Southern Dumpling Squid (Euprymna tasmanica)

The southern dumpling squid is a type of bobtail squid, which comprises a group of cephalopods that are closely related to cuttlefish. Though they are able to change colour, similar to a cuttlefish, they are often iridescent green and yellow with brown spots covering their body. These little squid can be found in the shallow coastal waters of the Great Southern Reef in seagrass beds or sandy areas near reefs. They will burrow themselves into the seafloor during the day, using their second pair of arms to rake sand over the top of their body as a form of protection. The upper surface of their skin is highly specialised and contains two special cell types. One acts like glue to hold the sand in place even if they are flushed out of the seabed by a potential predator. The other contains special acid cells that allow the sand coat to disconnect all at once — leaving it as a sinking decoy while the squid jets away. Being nocturnal creatures, the southern dumpling squid emerge at night to forage for crustaceans and fish. Like other bobtail squid, they have a butterfly-shaped light organ situated on their mantle cavity filled with symbiotic bioluminescent bacteria. These bacteria are fed sugars by the squid in return for making light. The organ contains filters which may alter the wavelength of luminescence closer to that of downwelling moonlight and starlight, thus allowing the squid to cancel its silhouette and remain undetected as it swims above upward-looking predators.