Paper Nautilus LESSER ARGONAUT Argonaut hians The Argonauts are a truly pelagic octopus that spend their entire life at sea. tema Piemor They are found circumglobaly and in almost every ocean with the exception of the polar regions. Nicknamed "Nautilus" for the shape of their shell, they are definitely not a Nautilus. The shell is created exclusively by the female to brood her eggs. Using their 3rd and 7th arm, the female forms the shell with a calcite compound unlike any other shell formed in nature. The shell doesn't contain compartments or chambers (like a true Nautilus) to assist with buoyancy, so the female traps air in her shell at the surface by "Looping over." This trapped air assists them in maintaining a shallow position in the water column and closer to their food source of crustaceans and more importantly for meeting a mate. The male argonaut looks similar to amid-water octopus although very small. The second highest degree of sexual dimorphism in nature occurs with Argonauts with the male no larger than 20-30 mm, being the largest we've ever encountered. Most are as small as a garden pea. The Female can get quite large measuring in at 150 mm. for the male. From there the fernale does the rest of the work, fertilizing her eggs one at a time while she lays them into her protective shell. The shell is remarkable. It is hard, and often times the female will run into our camera housings, our heads and sometimes our lights. The contact makes a hard clicking thud before they spin off clumsily and begin jetting again. However, the discarded shell, when found on the substrate are extremely delicate and crumble to the touch. It is also common to see Argonauts using flotsam of all variety to assist them in remaining in the Male Argonauta hians among a Siphonophore Mating: Like other octopus, the male uses his modified 7th arm, called the hectocotylus, to transfer the sperm to the female. The male touches the female, the arm breaks off, and the act is complete Male Argonauta hians on the top of a drifting Jellyfish Male Argonauta hians on the top of a drifting Salp