The polyclads (Platyhelminthes: Polycladida) from the Tropical Eastern Pacific: Commented checklist and description of a new species Author Ramos-Sánchez, Mariela E9D05B3F-CF64-48E3-B5ED-8D24E47F9D2A Doctorado en Ciencias Biológico Agropecuarias, Área Ciencias Biológico Agropecuaria y Pesquera, Ciudad de la cultura “ Amado Nervo ”, Tepic, Nayarit, 63000, Mexico. & Laboratorio de Sistemática de Invertebrados Marinos (LABSIM), Universidad del Mar, campus Puerto Ángel, Ciudad Universitaria, Puerto Ángel, Oaxaca, 70902, Mexico. rmariela220@gmail.com text European Journal of Taxonomy 2024 2024-10-17 962 1 1 67 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2683/12419 journal article 10.5852/ejt.2024.962.2683 2118-9773 13947260 40171C5B-90EB-4641-91FF-EA8CA2C60D23 Paraplanocera oligoglena ( Schmarda, 1859 ) Stylochus oligoglenus Schmarda, 1859: 34 , pl. 7 fig. 77 ( type locality: South coast of Sri Lanka , Indian Ocean). Stylochus amphibolus Schmarda, 1859: 34 , pl. 7, fig. 78 (description). Planocera amphibola – Lang 1884: 444 (description). Paraplanocera oligoglena – Stummer-Traunfels 1933: 3552–3556 , figs 123–125 (new combination). — Prudhoe 1985: 109 , fig. 90 (identification keys). — Hyman 1953a: 353 , figs 118–124 (description and new record from Coronado Islands, Baja California ; Punta San Marcial reef, La Paz Bay, Baja California Sur and Miramar Beach, Sonora , Mexico ); 1954: 333 (Hilo, Hawaii); 1955a: 75–78 , fig. 4c (description and new record from Kwajalein Atoll , South Loi Island, Marshall Islands ). — Brusca 1980: 70 (identification keys). — Soutullo et al. 2021: 366–367 , fig. 2b–d (description and new record from Carbón Beach, Las Baulas National Marine Park of Guanacaste , Costa Rica ). Distribution Pantropical distribution. Sri Lanka , Christmas Island , Quobba Beach, Australia , archipelagos of Polynesia, Micronesia and Melanesia; Hilo, Hawaii, west coast of Japan . On the Mexican Pacific coast, it has been recorded in the Coronado Islands, Baja California ; Punta San Marcial reef, La Paz Bay, Baja California Sur and Miramar Beach, Sonora , Mexico ; Carbón Beach in Las Baulas National Marine Park of Guanacaste , Costa Rica . Habitat Benthic. Remarks Paraplanocera oligoglena has been recorded from the Indo-West Pacific ( Schmarda 1859 ; Stummer-Traunfels 1933 ; Hyman 1954 , 1955a ; Prudhoe 1978 ; Ken-Ichi et al . 1991 ). In the Mexican Pacific, P. oligoglena has been recorded from Isla Coronado, Baja California; Punta San Marcial reef, Baja California Sur and Playa Miramar, Sonora ( Hyman 1953a ; Brusca 1980 ; Lamothe-Argumedo et al. 1997 ); it has also been recorded from Carbon Beach, in Las Baulas National Marine Park of Guanacaste , Costa Rica ( Soutullo et al. 2021 ), therefore it is considered a circumtropical species. Paraplanocera oligoglena was described by Schmarda (1859) , as Stylochus oligoglenus , Planocera amphibola , Stylochus amphibolus . Later Stummer-Traunfels (1933) made a revision of the specimens described by Schmarda (1859) under these taxa, establishing them as Paraplanocera oligoglena . The species is characterized by an oval body with smooth dorsal coloration brown, cerebral eyes and tentacular eyes, surrounding the base of the nuchal tentacles, and a pharynx with four or five lobes. The male reproductive system features a prostatic vesicle, ducts and paired spermiducal bulbs, accessory prostatic vesicles, a cirrus sac armed with spines and a pair of conspicuous teeth, and a male atrium with a glandular pouch. The female reproductive system features a bulbous vagina, a short female atrium, an elongate oval bursa copulatrix oriented towards the anterior region of the female gonopore, with a thick muscular wall and posteriorly presenting a very scalloped lining, and an elongate Lang’s vesicle oriented towards the anterior region of the female gonopore.