Halicnemia caledoniensis, 2019

Morrow, Christine, Cárdenas, Paco, Boury-Esnault, Nicole, Picton, Bernard, Mccormack, Grace, Soest, Rob Van, Collins, Allen, Redmond, Niamh, Maggs, Christine, Sigwart, Julia & Allcock, Louise A., 2019, Integrating morphological and molecular taxonomy with the revised concept of Stelligeridae (Porifera: Demospongiae), Zoological Journal of the Linnean Society 187, pp. 31-81 : 62

HALICNEMIA CALEDONIENSIS MORROW SP. NOV.

( FIG. 15A–G)

Material examined: Holotype BELUM Mc 4307, NW of Cath Sgeir , Gigha, Firth of Lorn, Scotland, 55°39.87′N, 5°47.68998′W, 29 m, 24 June 2008, coll. B. Picton.

Paratypes: BELUM Mc 3493 E of Black Rock, Skerries, Northern Ireland, 55°13.51272′N, 6°36.54282′W, 29 m, 25 August 2006, coll. B. Picton ; BELUM Mc 3736 Labhra Cliff , Lough Hyne, Co Cork, Ireland, 51°30.0546′N, 9°18.1338′W, 12 m, 10 April 2007, coll. B. Picton ; BELUM Mc 5406 Ynys Deullyn, North Pembrokeshire, Wales, 51°57.91998′N, 5°08.45802′W, 16 m, 3 August 2009, coll. B. Picton.

L S I D: u r n: l s i d: z o o b a n k. o r g: a c t: D C E 9 F F 6 2 - 21B0-4840-9788-3C68523150A5

Description: Outer morphology: Thinly encrusting, with a hispid surface covered in silt. The holotype is ~ 15 mm × 10 mm ( Fig. 15G).

Colour: Pale yellow, Methuen colour code 3A4 ( Kornerup & Wanscher, 1978; Fig. 15G).

Choanosomal skeleton: Hymedesmoid arrangement consisting of erect, long tylostyles and bundles of long, slender, centrotylote oxeas scattered throughout the skeleton. Smaller, club-like tylostyles present in basal layer. Cells with granular content are abundant throughout the choanaosomal tissue ( Fig. 15F).

Ectosomal skeleton: Large tylostyles penetrate the surface, surrounded by supporting bundles of centrotylote oxeas. Acanthoxeas form a dense paratangential layer beneath the surface ( Fig. 15F).

Megascleres: Megascleres are very long, thin tylostyles, 1000–2800 µm × 5–7 µm (N = 6), with a base only slightly swollen (9–12 µm) ( Fig. 15A). In addition to long tylostyles, there are small club-like tylostyles, 160– 215 –340 µm × 7– 13 –20 µm at the widest part of the shaft and 13– 20 –29 µm at the base ( Fig. 15B).

Accessory oxeas: Centrotylote oxeas, with centrotylote swelling not always obvious. The oxeas are 430– 560 – 660 µm × 2.5– 3.5 –5.0 µm ( Fig. 15C–D).

Microscleres: Microscleres are angular acanthoxeas, 90– 100 –110 µm × 4– 5 –9 µm ( Fig. 15E). The spines are relatively large, ~3–4 µm in length. The term microsclere is widely used for the acanthoxeas in Halicnemia (e.g. Hooper, 2002), although they can be large (up to 110 µm in Halicnemia caledoniensis and up to 400 µm in Halicnemia verticillata ).

Reproduction: The presence of oocytes has been observed in several specimens collected between June and August.