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 Pseudobiceros splendidus ( Lang, 1884 ) Pseudoceros superbus Lang, 1884: 540 , pl. 5 fig. 5, pl. 21 figs 2, 14, pl. 22 figs 1–3, 6, pl. 30 fig. 18 ( type locality: Mediterranean). Pseudoceros evelinae Marcus, 1950: 81–84 , 178, pl. 18, figs 152–157 (description, record form Forte de Itaipú, Santos, São Paulo , Brazil ). Pseudobiceros periculosus Newman & Cannon, 1994: 251–252 , fig. 40a–c (description, new record from North Heron Island, Great Barrier Reef, Australia ). Pseudobiceros hymanae Newman & Cannon, 1997: 350–352 , figs 5a–c, 12d (description, record from Heron Island, Great Barrier Reef, Australia ). Pseudoceros superbus – Plehn 1896: 171 (new record from Galapagos Archipelago). — Verrill 1900: 596 , pl. 70 fig. 5 (new record from Bermuda ). Pseudoceros splendidus – Stummer-Traunfels 1933: 3487 (new combination, new name). — Hyman 1939c: 19 , 24; 1955c: 137 (new record from Ricon Beach, Puerto Rico ). — Prudhoe 1989: 87 (new record from Mozambique , Africa). Pseudobiceros evelinae – Faubel 1984b: 216 (new combination, identification keys). — Bahia et al. 2014: 506 , fig. 9a–i (description, new record from Praia das Conchas, Cabo Frio, Brazil ( 22°52′33.05″ S , 41°58′39.27″ W ). — Litvaitis et al. 2019: 883–888 (new combination). Pseudobiceros splendidus – Faubel 1984b: 216 (new combination, identification keys). — Litvaitis et al. 2019: 883–888 , fig. 9a (new record from Mid Turtle Shoal, Hawk Channel, and Fort Pierce, Florida , USA ). Pseudoceros evelinae – Litvaitis et al . 2019: 883–888 , fig. 9 (new combination). Pseudobiceros periculosus – Litvaitis et al. 2019: 883–888 , fig. 9c (new combination). Pseudobiceros hymanae – Litvaitis et al. 2019: 883–888 , fig. 9b (new combination). Distribution Pantropical distribution. This species appears to be widely distributed, having been recorded in the Mediterranean, Bermuda , Florida, Puerto Rico , Brazil , Mozambique , Vietnam and the Galapagos archipelago. Habitat Under rocks and associated with colonial ascidians (botrylloid compound, family Didemnidae Giard, 1872 and of the genus Symplegma Herdman, 1886 ) and dark purple sponges (Verril 1900; Bahia et al. 2014 ). Remarks Pseudobiceros splendidus is part of a group of pseudocerotids ( Newman & Cannon 1997 ) characterized by a black dorsal coloration with an orange submarginal band and black border (review Litvaitis et al . 2019 ), and small white dots on the dorsal surface ( Lang 1884 ). The species was initially described as Pseudoceros superbus by Lang (1884) and later renamed Pseudobiceros splendidus by Stummer-Traunfels (1933) to avoid confusion with another species of the same name ( Marcus 1950 ). Subsequently, transferred to Pseudobiceros by Faubel (1984b) , due to its double male reproductive system. Litvaitis et al. (2019) , based on molecular analysis and coloration pattern, established Pseudobiceros periculosus , Pseudobiceros evelinae , and Pseudobiceros hymanae as junior synonyms of Pseudobiceros splendidus .. Its geographic distribution suggests it may be one of the few truly cosmopolitan polyclads species and evidence of strong intraspecific cohesion.