Prostheceraeus roseus Lang, 1884 Figure 7A, B

Remarks.

Prostheceraeus roseus belongs to the family Euryleptidae and is characterized by the following: an elongated, oval body shape and smooth surface; conspicuous marginal tentacles; cerebral eye clusters in two small, parallel rows that do not anastomose. This species is readily recognizable by its distinct pink to purple pigmentation with white longitudinal stripes and a white edge that runs along the entire body margin. The tubular, bell-shaped pharynx oriented frontally, and the digestive system well developed with numerous, anastomosing branches. The reproductive system shows the characteristics of the genus: male copulatory apparatus frontally oriented; penis armed with tubular pointed stylet and female complex with multiple uterine vesicles.

Distribution.

Prostheceraeus roseus was one of the first species collected during this study, first in summer of 2010, then in autumn of 2013 (14/05/2010 and 10/10/2013). Two specimens were captured in the mouth of the Ria de Arosa in Corrubedo: one on a rocky wall in “Canteiro”, at a depth of 27 metres (42° 30.5540N, 009° 05.1260W), and the other on Pycnoclavella producta ( Ascidiacea) in "A Dianteira", at a depth of 23 metres (42° 30.9100N, 009° 04.3750W). Prostheceraeus roseus is also known from the Gulf of Naples, Italy (Lang 1884). These findings represent the first record for the Atlantic coast outside the Mediterranean Sea.