Eulatocestus galapagensis (Hyman, 1953)

Ramos-Sánchez, Mariela, 2024, The polyclads (Platyhelminthes: Polycladida) from the Tropical Eastern Pacific: Commented checklist and description of a new species, European Journal of Taxonomy 962 (1), pp. 1-67 : 18

Eulatocestus galapagensis (Hyman, 1953)

Latocestus galapagensis Hyman, 1953b: 183–185 , 198, figs 1–2 (type locality: Black Beach, Floreana Island, Galapagos Archipelago, Ecuador).

Eulatocestus galapagensis – Faubel 1983: 64 (new combination).

Distribution

Black Beach, Floreana Island, Santiago Island and south of Seymour Island, Galapagos Archipelago, Ecuador.

Habitat

Benthic.

Remarks

Hyman (1953b) initially described the species as Latocestus galapagensis ; however, Faubel (1983) transferred it to the genus Eulatocestus based on the morphology of the prostatic vesicle. The latter exhibits a thick glandular coating, consisting of a network of follicles (see Hyman 1953b: 199, fig. 2); whereas in the genus Latocestus Plehn, 1896 , the prostatic vesicle shows a rigid and irregular glandular lining or digitiform (see Hyman 1953a: 276, fig. 3).

Eulatocestus galapagensis has an elongate, grayish-brown body, the body margin surrounded by a band of marginal eyes, cerebro-frontal eyes arranged in two bands, and frontal eyes arranged in a fan-shaped pattern between the brain region and the anterior end. The pharynx is located in the last third of the body. The gonopores are located at the end of the posterior region of the body. The male reproductive system features spermiducal vesicles and spermiducal ducts oriented towards the anterior-posterior region of the body, oval free prostatic vesicle, and an inert conical penis papilla. The female reproductive system features a vagina and an oval Lang’s vesicle, oriented towards the posterior region of the body.