A Detailed Description of the Long-Overlooked Tunicate Ascidia protecta (Ascidiacea), Based on the Type and Non-Type Specimens from the Gulf of California

Abstract

Overlooked since its establishment, Ascidia sydneiensis protecta Van Name, 1945, originally described as having mantle musculature comprising short parallel fibers restricted to the dorsal margin, compared with musculature along the entire margin (except for a central muscle-free area) found in the so-called “A. sydneiensis group”, is treated as a full species, Ascidia protecta. A detailed examination of the type and non-type specimens of the latter, all collected from the Gulf of California, confirmed the mantle musculature arrangement in the species, as well as revealing several new features (particularly in the alimentary tract), although not supporting a protective function of the anterior tunic to retracted siphons, as suggested in the original description. A comparison of A. protecta was made with congeneric species with similar musculature.