Prostheceraeus moseleyi Lang, 1884

Gammoudi, Mehrez & Tekaya, Saïda, 2017, Suborders Acotylea and Cotylea (Polycladida): Study on morphological, ecological and reproductive features of some representative species from Tunisian coasts (Mediterranean), Ecologica Montenegrina 10, pp. 58-70 : 66

Prostheceraeus moseleyi Lang, 1884

Morphological features. Its general colour is milky white, greyish, speckled with white spots and numerous small dark spots, violet or black slightly more elongated in the middle of the body. The edge of the worm is a bit corrugated and bordered with orange-brown and yellow. Two marginal tentacles are present ( Fig. 1G ). Two clusters of cerebral eyes are present. Marginal tentacular eyes occur. The ventral surface shows clearly a well developed true sucker characteristic of the suborder Cotylea . The mouth lies in the anterior hind of pharyngeal cavity.

Reproductive features. Like all cotyleans, the copulatory apparatus is oriented posteriorly. The two vasa deferentia open separately in an elongated seminal vesicle. The ejaculatory canal communicates with a free prostatic vesicle via a short prostatic canal. The prostatic vesicle is provided with a smooth glandular epithelium. It is surrounded by an inner layer of longitudinal fibers muscle and a thicker outer of circular fibers. The ejaculatory canal leads to an unarmed penis papilla. The latter opens at the outside by a gonopore located at the last third of animal body.

The vagina shows a cement pouch characteristic of the Cotylea suborder. It extends vertically and then anteriorly to form the internal vagina. The internal part of vagina is provided with small vesicles serving for storage of eggs called uterine vesicles.

Figures

Figure 1. Anterior dorsal region in A: Echinoplana celerrima. See the tentacular (te) and cerebral eyes (ce) forming two paramedian bands, scale bar: 0.5 mm. B: Letoplana mediterranea. See clusters of tentacular (te) and cerebral eyes (ce), scale bar: 0.5 mm. C: Discocelis tigrina. Note the presence of cerebral and tentacular eyes clusters, scale bar: 0.5 mm. D: Imogine mediterranea. Note the presence of two everted nuchal tentacles (arrows), scale bar: 0.5 mm. E: Yungia aurantiaca. See the two marginal tentacles (arrows) and cerebral eyes spots (arrowhead), scale bar: 1 mm. F: Thysanozoon brocchii. Dorsal faces provided with papillae and developed marginal tentacles (arrows), scale bar: 1 mm. G: Prostheceraeus moseleyi. Note the presence of marginal tentacles (arrows) and yellow marginal line, scale bar: mm. H: Prosthiostomum siphunculus. The cerebral eyes (ce) are not included in the semi circle formed by marginal eyes (me), scale bar: 1 mm.