swellshark
Refers specifically to Cephaloscyllium ventriosum, a catshark found in the Eastern Pacific. Used in biological contexts.
The swellshark is a type of catshark that lives in the Eastern Pacific.
Kanji spelling is rare; the word is usually written in kana.
From アメリカ (America) + 七日鮫 (なぬかざめ, a type of shark). The exact derivation of 七日鮫 is uncertain, but it may refer to a traditional name for a similar shark.