Thursday, March 26, 2009

Mantis Shrimp, Squilla empusa


Well, beach walking has caused me to start researching again. Seems that I must be fond of finding weird crustaceans. Besides the barnacle, I ran across a Mantis Shrimp. It’s not a shrimp at all, but is in the crustacean class: Malacostraca. It has it’s own Superorder, Hoplocarida and a single order: Stomatopoda and Family: Squillidae. The one I found has a latin name of Squilla empusa. Spotted at dusk on Ocean Isle Beach, NC, it was just wiggling near it’s burrow. The Mantis Shrimp got it’s name from the fact that it looks like a cross between a preying mantis and a shrimp, but is neither.

When I started reading about it I found a large contingent of aficionados on the internet. It seems there are a lot of people who keep them in salt water tanks while others find them to be pests that have sneaked into their tanks in live coral. There are two different types, ones that spear their prey and ones that club their prey. The one seen here spears its prey. The ones that club their prey have been known to even break a fish tank.

There are 8 pairs of appendages. The first two are hairy and thin and used for cleaning. The second two are very large and shaped like scythes and are used to stab their prey (or your finger if you try to pick it up). The third through the fifth set are small legs that end in a flat oval shape called chelone. The chelone is used to bring food into the mouth. The last three pairs are long and thin and are used as walking legs. The sharp scythe-like appendage has 6 spines found at the last joint (Hickman 1973). Their strike is one of the fastest movements known in the animal kingdom, taking less then 8 milliseconds to strike, which is about 50 times faster than the blink of an eye (Squatriglia 2001; San Juan 1998, DBW 1998). These claws are strong enough to dig through sand, rocks and even lacerate a hand, which is why they are also known as "thumb splitters", "finger poppers", "killer shrimp" and "thumb busters" (San Juan 1998, DBW 1998, CIMS 2000).They live in sand burrows with many openings and can be found in off shore water up to 150 meters. The Squilla.empusa is a nocturnal carnivore that feeds mainly on soft bodied animals like fish, shrimps, krill, marine worms, snails and other mantis shrimp (CIMS 2000).