Pycnogonida from the mediolittoral and infralittoral zones in the tropical western Atlantic

Twenty-seven species of Pycnogonida are recorded from the mediolittoral and infralittoral zones in the West Indies and of the north coast of South America, including two new species. Eurycyde acanthopus n. sp. was found on the shelf off the coast of Venezuela. Anoplodactylus monotrema n. sp. is widely distributed in the area; it has apparently been confused in the past with A. robustus (Dohrn, 1881). The morphology of the latter, and of the closely related A. virescens (Hodge, 1864), is discussed. Material from Amsterdam and St. Paul islands (Indian Ocean) attributed to A. virescens, is considered to belong to a separate species, A. dentimanus. – The range of several species is extended. Two species of Endeis, viz. E. meridionalis (Bohm, 1879) and E. biseriata Stock, 1968, were found for the first time in the Atlantic Ocean; formerly they were recorded from the Indo-West Pacific only. An Achelia is provisionally identified as A. langi (Dohrn, 1881), a species hitherto known from the eastern Atlantic and the Mediterranean. — The male of Tanystylum isthmiacum difficile Stock, 1966, is illustrated for the first time; it is concluded that T. isthmiacum and T. geminum Stock, 1954, do not form a pair of vicarious species. The male sex of Ammothella exornata Stock, 1975, is also recorded for the first time.