description Spirula spirula Overview
Spirula spirula is a species of deep-water squid and the sole extant member of the order Spirulida. It possesses a distinctive internal shell coiled in a planispiral form resembling a ram's horn; these lightweight shells commonly wash ashore on tropical and subtropical beaches worldwide, though living animals are rarely observed. The species inhabits mesopelagic waters, generally between 500 and 1,000 meters in depth during the day, and migrates upward at night. Carl Linnaeus first classified the species in his 1758 Systema Naturae.
Adults are small, with mantle lengths of approximately 4 to 5 centimeters.
help Spirula spirula FAQ
Why does Spirula spirula have a coiled shell inside its body?
Its lightweight chambered shell functions as a buoyancy system, somewhat like the shell of a nautilus but enclosed inside the mantle. The tight coil gives the animal its common name, the ram's horn squid.
Why are Spirula shells common on beaches when living animals are rarely seen?
The durable internal shells float after the squid dies and can travel long distances before washing ashore. Living Spirula spirula normally occupies deep open water, commonly around 500 to 1,000 meters down during daylight.
Does Spirula spirula produce light?
Yes. It has a photophore between the small fins at the rear of its mantle that can emit a pale greenish light, which is why it is also called the tail-light squid.
Did Carl Linnaeus originally give Spirula spirula its current name?
Linnaeus described it as Nautilus spirula in the 1758 edition of Systema Naturae. Lamarck established the genus Spirula later, and the species is now written Spirula spirula.
explore Explore More
Reviews & Comments
Write a Review
Be the first to review
Share your thoughts with the community and help others make better decisions.
