swimming crab (Ovalipes punctatus); sand crab
A species of crab found in sandy coastal areas. The name ヒラツメガニ is the standard Japanese common name.
I found a sand crab on the sandy beach.
Katakana spelling is standard for this species name; usually written in kana.
Kanji spelling exists but is rarely used; the katakana form is strongly preferred.
The name ヒラツメガニ literally means 'flat-claw crab', from 平 (flat) + 爪 (claw) + 蟹 (crab). The exact derivation is uncertain, but it likely refers to the shape of the claws.