Leptoplana mediterranea ( Bock, 1913 )

Pérez-García, Patricia, Gouveia, Filipa, Calado, Gonçalo, Noreña, Carolina & Cervera, Juan Lucas, 2024, Acotylea (Platyhelminthes, Polycladida) from the southern and western Iberian Peninsula, with the description of five new species, Zoosystematics and Evolution 100 (4), pp. 1487-1513 : 1487-1513

Leptoplana mediterranea ( Bock, 1913)

Fig. 8

Leptoplana tremellaris mediterranea Bock, 1913 .

Material examined.

• MNHNC MB 16-000100 , Station 1 , 8 September 2016, 24 mm long, sagittal sectioned into 12 slides ; • MNHNC MB 16-000113 , Station 1 , 8 September 2016, 24 mm long ; • MNHNC MB 16-000133 , Station 1 , 8 September 2016, 24 mm long ; • MNHNC MB 16-000101 , Station 1 , 8 September 2016, 22 mm long, sagittally sectioned into 3 slides ; • MNHNC MB 16-000102 , Station 1 , 8 September 2016, 23 mm long, sagittally sectioned into 4 slides ; • MNHNC MB 16-000111 , Station 1 , 8 September 2016, 18 mm long ; • MNHNC MB 16-000103 , Station 1 , 8 September 2016, 25 mm long, sagittally sectioned into 18 slides ; • MNHNC MB 16-000112 , Station 1 , 8 September 2016, 20 mm long ; • MNHNC MB 16-000115 , Station 1 , 8 September 2016, 21 mm long ; • MNHNC MB 16-000122 , Station 2 , 28 October 2018, 17 mm long, sagittally sectioned into 13 slides ; • MNHNC MB 16-000121 , Station 2 , 28 October 2018, 17 mm long, sagittally sectioned into 28 slides ; • MNHNC MB 16-000123 , Station 2 , 10 November 2018, 14 mm long, sagittally sectioned into 50 slides ; • MNHNC MB 16-000116 , Station 4 , 23 February 2019, 23 mm long, sagittally sectioned into 20 slides ; • MNHNC MB 16-000117 , Station 4 , 23 February 2019, 28 mm long, sagittally sectioned into 21 slides ; • MNHNC MB 16-000118 , Station 4 , 23 February 2019, 19 mm long, sagittally sectioned into 27 slides ; • MNHNC MB 16-000119 , Station 4 , 23 February 2019, 13 mm long, sagittally sectioned into 17 slides ; • MNHNC MB 16-000120 , Station 4 , 23 February 2019, 18 mm long, sagittally sectioned into 16 slides ; • MNCN 4.01/3968 to 3981, Station 11 , 10 May 2015, 14 mm long, sagittally sectioned into 13 slides. All of the measurements from the description refer to this specimen ; • MNCN 4.01/3382 to 3393, Station 11 , 10 May 2015, 11 mm long, sagittally sectioned into 12 slides ; • MNCN 4.01/3982 , Station 11 , 11 April 2016, 11 mm long ; • MNCN 4.01/3409 to 3416, Station 12 , 6 December 2013, 13 mm long, sagittally sectioned into 8 slides ; • MNCN 4.01/3417 to 3428, Station 12 , 6 December 2013, 15 mm long, sagittally sectioned into 12 slides ; • MNCN 4.01/3429 to 3447, Station 12 , 6 December 2013, 17 mm long, sagittally sectioned into 19 slides ; • MNCN 4.01/3394 to 3408, Station 12 , 6 December 2013, 16 mm long, sagittally sectioned into 15 slides .

Description.

Elongated worm, wider in the anterior end and narrower in the posterior end. Length between 11 mm and 31 mm (18.42 ± 4.58 mm). Ground colour of the dorsal surface, beige brownish in the pharynx area (Fig. 8 A ). Tentacles absent. A whitish colour is observed in the brain area, allowing clear observation of approx. 35 cerebral and 26 tentacular eye clusters (Fig. 8 B ). Ruffled pharynx between the first and second thirds of the body, mouth opening in the last third. Genital pores separated (approximately 0.33 mm) and located just behind the pharynx.

Reproductive system.

Male reproductive system with a true and large seminal vesicle (0.28 mm long × 0.14 mm wide), interpolated prostatic vesicle, and an unarmed penis cirrus, all enclosed in a muscular bulb (Fig. 8 F ). Vas deferens ventrally positioned, joining together before entering into the seminal vesicle. Seminal vesicle oval-shaped (Fig. 8 D ). Prostatic vesicle ventrally fastened to the seminal vesicle and separated by an epithelial common wall. Genital sucker located between the male and female pores.

Female complex simple and composed of a wide external vagina and a short and curved internal vagina. Lang’s vesicle rudimentary (Fig. 8 E, F ). Numerous shell glands surround the whole female system.

Remarks.

These diagnostic characters are present in the specimens collected during the present study, so this is the first report of the presence of L. mediterranea outside the Mediterranean.

Likewise, it is possible that the specimens found by Saldanha (1974) reported as L. tremellaris belong to L. mediterranea as well since some specimens of L. mediterranea were found close to Arrabida. However, this hypothesis needs to be confirmed with histological sections.

Biology.

Under rocks (Fig. 8 C , present study), but it was also found with Caulerpa prolifera (Chlorophyta) ( Marquina et al. 2014 a).

Distribution.

Widely distributed along the Mediterranean coasts, L. mediterranea was reported as L. tremellaris “ forma mediterranea ” in Palermo ( Grube 1840), Naples ( Lang 1884; Palombi 1936), the Gulf of Lyon ( Pruvot 1897), Trieste ( Micoletzky 1910), Port Said ( Palombi 1928), the Adriatic Sea ( Steinböck 1933), the Italian coasts ( Galleni and Gremigni 1989), and Catalonia ( Novell 2001. Tunisia ( Gammoudi et al. 2012, 2017); Mar Menor, SE Spain ( Marquina et al. 2014 a); and the southern plus western Iberian Peninsula (present study). This is the first record of L. mediterranea in Oporto ( Portugal).

Figures

Figure 8. Leptoplana mediterranea (MNCN 4.01 / 3968 to 3981) Histological sections are antero-posteriorly oriented: A. Dorsal view of the living specimen; B. Detail of the eyes; C. Example of the environment where the specimen was found; D. Histological section of the male copulatory apparatus; E. Histological section of the female copulatory apparatus; F. Sagittal reconstruction of the reproductive system. Abbreviations: cg, cemental glands; d, diverticula; ev, external vagina; fp, female pore; gs, genital sucker; i, intestine; iv, internal vagina; ma, male atrium; mp, male pore; ov, oviduct; p, penis; ph, pharynx; pv, prostatic vesicle; sv, seminal vesicle; vd, vas deferens.