A Distribution maps showing the collection locations for each clade identified in B. The collection location of specimens of A. turriculata forma B identified by van der Spoel (1976) from offshore of Ternate Island is marked with a white triangle B maximum likelihood phylogeny based on the mitochondrial cytochrome c oxidase subunit 1 gene, with strong bootstrap support for four clades within the A. brunnea group. Atlanta vanderspoeli is supported as a valid species, and A. brunnea is formed of two geographically isolated clades. Bootstrap support (%) for nodes is displayed and branch lengths are proportional to the amount of inferred change, as indicated by the scale bar (mean number of nucleotide substitutions per site).