Phaenomonas longissima, also known as the short-maned sand eel in St. Helena,[1] is an eel in the family Ophichthidae (worm/snake eels).[2] It was described by Jean Cadenat and Émile Marchal in 1963, originally under the genus Callechelys.[3] It is a marine, tropical eel which is known from the Atlantic Ocean, including Ascension Island, St. Helena, Brazil, Senegal, Ghana, and Cape Verde. It dwells at a depth range of 25mto35mm (82feetto115feetm), and forms burrows in sand and mud sediments on the continental shelf. Males can reach a maximum total length of 50cm (20inches).[2]