Prostheceraeus vittatus (Montagu, 1815) Lang, 1884

Norena, Carolina, Marquina, Daniel, Perez, Jacinto & Almon, Bruno, 2014, First records of Cotylea (Polycladida, Platyhelminthes) for the Atlantic coast of the Iberian Peninsula, ZooKeys 404, pp. 1-22 : 6-8

Prostheceraeus vittatus (Montagu, 1815) Lang, 1884 Figure 4

Material examined.

Two specimens captured in winter 2010 and 2012 (15/03/2010 and 24/02/2012). Voucher: one specimen sectioned sagittally, stained with Azan and deposited in the Invertebrate Collections of the MNCN; Cat. Nr: MNCN 4.01/648 to 4.01/662 (15 slides).

Description.

Elongated worms 10-30 mm long and 7-15 mm wide. Body shape elongated, leaf-shaped, with pointed anterior and posterior ends, and with light undulating margins. Marginal tentacles well developed with whitish edges and pointed ends. Dorsal surface smooth. Background coloration whitish or ivory, with black, continuous stripes; between the stripes, black discontinuous lines are present (Figure 4C). Faint white band runs along the entire body margin (Figure 4A, B). Ventral side smooth and pale. Sucker in middle of body or slightly more posterior (Figure 4E). Cerebral eyes form two compact elongated, frontally anastomosing groups (Figure 4A). Tentacular eyes scarce and mainly at base of tentacles. Tubular pharynx near anterior end, oral pore in posterior region first quarter of the body. Male and female genital pores clearly separated and located behind the pharynx (Figure 4D, E).

Male copulatory apparatus with antero-dorsally oriented prostatic vesicle (Figure 4D, E). Male system consists of a short penis papilla armed with a small conical stylet, a true prostatic vesicle with a smooth glandular epithelium and a seminal vesicle with a thick muscle layer. Vasa deferentia join a dilated common vas deferens that opens into seminal vesicle. Copulatory complex lies forwardly oriented, and seminal vesicle opens through a small duct directly into distal end of prostatic vesicle.

Female system lies posterior to male pore and is characterized by a short, rounded female atrium and a cement duct or pouch. In our specimen, a second dilatation (so-called shell gland pouch) follows the atrium, into which shell glands open. Posteriorly-orientated vagina and numerous uterine vesicles are situated medially to this pouch.

Biology.

Prostheceraeus vittatus feeds mainly on Clavelina ascidians, as other Prostheceraeus species (Figure 4B).

Remarks.

Lang (1884) mentions in the original description that specimens less than 1.5-2 cm in length were immature. However, sometimes our specimens from the Atlantic coast were mature, despite their small size (c. 1.5 cm in length).

Distribution.

Two specimens of Prostheceraeus vittatus were captured during this study. The first animal was collected from "A Tiñosa” (Ria de Arosa, Galicia, Spain) on a rocky bottom between Clavelina lepadiformis colonies, at a depth of 24 metres (42° 32.8240N, 008° 57.9920W). The other worm was found on stones in “Petón Bajo" (Ria de Arosa, Galicia, Spain), at a depth of 16 metres (42° 32.9880N, 008° 57.9920W).

Prostheceraeus vittatus is known from the North Atlantic coasts of the United Kingdom, France, Ireland, Scandinavia, Norway, Denmark, from the Mediterranean shores in Italy (Gulf of Naples) ( Faubel and Warwick 2005) and Spain (Catalonia) ( Novell 2003). This is the first record for the species from the North Atlantic side of the Iberian Peninsula.