### Identification Commonly known as the False Tooth Snail or Thorn Latirus, this gastropod is a visual standout on the rocky shores of the Eastern Pacific. The shell is relatively small (typically 30–50mm), characterized by a solid, globose shape and a creamy-white base wrapped in dozens of fine, chocolate-brown spiral lines. The defining field mark is the "pseudodon"—a prominent, sharp, thorn-like calcified tooth protruding from the outer lip of the aperture. Unlike similar-looking *Leucozonia* species, the *Opeatostoma*’s tooth is exceptionally long and pointed, and its spire is noticeably more depressed, giving it a "squat" profile.
### Habitat & Range You’ll find this snail clinging to life in the Tropical Eastern Pacific, ranging from the Gulf of California down to Peru and the Galápagos Islands. It favors the mid-to-lower intertidal zones, specifically rugged rocky reefs and boulder fields. During low tide, they are masters of concealment; look for them tucked deep into moist crevices or under flat stones where they hunker down to avoid the desiccating heat of the sun.
### Behaviour & Diet The False Tooth Snail is a specialized nocturnal predator. While many snails rely on brute force or acidic secretions to access prey, *O. pseudodon* is a precision specialist. It primarily targets barnacles and smaller gastropods. In the field, an observer might find them positioned directly over a barnacle colony, waiting for the cover of darkness or the returning tide to strike. They are solitary hunters, moving slowly across the substrate on a muscular foot.
### Fascinating Fact That signature "tooth" isn't used for biting or defense; it is a biological crowbar. The snail wedges the sharp spine into the opercular plates of a barnacle, prying the "doors" open just enough to insert its proboscis and consume the soft resident inside—a remarkable example of mechanical advantage in the intertidal world!