Hymedesmia sp. 2

Pereira, Raquel, Larsson, Mats, Cárdenas, Paco & Thollesson, Mikael, 2025, Swedish marine demosponge fauna (Porifera: Demospongiae) sampled 80 years after Jägerskiöld’s inventory, European Journal of Taxonomy 983, pp. 1-64 : 41-42

Hymedesmia sp. 2

Fig. 19

Material examined

SWEDEN • 1 spec.; Lunneviken ; 59.0546 ° N, 11.169 ° E; 27 m depth; 23 Sep. 2018; Mats Larsson leg. [MM-180923-1]; SCUBA; LAR-180923-7380, 7383–7384; GenBank no.: OM436219 (coxI); voucher: GNM Porifera 1045 .

Description

The specimen, of which a 3–4 mm fragment was collected, is encrusting an algae stalk. The colour of the live specimen was yellow but turned greyish white in ethanol. The surface is smooth, and we did not observe any pores or oscula, neither in situ nor in the preserved fragment ( Fig. 19A ).

Skeleton

Due to the size and consistency of the fragment, we could not do a section. The skeleton is composed of tornotes strongyloides ( Fig. 19B ) measuring 139.2– 201.8 –239.1 ± 27.42 ×1.3– 1.9 –2.9 ± 0.54 µm (N =10), which sometimes present irregular tyles along the shaft as wide as 6 µm. In this case, the width was not measured at maximum width (in the irregular tyles) because that measure would not be representative of the spicule shape.

Remarks

The size of the tornotes and the coxI sequences are similar to those for Hymedesmia primitiva . However, the specimen lacks acanthostyles and the surface does not present any pore sieves, perhaps due the small size of the specimen. Therefore, we have not assigned the specimens to any species. Conversely, the allocation of this specimen to the genus Hymedesmia is exclusively due to the presence of the tornotes and the coxI sequence placement.

Figures

Fig. 19. Hymedesmia sp. 2. GNM Porifera 1045 (LAR-180923-7380, 7383–7384). A. Live specimen. B. Tornotes.