Raspailia aculeata (Johnston, 1842)

Fig. 11

Halichondria aculeata Johnston 1842: 131, pl. XIII figs 1–3.

Dictyocylindrus aculeatus Bowerbank, 1866: 109 . – Bowerbank 1874: 48, pl. XIX figs 5–12.

Raspailia aculeata – Hanitsch 1894: 196. — Arndt 1935: 82–83, fig. 72.

Not Raspailia aculeata – Topsent, 1925: 682–685, pl. VIII, fig. 14. — Uriz 1978: 149–161, figs 88–94.

Not Raspaciona aculeata – Topsent 1936: 49–50.

Material examined (2 specimens)

SWEDEN • 1 spec.; Saltbacken; 59.0832° N, 11.2242° E; 51– 25 m depth; 1 Oct. 2019; Mats Larsson leg. [MM-191001-1]; SCUBA; LAR-191001-PA010107–0108, voucher: GNM Porifera 1118 • 1 spec.; Lunneviken; 59.0546° N, 11.1690° E; 51– 25 m depth; 12 Nov. 2019; Mats Larsson leg. [MM-191102-1]; SCUBA; LAR-191102-PB020290, 93; GenBank no.: OM415584 (28S D3-D5); voucher: GNM Porifera 1119 .

Description

The specimens have an encrusting morphology with digitiform projections. The colour, while alive, was dirty white or wax yellow turning white in ethanol. The surface is hispid and covered with sediment (Fig. 11A). Neither oscula nor pores were visible (Fig. 11A).

Skeleton

The skeleton is reticulated and formed by dense plurispicular fibres, with slightly curved styles, which can protrude the surface, especially at the very end of the digitiform projections. Moreover, the protruding styles often have a tyle at their end, i.e., they are often styloids. Acanthostyles are rare and present in the choanosome. The ectosome is composed by a membrane containing parallel oxeas or anisoxeas. At the base of the specimen, these oxeas/anisoxeas have a confused arrangement.

There are three types of megascleres: slightly curved styles that are often modified in styloids (Fig. 11D), measuring 619.3– 949.9 –1325.9 ± 267.97×3.4– 6.1– 12.1 ± 2.85 µm (N=8), curved anisoxeas, which can have blunt tips (rare) (Fig. 11E), measuring 253.9– 357. 2 –475.7± 62.5 × 0.8– 2.5 –4.5± 0.93 µm (N =36), and curved, fully spined acanthostyles (Fig. 10F), of 98.6– 154.1 –294.3 ±65.37 ×4.0– 6.5 – 10.1 ±1.57 µm in size (N =16).

Ecology and distribution

This species is reported in the northeast Atlantic (NEA), from North Ireland to the Azores and with a depth range from the subtidal to 15 m depth. Furthermore, there are reports of this species in the Mediterranean Sea. However, given that the morphology of the Mediterranean specimens most likely conforms to the description by Topsent (1936), which differs significantly from the descriptions of R. aculeata in (Ackers et al. 1985, according to the WPD), we doubt the Mediterranean reports to be referring to the same species.

Remarks

In the re-examination of Mr Beans’ collection, Bowerbank (1866) reported aspiculate gemmulae. However, this was never mentioned by subsequent authors. Therefore, we cannot assert that gemmulae occur in R. aculeata, nor how common they are.