General Description

Rostrum acute, 3 times as long as broad at base, separated from orbital hoods by deep short grooves overhung by base of rostrum; orbital hoods with converging acute teeth, reaching half length of rostrum; rostrum-hood margins short and convex. Large claw (chela) laterally compressed; lower margin slightly concave, irregular proximally; upper margin with longitudinal groove; without lateral and medial teeth near dactylar articulation; with only few scattered setae. Small claw (chela) not of balaeniceps form. Maxilliped 3 with penultimate article not lobed on the lower margin. Dull orange and with orange-red chelipeds. Up to 3.5 cm long.

Biology

Snapping shrimps or pistol shrimps are immediately distinguished from other families by having one claw much larger than the other, the larger claw cylindrical and with a parrot-beak-like finger. The snapping apparatus on the claw involves a piston at the base of the moveable finger that fits into a cavity of the fixed finger. When clicked closed by the strong muscles in the palm, a sudden jet of water is expelled to stun its prey, such as crabs and fishes. A sharp click is heard at the same time and may even be audible to us when walking over mudflats where the shrimps can be common.

Distribution

Southern temperate oceans, including southern Australia.

Habitat

Intertidal to 29 m depth.

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