Eurylepta guayota Noreña 2017, n. sp.
Creators: name: Noreña, Carolina
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Rhabditophora
Polycladida
Euryleptidae
Eurylepta
Eurylepta guayota

description: Eurylepta guayota n. sp.
(Figs. 2 and 11 A)
Holotype. Individual collected in La Maceta (19/06/2015), El Hierro, Canary Islands (Fig. 1, H3; Table 1 and 2) by Leopoldo Moro and Daniel Cuadrado. 6 slides of sagittal serial sectioned specimen and stained with AZAN; Catalogue number: MNCN 4.01 / 1190-1196.
Type locality. La Maceta, El Hierro, Canary Archipelago; in rock-pools.
Etymology. The specific name refers to Guayota. According to the native Guanche culture, a demon who life in the Teide volcano.
Occurrence in the Canary Islands. The specimen was found beneath rocks in the natural pools of La Maceta on El Hierro Island.
Description. Body shape oval. Length 1 cm. Smooth dorsal surface smooth, scarlet to dark scarlet and the coloration disappears at the body margins, becoming seemingly transparent (Fig. 2 A). Dark dots over the whole surface, more numerous in the anterior region of the body and between the tentacles. White spots only in the margin (bundles of rhabdites) and dark greyish speckles (ovaries) in the middle or central regions. Ventral sucker in the last third of the body. Very reduced marginal tentacles, laminar and triangular, 1 mm in length. The tentacular eyes are scattered at the base of and at the proximal ends of the tentacles. The cerebral eyes form two long, wide arrow-shaped rows. The rows extend from the anterior region of the brain to the anterior region of the pharynx (Fig. 2 B). Tubular pharynx, bell shaped in the anterior third of the body posterior to the cerebral ganglion. Position of the oral pore in the first third of the body and posterior to the cerebral ganglion.
Reproductive system: Single male copulatory organ, located anteriorly and in close proximity to the female system (Fig. 2 F).With a small penis papilla, armed with a short cone-shaped stylet (0.1 mm) (Fig. 2 F). Free prostatic vesicle (Fig. 2 D) and elongated seminal vesicle surrounded with circular muscles. The female copulatory organ presents a short vagina, oriented posteriorly, surrounded by bag-shaped cement glands (Fig. 2 C).
Discussion. The genus Eurylepta Ehrenberg, 1831, is characterized by the presence of true tentacles, tubular bell-shaped pharynx, mouth posterior to the brain and penis armed with a tubular stylet. It comprises 10 species (Faubel 1984). The type species Eurylepta cornuta (O. F. Muller, 1776) Ehrenberg 1831, has two varieties: E. cornuta var. melobesiarum (Schmidtlein, 1880) Lang 1884 and E. cornuta var. lobianchi (Lang, 1879) Micoletzky 1910.
Eurylepta guayota belongs to the genus Eurylepta due to the presence of the aforementioned diagnostic characters. The most conspicuous difference between Eurylepta species is based on the shape and size of the tentacles, arrangement and number of tentacular and cerebral eyes and pigmentation. Most species of the genus are yellowish to grey; however, E. aurantiaca Health & McGregor, 1912, E. rugosa Hyman, 1959 and E. cornuta are orange, garnet or red, with slight to strong translucent body margins and white dots and spots. Similar to these three species, E. guayota is scarlet to dark scarlet, but has dark spots. Eurylepta rugosa has small (rugose) papillae on the dorsal surface. The tentacles in E. aurantiaca and E. rugosa are small and rounded but elongated triangular and laminar in E. guayota. Furthermore, E. rugosa has two rounded eye cluster at the base of the small tentacles, whereas in E. aurantiaca, the eyes are within and on the entire tentacular surface. Finally, both E. rugosa and E. aurantiaca have oval cluster of cerebral eyes, whereas E. guayota has elongated arrow-shaped rows.
The arrangement of the tentacular and cerebral eyes of E. guayota remember the disposition the eyes of Eurylepta cornuta ver. lobianchi of Lang 1884, but the two elongated rows of the cerebral eyes are shorter and are extended only over the brain and not reaches the tentacular eyes clusters. The tentacles itself are very similar, but the pigmentation and the body consistency are different. E. cornuta var. lobianchi are a fragile, delicate animal, small in size with an almost transparent body with white specks, where the gut and the gut-branches are visible.
The male and female reproductive organs show characteristics of the genus.
Despite the aberrant orientation of the reproductive apparatus, this is likely caused by external factors, E. guayota display clear differences with other Eurylepta species, thus justifying the erection of a new species.
description: Published as part of Noreña, Carolina, 2017, The Polycladida (Platyhelminthes) of the Canary Islands. New genus, species and records in Zootaxa 4312 (1), DOI: 10.11646/zootaxa.4312.1.2, http://zenodo.org/record/852062