Ryan Photographic - Alpheidae - Snapping shrimp
Snapping shrimp, also known as pistol shrimp, are renowned for having one claw much larger than the other. Basically this big claw is both a hammer and an anvil. The hammer is locked into position and when released, produces a powerful shock wave (in fact, depending on how it is measured, some pistol shrimps are the loudest creatures on the planet). As is discussed in the mantis shrimp family Odontodactylidae, the force of the release produces a cavitation bubble and this may be sufficient to stun or kill small prey.
There are around 670 species of alpheids distributed in ten genera. As a family they are full of surprises. Seven species exhibit eusociality, a community structure characterised by a division of labor, overlapping generations and both reproductive and non-reproductive castes. The first species to be recognized with this behavior, Synalpheus regalis, lives its entire life inside sponges. The only reproductive individual, the queen, rules a colony of up to 300 members. For more information about this species check out the Wikipedia entry.
Another synalpheid was described in 2017. In a lovely touch of whimsy, based on its enlarged pink claw, the authors called it Synalpheus pinkfloydi. They determined that the noise produced by the claw reached 210 decibels.
Snapping shrimp were the bane of hydrophone operators trying to detect submarines during the Second World War. There is a great discussion of this history and how the shrimp produce the noise here.
Several dozen snapping shrimp species have a commensal arrangement with gobies (small, bottom dwelling fish). The shrimp build and maintain a burrow. In return, the goby acts as a "watch goby" (don't you have one?). The shrimp, lacking good vision, maintains contact with the goby with one of its long antennae. If the shrimp detects a threat, they both bolt down the burrow.
Several snapping shrimp species live on featherstars and typically match their hosts coloring quite closely. I have photos of several of these below.
A big thank you to my friends on Scuba Diving Friends who helped me with several of these identifications.
Alpheid shrimp goby
Alpheid goby prawn Raja Ampat West Papua IMG_0397
Alpheus bellulus Tiger pistol shrimp
Alpheus bellulus Tiger pistol shrimp with Cryptocentrus cinctus Banded shrimp goby (yellow morph) Raja Ampat IMG_1507
Alpheus bellulus tiger snapping shrimp with Cryptocentrus cinctus Banded shrimp goby Raja Ampat West Papua IMG_0426
Alpheus bellulus tiger snapping shrimp with Amblyeleotris steinitzi. Puerto Galera, Philippines. IMG_5164
Alpheus novaezelandiae, Snapping shrimp
Alpheus novaezelandiae, Snapping shrimp, Somes Island, New Zealand IMG_0073
Alpheus ochrostriatus, Fine-striped snapping shrimp
Alpheus ochrostriatus, Fine-striped snapping shrimp, Raja Ampat IMG_3026
Synalpheus stimpsoni Stimpson's snapping shrimp
Synalpheus stimpsoni Stimpsons snapping shrimp
Synalpheus stimpsoni, Stimpson's snapping shrimp, Magic Bay Rao, Morotai, Indonesia 5P7A6806
Unidentified snapping shrimp
Unidentified snapping shrimp with Ctenogobiops mitodes? shrimp goby, Taveuni IMG_0143