Tanystylum isthmiacum Stock, 1955

Syn.: Tanystylum isthmiacum difficile — Stock, 1966: 389–391, fig 2a–h (Brazil: Espírito Santo).— Stock, 1974: 984 (Brazil: off Pernambuco, off Pará, 51–93 m).— Stock, 1992: 121 (Brazil: Espírito Santo, 28 m). Tanystylum isthmiacum isthmiacum —Arnaud & Bamber, 1987 (non Stock, 1966).

Holotype: Unknown.

Type Locality: Isla Taboguilla, Atlantic Panama.

Tanystylum orbiculare Wilson, 1878 — Marcus, 1940c: 105 –108, pl XV fig 15a–h (Brazil: Rio de Janeiro, shallow water).— Hedgpeth, 1943: 54 –55 (Brazil: Rio de Janeiro).— Sawaya, 1949: 73 (Brazil: Espírito Santo, 35 m).— Stock, 1992: 121 (Brazil: São Paulo, intertidal).

Syn.: Clotenia orbiculare —Bouvier, 1923.

Holotype: Unknown.

Type locality: Brooklyn, New York, USA.