Eurypon scruposus n. sp.

urn:lsid:zoobank.org:act: C95E874A-7E02-4F64-B228-70B4D987A43B

Figure 3

Diagnosis. Thin orange sponge with sharply ridged surface and visible subdermal aqueous canals radiating from oscula.

Etymology The name refers to the sharply ridged surface of this encrusting sponge.

Material Examined Holotype RBCM 018-00130 - 001, Stn NM 311, Anvil Isl, Howe Sd, BC, 49° 31.993’ N / 123° 17.468’ W, coll. N. McDaniel, 17 Jun 2015, 20 m depth, one specimen . Paratype RBCM 018-00158 - 006, Stn NM 256, Christie Islet, Howe Sd, BC, 49° 29.919’ N / 123° 17.985’ W, coll. N. McDaniel, D. Swanston, 19 May 2011, 13 m depth, one specimen .

Description

External (Figure 3A) Holotype RBCM 018-00130-001. Encrusting, 15 cm across x 5 mm; surface uneven with subdermal aquiferous canals below circular or vaguely serpentine depressions containing oscula (apparently closed when photographed in-situ). Sponge attached to bedrock. Colour orange. Consistency easily torn.

Skeleton (Figure 3B) No specialized ectosome. The hymedesmioid choanosome is composed of multispicular tracts of long styles and tylostyles separated by lacunae of variable size. Tracts run perpendicular to the surface and are 100 to 150 µm wide. Separation is highly variable throughout the sponge from 100 to 250 µm. Where surface processes occur, spicule tracts become subplumose and penetrate the surface from 500 to 2000 μm. Near the surface tracts are composed of styles. Deeper the sponge tracts are composed of styles and a few tylostyles. Acanthostyles are scattered throughout the choanosome. At the sponge base styles and tylostyles lie at acute angles to the horizontal.

Spicules (Figures 3C, D, and E) Styles to subtylostyles, tylostyles, and acanthotylostyles. Styles to subtylostyles (Figure 3C) straight, slightly bent 1/4 from head, or curved; long sharp apices, dimension range 700– 1809 x 16.9– 42.5 µm. Tylostyles (Figure 3D) subspherical heads; shaft may be bent below the head; uncommon, 234 (399) 599 x 10.4 (13.4) 20.8 µm (n=17). Acanthotylostyles (Figure 3E) spherical heads, sparsely or unspined, tapering to sharp or slightly rounded apex, shaft completely spined, dimension range 104–255 x 17.5–32.5 µm (head width). Spicule dimensions of the two specimens examined are listed in Table 4.

n = 50 or as indicated width = head width

Distribution Currently known only from Howe Sound, BC; 20 m depth. Ecology Forms encrustations on vertical or near-vertical bedrock faces. Up to 15 cm in diameter. Remarks Eurypon scruposus n. sp. similar to the two other Eurypon species described in this report differs in skeletal architecture and spicules. Eurypon scruposus n. sp. differs from the other North Pacific Eurypon listed in Table 2 for the same reasons as E. reiswigi n. sp.