MORPHOLOGY AND TAXONOMY OF AMPHORA ATACAMAE FRENGUELLI (BACILLARIOPHYCEAE)

Abstract

Materials containing Amphora atacamae Frenguelli from the type locality in Chile and two localities in Argentina have been examined with LM and SEM. This diatom has narrowly lanceolate to elliptic-lanceolate frustules, semi-lanceolate to slightly triangular valves with a convex dorsal margin and concave ventral margin. The raphe is filiform and slightly curved; dorsal and ventral striae are uniseriate, composed of conspicuous, transapically elongated areolae. The girdle is composed of numerous copulae. Type material of Amphora boliviano Patrick was also studied with LM and SEM, and we conclude this species should be considered a synonym of A. atacamae. The diagnosis of A. atacamae has been emended based on our observations, and a lectotype has been selected as Frenguelli did not designate a holotype slide from his collection.