The titan acorn barnacle is a large species with calcareous plates forming a steep-sided cone which grows to a height and width of 5 centimetres (2.0 in).

[3] The native range of the titan acorn barnacle is the Pacific coasts of Central and South America from Mazatlán, Mexico to the Ecuador/Peru border.

Fossil specimens of this barnacle have been found in rocks dating back to the Oligocene and it occurred in Baja California in the Pliocene at a time when that area was 480 kilometres (300 mi) further south.

[6] The titan acorn barnacle is a suspension feeder, extending its cirri (modified legs) from the aperture at the top of the shell to catch plankton.

They are gregarious and tend to settle near others of their species on rocks, on new man made structures such as cables, buoys and the hulls of boats, and also on the shells of bivalve molluscs.