Spirula spirula is a species of deep-water squid-like cephalopod mollusk. It is the only extant member of the genus Spirula, the family Spirulidae, and the order Spirulida. Because of the shape of its internal shell, it is commonly known as the ram's horn squid [3] or the little post horn squid.

Coleoids, a shell-less subclass of cephalopods (squid, cuttlefish, and octopuses), have complex pigment containing cells called chromatophores which are capable of producing rapidly changing color patterns.

While most squid have a flattened shell remnant called a pen, the ram's horn squid has an internal coiled shell that they use to control buoyancy like the nautilus. (Ewald Rübsamen from Die Cephalopoden)

May 16, 2022 · The squid is also known as the little post horn squid, or—as it has a light-emitting organ on one end—the tail-light squid. The ram’s horn squid uses its tightly coiled shell as a buoyancy organ to travel up and down through the tropical …

Apr 24, 2018 · Ancient squid used to have shells, but modern squid no longer do. How have cephalopods’ shells evolved from a form of armor to means of transportation? How have they adapted to further suit these animals’ needs?

Cuttlefish (sometimes called "cuttles") look like squid, but have stouter bodies with a broad internal shell called a cuttlebone or sepion. They move mostly by undulating their body fins and can live in the water column or at the sediment surface.

Oct 28, 2020 · The ram's horn squid is rarely seen in the wild, and it's one of the most unusual cephalopods out there. Apart from cuttlefish, it's the only other known mollusc that contains an internal chambered shell to keep it buoyant.

The ram's horn squids spend most of their lives in a heads down position. The gas-filled internal shell keeps the posterior end up. These squids also have a light-emitting organ between the 2 posterior fins (hence, the name tail light squid).

Jun 20, 2017 · A special squid. There is one “squid” called Spirula spirula, or the ram’s horn squid, which also has an internal, loosely coiled shell with septa; hardly anyone knows about it because it lives in the deep sea. Sometimes after a ram’s horn …

They are a short, cylindrical squid that is easily recognised by their coiled internal shell, light organ and fins on the end of the body. Their luminescent skin is a dark reddish brown, however this colouring is often lost in trawled animals.