Hymetrochota austini, 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 : 168-172

Hymetrochota austini n. sp.

urn:lsid:zoobank.org:act:0E40BAB7-924C-41DC-A4BC-0057AA57388E

Figure 8

Diagnosis. Thin encrusting red sponge. Surface covered with small round craters. Oscula on tips of papillae.

Etymology Named in honour of Dr. William C. Austin, who initially identified the specimen to genus Hymetrochota .

Material Examined Holotype RBCM 018-00180 - 002 , Stn NM 283 , Knight Inlet near Lull Bay, BC, 50° 41.329’ N / 126° 02.584’ W, coll. N. McDaniel, 27 Mar 2012, 15 m depth.

Record Location / Depth Description Summary

Hymedesmia (H.) anvilensis n. sp. [this paper] BC, Anvil Is., Howe Sd. ( NM 267) / 18 m Encrusting (3 mm), papillate/conulose, yellow-orange, acanthostyles

Holotype RBCM 018-00148 - 003 162–404 x 15.6–49.4 (head width), subtylotes (many polytylote) 253–384 x 7.8–13.0, arcuate isochelas 39–52.

Austin & Ott 1987

Hymedesmia spp. NE Pacific / intertidal and subtidal acanthostyles, strongyles, subtylotes or tornotes, arcuate isochelas, sigmas may be present [no spicule dimensions].

Lee, et al. 2007

Hymedesmia (H.) sp. B of Green & Bakus 1994 S. California, Santa Barbara Channel / 120-123 m Encrusting (<0.2 mm), finely hispid, tan?, large acanthostyles 135–174 x 10–13, small acanthostyles 70–88 x 8–9, strongyles 137–195 x 3–5, arcuate isochelas 18–31.

Hymedesmia (H.) sp. C of Green & Bakus 1994 S. California, Santa Maria Basin / 75-90 m Encrusting, surface hispid, transparent?, large acanthostyles 340–580 x 21–23, small acanthostyles 130–182 x 10–13, tornotes 81–208 x 3.0–8.0, arcuate isochelas 21–34, sigmas 55–59.

Hymedesmia (? H.) sp. E of Green & Bakus 1994 S. California, Santa Maria Basin / 75-90 m Thin encrusting, surface hispid, tan, large acanthostyles 230–500 x 10–13, small acanthostyles 65–202 x 5.0–8.0, tornotes 161–200 x 3–4, arcuate isochelas 10–21, anchorate isochelas 21–26, small sigmas 10–13, large sigmas 29–49.

? Hymedesmia (H.) sp. F of Green & Bakus 1994 S. California / deep Encrusting (<0.2 mm), ectosome transparent, base light orange, acanthostyles 121–151 x 8, tylotes-subtylotes 188–242 x 5–8, arcuate isochelas 24–30.

Hymedesmia sp. Bakus & Green 1987 S. California, Santa Rosa Is. / 103 m Large acanthostyles 440–710 x 11–17, small acanthostyles 140–200 x 9.0, acanthostrongyles 70–150 x 9–11, tornotes 270–290 x 5.0, arcuate isochelas 41–46.

Hymedesmia (H.) sp. A of Hartman 1975 Central California / intertidal & subtidal; S. BC Encrusting (1.5 mm), papillate, salmon to red, large acanthostyles 120–376 x

Anthony Is. 8.0–8.5, small acanthostyles 72–112 x 6.5–7.0, tornotes–subtylotes 121–180 x 3.5, arcuate isochelas 15–30.

Hymedesmia (H.) sp. B of Hartman 1975 Central California / intertidal & subtidal Encrusting (<1 mm), salmon, acanthostyles 96–248 x 8, tylotes-subtylotes 141–204 x 5.5, arcuate isochelas 21–35.

? Hymedesmia (H.) sp. B of ( Klontz 1989) [may be S. California / intertidal Encrusting (2 mm), bright red, acanthostyles 112–360 x 8.0–12, tylotes-

Phorbus sp. ( Lee et al. 2007)] subtylotes 149–239 x4.0–6/0, arcuate isochelas 18–31.

Hymedesmia (H.) sp. cf. levis Lundbeck, 1910 [of S. California, Santa Catalina Is. / subtidal to deep; Encrusting (<1 mm), preserved light brown-yellow, acanthostyles 50–180 x

Sim & Bakus, 1986] Lundbeck: Davis Strait, the Denmark Strait and 5–10, tylotes-subtylotes 150–180 x2.4–4, arcuate isochelas 15–24.

East of the Faroe Islands / 311-1064 m

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Hymedesmia (H.) promina Turner & Lonhart, Carmel Pinnacle , California / 10–18 m Encrusting (1 mm), numerous oscula atop prominences 1–2 mm in diameter, 2023 live yellowish orange, two long acanthostyles 316–513 x 11–17, short acanthostyles 104–140 x 5–13, subtylotes 244–404 x 3–12, arcuate isochelas

27–37, sigmas 41–65.

Austin, unpublished web-based

Hymedesmia (H.) sp. cf. consanguinea Lundbeck BC, Vananda Cove / shallow; Lundbeck: Davis & Encrusting (0.5 mm), preserved white, two acanthostyles, tornotes, arcuate 1910 Denmark Strs / 1064 m isochelas [no spicule dimensions of BC specimens].

Hymedesmia (H.) sp. cf. procumbens Lundbeck BC, Soquel Bank / shallow; Lundbeck: Denmark Very thin encrusting, preserved white-pale grey, two acanthostyles, fusiform 1910 Str and S of Iceland; SE Rockall Bank —Haas tornotes, arcuate isochelas [no spicule dimensions of BC specimens]. Mounds / 252-1264 m

Hymedesmia (H.) sp. C BC, Van Anda Cove / shallow Encrusting, preserved white, acanthostyles, subtylotes to strongyles, arcuate isochelas [no spicule dimensions].

Hymedesmia (H.) sp. D BC, Portland Canal / deep Very thin encrusting, cobalt blue [no spicule data].

Hymedesmia (H.) sp. E BC, Chad Is. / intertidal Thin, small papillae, visible oscula, light green [no spicule data].

Hymedesmia (H.) sp. F BC, Chad Is. / intertidal Thin encrusting, surface rough (due to closely following substrate surface), no visible oscula, rust red [no spicule data].

Koltun 1962

Hymedes mia (H.) orientalis Koltun, 1962 [H. Kurile Islands, Russia / 320–425 m Thin encrusting (0.5 mm), large acanthostyles 270–430 x 14–18, small ( Stylopus )? [based on lack of microscleres] acanthostyles 140–170z 12–15, ectosome strongyles 220–260 x 4–7; no microscleres.

Description

External ( Figure 8A ) Holotype RBCM 018-00180-002. Sponge thin encrusting (about 1 mm) on bedrock, micropapillose, spreading indefinitely. Papillae form small round densely located craters 2 mm high by 3 mm diameter. Oscula in craters of papillae, 2 mm diameter. Red in life. Consistency easily torn.

Skeleton ( Figures 8B, 8C ) Spicule plush a palisade of styles, apices out, up to 500 µm thick, embedded in a dark brown layer of mostly vertically disposed small acanthostyles 100–200 µm thick. The top of this layer transitions to the ectosome plush where the bases of styles and tips of small acanthostyles intermix. Below this subectosomal layer is an orange pigmented choanosomal layer of variable thickness composed of large acanthostyles disposed randomly.

Spicules ( Figures 8D, E, F, G, H , and I) Styles, large acanthostyles, small acanthostyles, arcuate isochelas and birotulas. Styles ( Figure 8D ), apices slightly mucronate, shaft straight or slightly curved, slightly fusiform, 252 (298) 336 x 5.5 (8.2) 10.4 µm. Large acanthostyles ( Figure 8E ) slightly curved, nubby spines on shaft, pointed end variably aspinous, heads with longer spines (to 2 µm), oval or squared, 252 (312) 441 x 13.0 (19.4) 26.0 µm. Small acanthostyles ( Figure 8F ), slightly curved, sparsely to completely spined, sharp or rounded apices, heads rounded or squared, 101 (153) 255 x 7.8 (18.5) 26 µm. Arcuate isochelas ( Figure 8G ) 4 short alae; outer pair longest, moderately curved shaft, 20.8 (24.9) 28.6 µm; uncommon juveniles (unguiferous). Birotulas ( Figure 8H ), shaft straight or curved, teeth form umbrella-like spokes around the shaft at each end. Teeth are equidistant, and extend about 2/5ths the distance along the shaft at each end, 18.2 (23.8) 26.0 µm. (Dimensions of acanthose spicules include spines.)

Distribution Known from type locality only, Knight Inlet, BC; 15 m depth.

Ecology Forms encrustations on bedrock and barnacles up to 20 cm across. Knight Inlet has a shallow sill which causes upwelling that results in usually deep-water benthic fauna inhabiting more shallow waters based on our observations. Hymetrochota austini n. sp. may be more common in deep water in BC based on its location at the Knight Inlet fjord sill. Additional discussion about biodiversity on the sill can be found in https://www.mcdaniel. com, accessed 25 Feb. 2024.

Remarks This is the first record of a Pacific Hymetrochota and possibly a depth range extension to shallow water. There are only two other Hymetrochota described worldwide: H. rotula Topsent, 1904 from the Azores (200 m), H. topsenti ( Burton, 1930) from Norway (depth information missing) (tentative genus assignment Van Soest 2002 [2004]b). Neither Topsent, nor Burton provide skeleton descriptions. The definition of the genus (Van Soest 2002 [2004]b) is based on reexamination of Topsent’s specimen from the Azores (200 m) with a hymedesmioid skeleton and echinating acanthostyles (Van Soest 2002 [2004]b). Topsent’s sponge had a spicule complement of stylotornotes (both ends mucronate), two sizes of acanthostyles and one size of birotulas. Burton’s sponge had styles, two sizes of acanthostyles, arcuate isochelas and two sizes of birotulas. Van Soest 2002 [2004]b) tentatively based Burton’s specimen in Hymetrochota assuming the chelas were foreign. The BC specimen spicule complement is closer to Burton’s than Topsent’s but skeleton varies from strictly hymedesmioid. Isochelas in the BC specimen are common and likely not foreign. Based on the combination of thin habitus, two acanthostyles, birotulas and ectosomal styles we have placed the specimen in genus Hymetrochota . Additional specimens will be required to confirm or refute this genus assignment. Our sponge fits the definition of Iotrochotidae (Van Soest 2002 2004]b) but not strictly the genus Hymetrochota without modifying the definition to include isochelas. Hymetrochota austini n. sp. does not fit any of the other genera of the Iotrochotidae based on definitions discussed by Van Soest (2002 2004]b).

Figures

FIGURE 8. Hymetrochota austini n. sp. Holotype RBCM 018-00180-002 (A) In-situ. (B) Skeleton cross section at papilla. (C) Labelled partial skeleton cross section. (D) Styles. (E) Large acanthostyles. (F) Small acanthostyle. (G) Arcuate isochelas. (H) Birotulas (note broken alae on left image).