Paper Nautilus, Argonaut
Argonauta Común, Pulpo
(Argonauta nouryi)

Identification Photos: Paper Nautilus, Argonauta nouryi: This cephalopod is one of the most interesting and exotic species from the sea. It has a pelagic existence traveling the globe in free ocean water away from the bottom and near the surface and is a resident of all tropical and subtropical oceans.

The Paper Nautilus is 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. It has eight tentacles, two of which are unique, and web-like, used to collect food. In addition, the Paper Nautilus is not a nautilus but is a member of the order Octopoda (which includes the octopuses) and the family Argonautidae. Argonauta shells are washed ashore globally, but the collection of an animal still resident in its shell is a very rare event.

The female Paper Nautilus reaches a size of four inches and can generate a shell that can reach up to sixteen inches. The maximum size of the male is about one-third that size. 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 scientific name of the Paper Nautilus, Argonauta, is of mythical Greek origin. The Argonauts were a group of Greek heroes that, led by Jason, 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 as an aid to locomotion, and thus its similarity to the mythical Argo.

Cephalopods are of great interest to the scientific community since they are believed to have appeared during the late Cambrian Period, more than 400 million years before the first primitive fish began swimming in the ocean. This was 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 believed to be in existence.

Paper Nautilus, Argonauta nouryi: Collected on shore in its own shell (pictured above) with a brood of one zillion eggs early morning in 70-degree water, in April 2004, in the surf line by hand at Km. 20 (Cabo Real) between Cabo San Lucas and San Jose del Cabo, Baja California Sur, Mexico. Overall size 4 inches, with the shell just under 2 inches. This species is one of eight Argonautas. It is easily confused with the pelagic Argonauta argo, and one of the rarest, found only in a limited area off Western Mexico. Rumor has it that most conchologists would KILL to obtain one! 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 were empty. Description and photos courtesy John Snow. Identification courtesy Mietek Golos, London.

 

A Paper Nautilus Primer

By Mietek Golos

Most of the known species of Argonauta can be found in Mexican waters, but most notably, the three (probably) rarest species: Argonauta cornuta, Argonauta nouryi, and Argonauta pacifica (which are also seemingly endemic to this region). As Argonauta argo and Argonauta hians are present in most tropical and subtropical waters around the world these are probably present in the region as well. I am not knowledgeable about Argonauta nodosa's distribution though.

Out of the eight recognised species, I am most sketchy on Argonauta pacifica as there is close to no information available on it (and is also the only species missing in my collection).

For the other seven, I will attach photos as I believe that the pictures will give a better idea of how to distinguish them.

Photo 1: The first photo is of Argonauta hians "No. 1" which seems to be a very common type. Shells of this Argonaut are usually cream or light sepia in colour and are quite compact. The shell's surface is very smooth with ribs which are barely visible. The tubercles (knobs on top of the shell) are very small and rounded. I have found that shells of this type of Argonauta hians usually don't get very large. Most specimens which I have seen are below 6 cm in size and I have never seen any over 9 cm. Most representatives of this form seem to come from the Philippines. Photo courtesy Mietek Golos.

Photo 2: The second photo is of Argonauta hians "No. 2" which is uncommon. This type seems to grow much larger; I have seen numerous specimens past 10 cm (I myself have a shell of 122 mm). The shells of this variant of Argonauta hians usually have a much darker colour (dark brown to even black) and display much more prominent tubercles and ribbing. They also display large "spikes" protruding from both sides of the shell. Argonauta hians "No. 2" seems to be most abundant in the waters surrounding Taiwan and Japan. Photo courtesy Mietek Golos.

Photo 3: The third photo displays a specimen of Argonauta boettgeri, a species often confused with Argonauta hians. These shells seem to be the smallest of all the paper nautiluses (the WRS is listed at a mere 61.9 mm). Argonauta boettgeri originates from Southern Africa (especially Mozambique, where most specimens are from). These are rare finds and vary wildly in degree of pigmentation, but most seem to be of a dark color (brown/black). Another characteristic of this species is that the shells are usually finely granulated and display very prominent tubercles and well developed ribs (which are usually "wavy"), which alternate in length (one long, one short, etc.). Photo courtesy Mietek Golos.

Photo 4: Photo number 4 is of the rare Argonauta nouryi. The shell pictured is 87.3 mm in length (I have another specimen measuring 94 mm), which is at the higher end of their size range. This is one of the rarest Argonauta species and can only be found in the waters around Mexico and Baja California. If my memory serves me well then there have only been two known strandings of this species (both my shells came from the 1992 stranding). The shells of this species are hard to confuse with those of any other, being probably the most elongate of any paper nautilus. The shells are of a white or cream colour (with the oldest tubercles having a brownish pigmentation) and possess numerous small knobs on the keel. The surface of the shell is very smooth and has a large number of underdeveloped ribs. The photo that of the paper nautilus that Dr. John Snow provided seems to be a small example of this species. Photo courtesy Mietek Golos.

Photo 5: The fifth photo shows what I believe to be Argonauta cornuta, though I am not sure as the limited amount of photographic material available regarding this species, seems to be conflicting. Photo courtesy Mietek Golos.

Photos 6 and 7: Photos 6 and 7 are of Argonauta argo and Argonauta nodosa respectively. These are the two largest species and cannot be confused with any others. Photos courtesy Mietek Golos.

Photo 8: The final picture shows an Argonauta cygnus which produces a very elongate and smooth shell, which can be easily distinguished from Argonauta argo by the presence of Argonauta argo-like pointy extensions on the keel. (Picture courtesy of Guido Poppe, from whom I purchased this specimen.)


As mentioned before, I do not have Argonauta pacifica and I am not sure exactly what it is supposed to look like. From the limited information that is available, I can say that it grows to a shell size of at least 220 mm and is present in Mexican waters. The only photo of it that I am aware of can be found here:

http://shell.kwansei.ac.jp/~shell/pic_book/data26/r002593.html

--Mietek Golos