Pistol shrimp
| Alpheidae | |
|---|---|
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| Alpheus digitalis | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Infraorder: | Caridea |
| Superfamily: | Alpheoidea |
| Family: |
Alpheidae Rafinesque, 1815 |
| Genera | |
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Alpheidae is a family of caridean snapping shrimp characterized by having asymmetrical claws, the larger of which is typically capable of producing a loud snapping sound. Other common names for animals in the group are pistol shrimp or alpheid shrimp.
The family is diverse and worldwide in distribution, consisting of about 1119 species within 38 or more genera. The two most prominent genera are Alpheus and Synalpheus, with species numbering well over 250 and 100, respectively. Most snapping shrimp dig burrows and are common inhabitants of coral reefs, submerged seagrass flats, and oyster reefs. While most genera and species are found in tropical and temperate coastal and marine waters, Betaeus inhabits cold seas and Potamalpheops is found only in freshwater caves.
When in colonies, the snapping shrimp can interfere with sonar and underwater communication. The shrimp are a major source of noise in the ocean.
The snapping shrimp grows to only 3–5 cm (1.2–2.0 in) long. It is distinctive for its remarkably disproportionate large claw, larger than half the shrimp's body. The claw can be on either arm of the body, and unlike most shrimp claws does not have typical pincers at the end. Rather, it has a pistol-like feature made of two parts. A joint allows the "hammer" part to move backward into a right-angled position. When released, it snaps into the other part of the claw, emitting an enormously powerful wave of bubbles capable of stunning larger fish and breaking small glass jars.
Some pistol shrimp species share burrows with goby fishes in a symbiotic relationship. The burrow is built and tended by the pistol shrimp, and the goby provides protection by watching out for danger. When both are out of the burrow, the shrimp maintains contact with the goby using its antennae. The goby, having the better vision, alerts the shrimp of danger using a characteristic tail movement, and then both retreat into the safety of the shared burrow. So far this association has been observed in species that inhabit coral reef habitats.
Eusocial behavior has been discovered in the genus Synalpheus. The species Synalpheus regalis lives inside sponges in colonies that can number over 300 members. All of them are the offspring of a single large female, the queen, and possibly a single male. The offspring are divided into workers who care for the young and predominantly male soldiers who protect the colony with their huge claws.
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Wikipedia