Sycon quadrangulatum ( Schmidt, 1868 )

Sycon quadrangulatum ( Schmidt, 1868) View in CoL

( Figure 6 View FIGURE 6 )

Sycandra quadrangulata Schmidt, 1868: 29 , pl. V, fig. 9.

Sycon guadrangulatum, Longo and Pronzato, 2011: 202 , fig. 102.

Material examined: ESFM-POR / 2017-434 , S19, 20 m, on stone, 3 specimens .

Description: It is usually elongated and cylindrical in shape. It reaches 5 cm in length and 1.5 cm in width ( Figure 6a View FIGURE 6 ). The body is white, greyish in color and has a hard structure. The osculum is not surrounded by spicules. Its calcareous spicules are composed of equiangular and uniangular triactines and diactines. The tubar skeleton is composed of non-congruent triactine rows (actins of equal length: 50–70 µm × 8–10 µm, actin of unequal length: 90–120 µm × 10–12 µm) ( Figure 6b View FIGURE 6 1 View FIGURE 1 , c), and the atrial skeleton is composed of equiangular triactine rows (100–150 µm × 10–15 µm). Diactines are 250–400 µm long and 18–25 µm in diameter.

Habitat and distribution: It was previously reported from rocks and crevices in the shallow sublittoral zone ( Van Soest & Weinberg 1980). In this study, only 3 individuals were found on rocks at a depth of 20 m. This species was previously reported from the eastern Atlantic Ocean and the western Mediterranean Sea ( de Voogd et al. 2024). This is a new record for the Eastern Mediterranean fauna.