Zygantroplana ups Marcus & Harry 1982

Zygantroplana ups Marcus & Harry, 1982 Zygantroplana ups Marcus & Harry, 1982: 171–180, figs 1–3, 12 (type locality: Puerto Don Juan, Baja California, Mexico). Zygantroplana ups – González & Salazar-Vallejo 1996: 283–286, fig. 1a–d (new record from La Paz Bay, Baja California Sur). Distribution Puerto Don Juan, Punta de Malo, Bahía de los Ángeles, Baja California and La Paz Bay, Baja California Sur, Mexico. Habitat Symbiont (found in the mantle cavity of Myrakeena angelica (Rochebrune, 1895), Lottia atrata (P.P. Carpenter, 1864), L. mitella (Menke, 1847), L. dalliana (Pilsbry, 1891) and oysters of the family Ostreidae Rafinesque, 1815). Remarks The genus Zygantroplana was established by Laidlaw (1906), characterized by an oval-elongated body, absence of nuchal tentacles, a common gonopore, and lack of armament in the penis papilla (Laidlaw 1906; Marcus & Harry 1982). Currently, the genus comprises two valid species: Z. verilli Laidlaw, 1906 and Z. ups (Tyler et al. 2006–2023). Initially, the genus was placed in the family Leptoplanidae and later transferred by Faubel (1983) to the family Ilyplanidae. However, it is suggested to verify the generic status and family classification of the species, as Marcus & Harry (1982) described the presence of an interpolated granular vesicle (granule vesicle (prostate) = interpolated prostatic vesicle), a character absent in the family Ilyplanidae according to Faubel (1983), as well as an armed penis papilla with a stylet. Additionally, a review of the structure described by Marcus & Harry (1982) as uteri is recommended, as they present a morphology similar to the Lang’s vesicle found in Bivesiculoplana lamothei Pineda-López & González-Bulnes, 1984. It is also advised to conduct a thorough review of the specimens registered by González & Salazar-Vallejo (1996) as Z. ups, as the redescribed features by these authors do not match those of the nominal species.