Diversity of Squid
The giant squid may be the biggest, but it’s not the only squid in the sea. Scientists estimate there are about 500 species of squid. Some are surprisingly tiny—only about 2.5 cm (1 in) in length. Others are impressively large. There are three species of giant squid (Architeuthis), the largest of which may grow up to 16 m (50 ft) long. And there are other large squid as well—including one known as the colossal squid (Mesonychoteuthis hamiltoni). Despite these vast differences in size, all squids share certain features: long, cylindrical bodies, usually with eight arms and two long feeding tentacles; and two fins that help them balance and maneuver as they swim.
(image: Kim Moeller/Smithsonian Institution)
An illustration of Dana Octopus Squid, Taningia danae. The species is one of the larger bioluminescent squids, reaching up to 2.3 m in total length. It has been observed to emit blinding flashes of light from a pair of photophores on its arms in order to disorientate its prey.
Art by Chris Barela.
While we’re at it, here’s a cute mugshot of a piglet squid, Helicocranchia pfefferi.
Also a deep sea dweller - mesopelagic to be specific.