Comparison of live specimens of A Hippocampus japapigu photographed off Hachijo-jima Island, Japan (Richard Smith), and its most similar congener B Hippocampus pontohi photographed off Tomia Island, southeast Sulawesi, Indonesia (Richard Smith). Note the differences in the anterodorsal area of the trunk in H. japapigu vs. H. pontohi: single vs. double pair of bilaterally paired wing-like protrusions behind the head, raised dorsal ridge vs. laterodorsal flat surface, and large and prominent vs. small eighth lateral trunk ridge spine. Abbreviations: SP-WP, single pair of bilaterally paired wing-like protrusions; DP-WP, double pair of bilaterally paired wing-like protrusions; DR, raised dorsal ridge; FS, flat dorsal surface; P-8LTR, prominent eighth lateral trunk ridge spine; S-8LTR, small eighth lateral trunk ridge spine.