A smasher of about 10 cm (4 in), green through gray-brown, named for its tail plate: smooth and evenly domed where related species carry raised ridges and knobs. That plate is not decoration - a mantis shrimp holding a burrow blocks the entrance with it and takes hits on the armour, and rival males settle disputes by taking turns striking each other's tails rather than fighting to injury, one of the few ritualised contests known in crustaceans.
It lives in cavities inside dead coral heads from the shallows to about 15 m (50 ft), enlarging a hole to fit and defending it against anything that comes close. Hunting happens by day, in short excursions within a body length or two of the entrance; the diet is snails, hermit crabs and small bivalves, opened with clubs that accelerate as fast as a bullet leaving a small-calibre barrel. Color is not a reliable way to name mantis shrimps, so the smooth tail is the character to photograph if you want the identification confirmed later.
- smooth tail plate without prominent ridges
- green to gray-brown body, often with paler legs
- heavy club-shaped smashing claws
- length up to 10 cm
