Pseudobiceros hymanae Newman & Cannon, 1997

Marquina, Daniel, Aguado, M. Teresa & Noreña, Carolina, 2015, New records of Cotylea (Polycladida, Platyhelminthes) from Lizard Island, Great Barrier Reef, Australia, with remarks on the distribution of the Pseudoceros Lang, 1884 and Pseudobiceros Faubel, 1984 species of the Indo-Pacific Marine Region, Zootaxa 4019 (1), pp. 354-377 : 366-367

Pseudobiceros hymanae Newman & Cannon, 1997

( Fig. 9 )

Pseudobiceros hymanae Newman & Cannon, 1997: 350 –352, figs 5A–C, 12D.

Material examined. AM W.45014, MI QLD 2434, sagitally sectioned.

Description. Elongated body is 45 mm long and 10 mm wide. Pseudotentacles are square. Dorsal colouration: purple-black background, with two marginal bands (inner to outer), wide orange and black ( Fig. 9 A). The intestinal branches dorsally project small round vesicles, of trabecular section, that open to the exterior through a pore ( Fig. 9 B) and form so-called intromittent intestinal vesicles (Faubel 1983), or “anal” pores ( Lang 1884). These vesicles are scattered all over the dorsal surface, although they are much less abundant in the anterior region, on the median line over the pharynx and copulatory apparatus. Seminal vesicle is large, pyriform, heavily muscularised and ventrodorsally oriented. Prostatic vesicle is oval, long and flattened. Ejaculatory duct is wide at proximal end, narrows near penis papilla. Prostatic duct is narrow and long. Ejaculatory and prostatic duct join inside the stylet ( Fig. 9 E). Stylet is long and conical, housed in a deep atrium. Male pores are laterally oriented; female pore are at short distance from the male apertures ( Fig. 9 C–F). The female system ( Fig. 9 F) shows the characteristic configuration of the genus.

Remarks. This is the first time that intromittent intestinal vesicles (vesicles with gastrovascular external pores) are described for Pseudobiceros . These gastrovascular external pores are similar to those present in the genus Cycloporus and Yungia aurantiaca (Delle Chiaje, 1822) (see Lang 1884). The location of the vesicles is different in each genus; in Yungia and Pseudobiceros (family Pseudocerotidae ) they are present in the dorsal surface ( Lang 1884), while in Cycloporus (family Euryleptidae ) they are restricted to the body margin ( Lang 1884; Newman & Cannon 2002; Bahia et al. 2014). Lang (1884) stated that these intestinal vesicles are used for water capture or for excretion. In P. hymanae clots of excreted material have been found near the pores of the vesicles, therefore, the function of the vesicles in P. hymanae (and in Y. aurantiaca ) may be the excretion.

In regard to the internal reproductive anatomy, P. hymanae displays significant differences with the rest of Pseudobiceros spp. examined: the ejaculatory and prostatic ducts join inside the penis papilla at a point where the stylet is present, instead of the base of the penis papilla.

On the other hand, P. hymanae presents a colour pattern similar to that of P. hancockanus , though both species can be distinguished by the external marginal bands, which is black in P. hymanae and white in P. hanchockanus . The prostatic vesicle of P. hymanae is oval and flattened, in contrasts to round prostatic vesicle of P. hancockanus .

Distribution. Previously found in Heron Island and Rottnest Island, Australia, Mandang, Papua New Guinea ( Newman & Cannon 1997) and Button Island, India ( Sreeraj & Raghunathan 2013). First report from Lizard Island, Australia.

Figures

FIGURE 9. Pseudobiceros hymanae Newman & Cannon, 1997, AM W. 45014, MI QLD 2434. A. Live specimen; B. Histological section of the dorsal surface; C – E. Histological sections of the reproductive system; F. Sagittal reconstruction of the reproductive system. Anterior to the left in B – F. Abbreviations: cp = cement pouch, ed = ejaculatory duct, fa = female atrium, i = intestine, iv = intestine vesicles, ma = male atrium, pd = prostatic duct, pv = prostatic vesicle, s = stylet, spv = spermiducal vesicles, sv = seminal vesicle.