Acorn barnacle
- kingdom: Animalia
- phylum: Arthropoda
- class: Maxillopoda
- order: Sessilia
- family: Tetraclitidae
- genus: Tetraclita
- species: Tetraclita squamosa
Four Cross Roads
Saint John
Barbados
Salinas
Guayas
Ecuador
La Paz
Baja California Sur
Mexico
Talisay
Caraga
Philippines
Dana Point- Isla Vista
- Malibu
- Monterey
- Pacific Grove
- San Diego
California- Provincetown
Massachusetts
United States
Charlotte Amalie
Saint Thomas Island
Virgin Islands, U.S.