Warty Periwinkle (Echinolittorina pascua) イボタマキビ
Warty Periwinkles are common along the High waterline on rocky areas. I had identified this as Nodilittorina trochoides but that is considered as Echinolittorina pascua now. I am not sure what this Periwinkle is called now but with names being changed there is a lot of contradictory information about. Amami 2024
If you search for イボタマキビ you will find lots of shells that look just like this. Amami 2026