Emprosthopharynx opisthoporus Bock, 1913

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 : 34

Emprosthopharynx opisthoporus Bock, 1913

Emprosthopharynx opisthoporus Bock, 1913: 161–165 , figs 28a–b, 29–30, pl. 5 fig. 9 (type locality: Galapagos Archipelago, Ecuador).

Emprosthopharynx opisthoporus – Bock 1925: 48, 61–63, 84, figs 18–22, pl. 2a figs 5–7 (description).

Distribution

Galapagos Archipelago, Ecuador; Taboga and Taboguilla Islands, Panama; Gilbert Islands, Kiribati, Indian Ocean.

Habitat

Ectocomensal (associated with the shell of Petrochirus californiensis Bouvier, 1895 ).

Remarks

Emprosthopharynx opisthoporus is a species characterized by a translucent yellow coloration with a brownish body margin (postfixation coloration), cerebral, tentacular and submarginal eyes, the latter distributed in the first third of the body. The pharynx is located in the first third of the body, oriented towards the anterior region. The separate gonopores are positioned in the last third of the body. The male reproductive system features an oval seminal vesicle and an interpolated prostatic vesicle oriented towards the anterior region of the body, and a conical, short and inert penis papilla. The female reproductive system has a vagina oriented towards the posterior region of the body (it is worth mentioning that the female structures of the species were not fully developed).

Emprothopharynx opisthoporus was described by Bock (1913) and collected as a free-living species, which shares substrate with Petrochirus californiensis in the Galapagos Archipelago. Subsequently, it was later recorded in Panama associated with the shell of P. californiensis on Taboga Island; Emprothopharynx opisthoporus are located on the sand and in the Taboguilla Islands on the same pagurid at 9 m depth; he determined the association as ectocommensalism, he observed that the polyclad lodges in the cavity of the shell, to move away from the light and seek protection; later Bock (1913) recorded the species in the Gilbert Islands; however, he did not make a detailed description of the specimens ( Prudhoe 1968).