Hymedesmia (Hymedesmia) anvilensis, Ott & Mcdaniel & Humphrey, 2024

Ott, B., Mcdaniel, N. & Humphrey, E., 2024, Fourteen new species of demosponges (Porifera) from three coastal fjords in southern British Columbia, Canada, Zootaxa 5463 (2), pp. 151-200 : 166-168

Hymedesmia (Hymedesmia) anvilensis n. sp.

urn:lsid:zoobank.org:act:EFA8451F-5DD7-4A06-8B4D-30C2EA293B30

Figure 7

Diagnosis. Thinly encrusting, transparent exopinacoderm forms shiny surface, microconulose and papillate. Etymology The species is named after the type location: Anvil Island , Howe Sd, BC .

Material Examined Holotype RBCM 018-00148 - 003 , Stn NM 267 , Anvil Is, Howe Sd, BC, 49º 32.026’ N / 123º 17.420’ W, coll. N. McDaniel, 19 Aug 2011, 18 m depth, one specimen.

Description

External ( Figure 7A ) Holotype RBCM 018-00148-003. Sponge conulose, encrusting 3–5 mm thick, 3 cm wide, 7 cm long. Conules conical, 3 mm diameter at base, blind in preserved specimen. Small papillae 1 mm diameter at base by 1 mm high, also blind in preserved specimen. Sponge compressible, fairly easily torn. Surface shiny from a transparent exopinacoderm (dermal membrane).

Skeleton ( Figure 7B ) Basal spongin plate: Acanthostyles form a layer parallel to the base from which acanthostyles project vertically, heads down. The ectosome forms a 300 µm thick dermal membrane continuously over the sponge surface composed of subtylotes and arcuate isochelas. Subtylotes tangential to the surface and chelas densely scattered throughout the ectosome. At conules tornotes are oriented obliquely to the surface forming cones of spicules again densely scattered with chelas. The choanosome forms irregular dense multispicular acanthostyle columns connecting the basal plate and the overlying dermal membrane; columns may be plumose. Subtylotes and isochelas are scattered throughout the choanosome.

Spicules ( Figures 7C, D, E , and F) Subtylotes, acanthostyles and arcuate isochelas. Many distorted spicules present. Subtylotes ( Figure 7C ) inequiended, one end rounded, the other with an elliptical swelling, 253 (335) 384 x 7.8 (10.4) 13.0 µm. The shaft is slightly fusiform and may be polytylote. Acanthostyles ( Figure 7D, E ) are slightly curved and vary from sparsely to completely spined with the latter predominating, 162 (336) 404 x 15.6 (29.8) 49.4 µm. Uncommon strongylote and oxeote forms occur. Arcuate isochelas ( Figure 7F ) have three spatulate alae, two alae partly fused to shaft and are strongly curved; chord length 39 (47) 52 µm. Fused lateral alae are the same shape and slightly shorter than the spatulate.

Distribution Known from the type locality only, Howe Sound, BC; 18 m depth.

Ecology Forms small encrustations on bedrock up to 7 cm in diameter.

Remarks There have been several records of the subgenus Hymedesmia (H.) published for the Northeast Pacific, most only to the subgenus level ( Austin & Ott 1987, Lee et al. 2007). Austin & Ott (1987) did not provide specific location data. Lee et al. (2007) list 11 Hymedesmia (H.) for California. Table 5 below provides a list of Hymedesmia (H.) collected by, or sent to, Dr. Bill Austin over the 60+ years he studied the area sponges as well as those listed by Lee et al. (2007), one California species listed by Turner & Lohnhart (2023) and one species recorded for Russia by Koltun (1962). Only specimens reported by Austin in his web-based listing also in the Austin collection were examined; other descriptions are from the authors noted. See also Turner & Lohnhart (2023) for a brief review of Northeast Pacific Hymedesmia (H.). Table 7 lists Northeast Pacific species recorded.

All Hymedesmia (H.) species of Green & Bakus (1994) and Bakus & Green (1987) have two size classes of acanthostyles except H. (H.) sp. F versus one in H. (H.) anvilensis n. sp. Bakus & Green (1994) H. (H.) sp. F is very thin, not papillate and has a transparent ectosome. As well it is a deep-water species. Hymedesmia (H.) sp. A of Hartman 1975 has two sizes of acanthostyles. Hymedesmia (H.) sp. B of Hartman 1975 is very thin, not papillate and all spicules are shorter. Hymedesmia (H.) cf. levis Lundbeck, 1910 [of Sim & Bakus, 1986] is very thin and not papillate; spicules are shorter than H. (H.) anvilensis n. sp. Turner & Lonhart’s (2023) sponge has two sizes of acanthostyles. Hymedesmia (H.) sp. consanguinea Lundbeck 1910 and Hymedesmia (H.) sp. procumbens Lundbeck 1910 of the RBCM Austin collection both have tornotes rather than the subtylostyles of H. (H.) anvilensis n. sp. Letter-designated species of Austin are not in the RBCM collection. Koltun’s (1962) sponge has two sizes of acanthostyles.

Figures

FIGURE 7. Hymedesmia (Hymedesmia) anvilensis n. sp. Holotype RBCM 018-00148-003 (A) In-situ. (B) Skeleton cross section. (C) Tornote. (D) Fully-spined acanthostyle. (E) Sparsely spined acanthostyle. (F) Arcuate isochelas.