by Sowerby from Ireland. Koltun’s sponges were not encrusting but discoidal, flabbiform or vase-like. World Porifera Database (de Voogd, et al. 2023) notes the non-Atlantic specimens are unlikely to be Sowerby’s species.

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Spongionella tenuis n. sp. extends the known range of the genus to the Northeast Pacific from the South Pacific (east and west). Other species are reported for the Atlantic, Mediterranean, Indian Ocean, Arctic Ocean, Bering Sea and Okhotsk Sea.