Under Construction

Sepioteuthis Blainville, 1824

Reef squids

Michael Vecchione and Richard E. Young
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Three nominal species are present in Sepioteuthis.
taxon links [up-->]Sepioteuthis sepioidea [down<--]Loliginidae 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
Type species. -- Loligo sepioidea Blainville, 1823 by original designation.
Containing group: Loliginidae


Sepioteuthis is distinctive; unlike in many loliginid genera, controversy does not exists over which species should be included (Vecchione et al., 1998). These loliginids have a rather broad, posteriorly rounded mantle and fins that extend nearly the full length of the mantle. This gives them a Sepia-like appearance. They also lay eggs that are much larger than those of other loliginids. They usually are found in shallow tropical or subtropical regions.

Brief diagnosis:

A loliginid ...


  1. Arms
    1. Arm sucker rings with pointed teeth around entire margin.
    2. Hectocotylus:
      1. Ventral crest absent.
      2. Proximal suckers unmodified.
      3. Distal suckers reduced, sucker stalks elongated along modified portion of arm to form papillae on both dorsal and ventral rows.

  2. Tentacles
    1. Tentacular clubs expanded, with suckers in four series.

  3. Head
    1. Beaks: Descriptions can be found here: Lower beak; upper beak.
  4. Mantle
    1. Posterior mantle not elongated into tail-like structure.

  5. Fins
    1. Extend nearly full length of mantle (>85% of ML) except in very young squid.
      Click on an image to view larger version & data in a new window
      Click on an image to view larger version & data in a new window

      Figure. Dorsal view of S. lessoniana, adult showing the large fins. Drawing from Roper, et al. (1984)

  6. Photophores
    1. Photophores absent.

  7. Viscera
    1. Eggs larger than 5 mm.
    2. Eggs lie in single, straight series within egg strand.
    3. Spermatophore cement body short.

Discussion of Phylogenetic Relationships

Relationships among species are uncertain. Segawa et al. (1993) suggest that S. lessioniana represents a species complex.


Because of their association with coral reefs, the common name for these species is "reef squids". The distribution of the genus generally follows that of coral reefs, warm, clear, tropical and subtropical waters, but coral reefs are not a habitat requirement for all of these squids. For example, S. lessoniana is common around the southern part of Honshu and Kyushu in Japan, but is not associated with coral reefs in those areas and occupies temperate waters of southern Australia. There is one species, S. australisS. sepioidea, in the western Atlantic; the remaining species are found in Indo-West Pacific waters.

Other Names for Sepioteuthis Blainville, 1824


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.

Segawa, S., S. Hirayama and T. Okutani. 1993. Is Sepioteuthis lessoniana in Okinawa a single species? Pp. 513-521. In: T. Okutani, R. K. O'Dor and T. Kubodera (eds). Recent Advances in Cephalopod Fisheries Biology. Tokai University Press, Tokyo.

Vecchione, M., T. F. Brakoniecki, Y. Natsukari and R. T. Hanlon. 1998. A provisional generic classification of the family Loliginidae. Smithson. Contr. Zool., 586

Title Illustrations
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Scientific Name Sepioteuthis sepioidea
Specimen Condition Live Specimen
View Anterodorsal
Copyright © Roger Hanlon
About This Page

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

University of Hawaii, Honolulu, HI, USA

Correspondence regarding this page should be directed to Michael Vecchione at

Page: Tree of Life Sepioteuthis Blainville, 1824. Reef squids. Authored by Michael Vecchione and Richard E. Young. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Vecchione, Michael and Richard E. Young. 2010. Sepioteuthis Blainville, 1824. Reef squids. Version 02 September 2010 (under construction). http://tolweb.org/Sepioteuthis/19862/2010.09.02 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