Argonauta hians (3) mm 59 Seashell Sea Snail Cephalopod Octopus Paper Nautilus

Argonauta hians mm 59 Seashell Sea Snail Cephalopod Octopus Paper Nautilus, female Parchment Shell, only a piece, as in photos.
Attention: the specimen has a damage due to a fracture on the last spire, which has been restored, as shown in the photos.
Family: Argonautidae.
Common name: Winged Argonaut, Muddy Argonaut, Grey Sea-Horse's Nest or Brown Paper Nautilus.
Syn. Argonauta gondola, Argonauta haustrum, Ocythoe cranchii, Argonauta nitida, Argonauta crassicosta, Argonauta raricosta, Octopus (Philonexis) minimus, Argonauta owenii, Argonauta kochiana, Argonauta cornuta, Argonauta dispar, Argonauta polita, Argonauta expansa.

Argonauta hians a species of pelagic octopus. The female of the species, like all Argonauts, creates a very thin egg cup that wraps around the octopus just like a nautilus lives in her shell. This calcareous ootheca is characterized by a wide keel which gives it a square appearance, a few rounded tubercles along the keel and fewer than 40 smooth ribs on the sides of the shell.

The genus Nautilus and Argonauta, cephalopods tetrabranchiata (in contrast to cuttlefish, octopus and squid that are dibranchiata) are the last descendants of the Ammonites, that large group of molluscs with a spiral shell that populated the prehistoric seas millions of years ago. From Belemnites, on the contrary, are derived the dibranchiata on cited, having incorporated the outer shell just inside the body (the cuttle bone is the remains).