Needle-spined Urchin (Echinostrephus spc.) aciculatus Echinostrephus molaris タワシウニ
The Needle-spined Urchin is a rockboring urchin. They are small with thin spines. They live in holes that they bore in shallow water. This is Echinostrephus aciculatus or Echinostrephus molaris. They are too similar for me to tell apart. Amami 2024