Balanus — Balanoides

The opening at the top is diamond-shaped and protected by four plates that form a "door" to prevent drying out (desiccation) during low tide.

It is famous in ecological studies for its competition with the barnacle Chthamalus stellatus . While Balanus can outgrow and smother Chthamalus in lower, wetter areas, it cannot survive as high up the shore as Chthamalus due to a lower tolerance for drying out. balanus balanoides

Common threats include whelks (sea snails) and starfish. Life Cycle and Reproduction The opening at the top is diamond-shaped and

Balanus balanoides , now more commonly known by its accepted scientific name , is a widespread species of sessile acorn barnacle. It is a dominant member of the rocky intertidal zones in the North Atlantic and North Pacific. Physical Characteristics balanus balanoides