Under Construction
This is an archived version of a Tree of Life page. For up-to-date information, please refer to the current version of this page.

Argonautoida Naef, 1912

Richard E. Young and Michael Vecchione
Four families comprise a well-defined monophyletic clade.
taxon links [down<--]Incirrata [up-->]Alloposidae [up-->]Tremoctopodidae [up-->]Argonautidae [up-->]Ocythoidae Interpreting the tree
close box

This tree diagram shows the relationships between several groups of organisms.

The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.

example of a tree diagram

You can click on the root to travel down the Tree of Life all the way to the root of all Life, and you can click on the names of descendent subgroups to travel up the Tree of Life all the way to individual species.

For more information on ToL tree formatting, please see Interpreting the Tree or Classification. To learn more about phylogenetic trees, please visit our Phylogenetic Biology pages.

close box
Containing group: Incirrata


All four families of the Argonautoida are pelagic although one (Alloposidae) is "associated" with the ocean floor. The families are primarily distinguished by an unusual means of copulation which involves transferring a detached hectocotylus from the male to the female. The clade includes gelatinous species as well as very muscular species.


An incirrate octopod ...


  1. Arms
    1. Arm suckers in two series (grade to single series near mouth in Haliphron).
    2. One of third arm pair entirely hectocotylized and enrolled in a sac or pouch prior to use.
    3. Hectocotylized arm autotomizes (i. e., detaches) during copulation.
       image info

      Figure. Detached hectocotylus of Argonauta argo found wiggling among contents of a midwater trawl. Photograph (overexposed) by M. Vecchione.

  2. Funnel
    1. Funnel-locking apparatus well developed but structure differs among families.
  3. Mantle
    1. Males much smaller than females; males dwarfs in three families.
  4. Shell
    1. Internal shell present only in Alloposidae; shell lost in other families.
  5. Radula
    1. Radula heteroglossan.

Discussion of Phylogenetic Relationships

Naef (1923) suggested that the argonautoid families were derived from the Octopodidae and presented a phylogeny, shown above in the title frame, based on the characteristics of the hectocotylus.

Voight (1997), in a cladistic study using mostly different characters, presented a less resolved phylogeny:

\ ------ Alloposidae
\ / ----- Argonautidae
\/ /
\/------ Ocythoidae
\----- Tremoctopodidae


Naef, A. 1921/23. Cephalopoda. Fauna und Flora des Golfes von Neapel. Monograph, no. 35.

Nesis, K. N. 1982. Abridged key to the cephalopod mollusks of the world's ocean. 385+ii pp. Light and Food Industry Publishing House, Moscow. (In Russian.). Translated into English by B. S. Levitov, ed. by L. A. Burgess (1987), Cephalopods of the world. T. F. H. Publications, Neptune City, NJ, 351pp.

Voight, J. R. 1997. Cladistic analysis of the octopods based on anatomical characters. J. Moll. Stud. 63: 311-325.

Title Illustrations
Scientific Name Argonauta nodosa, Haliphron atlanticus, Ocythoe tuberculata, Tremoctopus violaceus
Acknowledgements courtesy of Mark Norman
Copyright © 1996 David Paul (Argonauta), Ron Gilmer (Haliphron), Dorothy Petersen (Ocythoe), M. Vecchione (Tremoctopus)
About This Page

Richard E. Young
University of Hawaii, Honolulu, HI, USA

National Museum of Natural History, Washington, D. C. , USA

Citing this page:

Young, Richard E. and Vecchione, Michael. 2006. Argonautoida Naef, 1912. Version 16 July 2006 (under construction). http://tolweb.org/Argonautoida/20192/2006.07.16 in The Tree of Life Web Project, http://tolweb.org

edit this page
close box

This page is a Tree of Life Branch Page.

Each ToL branch page provides a synopsis of the characteristics of a group of organisms representing a branch of the Tree of Life. The major distinction between a branch and a leaf of the Tree of Life is that each branch can be further subdivided into descendent branches, that is, subgroups representing distinct genetic lineages.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

close box


Page Content

articles & notes




Explore Other Groups

random page

  go to the Tree of Life home page