Paper Nautilus

Paper Nautilus, Argonauta nouryi

The Paper Nautilus, Argonauta nouryi, which in Spanish is known as Argonauta Común is a cephalopod of the family Argonautidae.  The Paper Nautilus is not a nautilus but is a member of the order Octopoda, which includes the octopuses. They are one of the most interesting and exotic species from the sea. Cephalopods are of great interest to the scientific community as are believed to have appeared during the late Cambrian Period, more than 400 million years, which was before the first primitive fish began swimming in the ocean. It was also before the first mammals appeared, before vertebrates invaded the land, and before there were upright plants on land. Cephalopods were once the dominant life form of the world’s oceans and at present 650 living species are known.

The Paper Nautilus is one of eight species of known Argonautas and is one of the rarest, found only in a limited area off Western Mexico. It has a pelagic existence traveling near the surface in free ocean water away  in both tropical and subtropical oceans. They are named for the shell of the female, generated for protection of her eggs, but it is not made of paper. The female Argonauta lives in the shell, protecting the eggs from predator attack until they hatch. Argonauta shells are washed ashore globally, but the collection of an animal still in residence in its shell is a very rare event.

The scientific name of the Paper Nautilus, Argonauta, is of mythical Greek origin. The Argonauts were a group of Greek heroes, led by Jason, that traveled to Kolchis to gain the golden fleece. The ship they traveled in was named the Argo. In Greek, Argonaut means “who travels on the Argo.” The sail-like flap of the Paper Nautilus was mistaken by its discoverers to be an aid to locomotion, and thus its connection to the mythical Argo. Rumor has it that most conchologists would KILL to obtain an Argonauta shell!

The Paper Nautilus has eight tentacles, two of which are unique, and web-like, used to collect food.  The female Paper Nautilus reaches  10 cm (3.9 inches) in length and can generate a shell that can reach 40 cm (16 inches). The maximum size of the male is about one-third the size of the female. The male can be differentiated from the female by the existence of an altered third tentacle (the hectocotylus) that it keeps in a pouch until it is needed for reproduction. Following fertilization the males die. The Paper Nautilus can be easily confused with the Greater Argonauta, Argonauta argo.

Paper Nautilus, Argonauta nouryiCollected on the beach in its own shell (pictured above) with a brood of one zillion eggs, just above the surf line at Km 21, Cabo Real, Baja California Sur, April 2004. Octopus Size: 10 cm (3.9 inches); shell 4.2 cm (1.7 inches) x 2.8 cm (1.1 inches). Identification courtesy Mietek Golos, London. Note: in collection of this species, I was fooled badly, originally believing that a standard octopus had taken up residence in a discarded shell. Only when I removed the “octopus” from the shell did I discover the brood of eggs. An excellent photo opportunity was lost! I also collected two additional Paper Nautilus shells adjacent to this collection, but both shells were empty.

Paper Nautilus, Argonauta nouryi. Collected off the beach in Los Barriles, Baja California Sur, December 2017. Larger shell size: 12.2 cm (4.8 inches) x 8.1 cm (3.2 inches).  Collection courtesy of Mike Rousseau, Maple Ridge, British Columbia, Canada. First two photos courtesy of Brad Murakami, Surrey, British Columbia, Canada.