The polyclads (Platyhelminthes: Polycladida) from the Tropical Eastern Pacific: Commented checklist and description of a new species Author Ramos-Sánchez, Mariela 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. 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 40171C5B-90EB-4641-91FF-EA8CA2C60D23 Thysanozoon estacahuitensis Ramos-Sánchez, Bahia & Bastida-Zavala, 2020 Thysanozoon estacahuitensis Ramos-Sánchez et al. , 2020: 75–76 , figs 14a–h, 15a–g ( type locality: Estacahuite Beach, Puerto Ángel, Oaxaca ). Distribution Central coast of Oaxaca : Estacahuite Beach. This is the first record of the genus for the southern Mexican Pacific. Habitat Benthic, sublittoral ( 4 m ), under a rock, associated with seaweeds. Remarks Thysanozoon estacahuitensis has light beige background color with a black pigmentation, which is mostly concentrated along the central axis of the body. The species features sub-triangular and robust dorsal papillae with black pigmentation that diminishes towards their basal regions; the dorsal papillae are scarce, distributed mainly in the central region of the body, becoming less numerous towards the marginal and posterior region of the body. The cerebral eyes are arranged in a semicircular shape.