Thysanocardia procera Moebius 1875

Thysanocardia procera (Moebius, 1875)

Description. Body yellow and yellowish-red in colour, with circular base and rounded point. Trunk 2.5–6.2 mm long, 1.3–1.8 mm wide. Introvert 3.8–16 mm long, 0.5–0.9 mm wide. 7–9 tentacles surrounding bilobed nuchal organ (Fig. 4 B). Distinct brown line present on oral surface of tentacle (Fig. 4 B). Papillae on posterior end of trunk 17.5–40 µm height, 10–25 µm in diameter; papillae on anterior part of trunk 17.5–27.5 µm height, 7.5–15 µm in diameter. Contractile vessel with distinct villi. Distance between posterior end of trunk and base of retractors 0.25–1 mm. Retractors originating from 10–16% of distance to end of trunk. Nephridiopores at same level to anus. Nephridia 1–1.5 mm height, 0.2–0.3 mm wide. Trunk 2.5–4.1 times nephridia length.

Ecology. In the study area, this species was found on sandy-mud, muddy-sand and Posidonia oceanica between 15– 30 m.

Distribution. North Atlantic and Mediterranean Sea (Saiz Salinas & Villafranca Urchegui 1990).