Cryptostylochus sesei Soutullo, Cuadrado & Norena 2021

Cryptostylochus sesei Soutullo, Cuadrado & Noreña, 2021 Cryptostylochus sesei Soutullo et al., 2021: 364–366, fig. 1a, d–f (type locality: Playa Carbón, Las Baulas National Marine Park of Guanacaste, Costa Rica, 10°20′53.4″ N, 85°51′44.5″ W). Distribution Playa Carbón, Las Baulas National Marine Park of Guanacaste, Costa Rica. Habitat Benthic, low intertidal, under stones and sand. Remarks Cryptostylochus currently comprises four species: C. coseirensis (Bock, 1925), C. hullensis Faubel & Gollasch, 1996, C. koreensis Bulnes, Faubel & Park, 2005 and C. sesei. Cryptostylochus sensei has a dark yellow background color densely mottled with orange. It features nuchal tentacles at the end of the first third of the body, and cerebral and tentacular eyes. The male reproductive system contains a muscular seminal vesicle, a monoglandular prostatic vesicle, and a penis papilla housed in a welldeveloped heart-shaped atrium. The female reproductive system consists of an internal vagina and an external vagina, but lacks a Lang’s vesicle.