Our creature of interest in this one-minute episode of visual meditation goes by many names: squat shrimp, Thor amboinensis, anemone shrimp, dancing shrimp, sexy shrimp, just to name a few.
Take a look at a squat shrimp (Thor amboinensis)
Thor ambionensis has a maximum body length of 13 millimetres. Their base body colour varies from red/orange to light brown, and even green. They have irregular blue/white circular marks on the body. In the centre of these marks, there are yellow lines and dots. On the brown coloured specimens, the colours in the centre of these marks are slightly different. There are two or sometimes three similar coloured bands around the tail area and the tail fan has similar coloured markings on the top and the bottom. There are three sets of walking legs and a set of legs with small pincers known as chelipeds and a proportionally longer set of feelers.
They like to move it, move it
They have a habit of holding their abdomen above their head and wagging the tail giving them one of their common names. Though it is named after Ambon, or Amboyna Island, one of the Maluku Islands in Indonesia, Thor amboinensis has a pantropical distribution and can be found in the Red Sea, the Indian Ocean, the Pacific Ocean, the Caribbean Sea, the Gulf of Mexico, and even at the Atlantic islands of Madeira and the Canaries.
Living together: Thor amboinensis and anemones
They prefer to live in a symbiotic relationship with anemones, but when none are around, can also be found in certain species of corals. Living among the tentacles of their preferred host, the voracious anemone offers them a safe home from which they can feed on tentacle tissue, as well as on the mucus-trapped planktonic particles adhering to it.
Squat shrimps: The next generation
The female Thor amboinensis carries the fertilised eggs under her abdomen until they are ready to hatch. The zoea larvae pass through several stages and, before undergoing a metamorphosis, are attracted by both chemical and visual cues which cause them to settle near potential host anemones. Researchers found that the larvae of Thor amboinensis were generalists, being attracted by and accepting several different species of anemone as hosts. In some experiments, they had a preference for the species of anemone from which the parent shrimp had been collected.
It’s always fun to spend some time with these little fellows and watch them dance around, shaking that booty.