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Sepioidea Naef, 1916

Michael Vecchione and Richard E. Young
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taxon links [up-->]Sepiidae [up-->]Sepiolida [down<--]Decapodiformes Interpreting the tree
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Containing group: Decapodiformes

Introduction

We place three families in the sepioid clade: Sepiidae, Sepiadariidae and Sepiolidae. The latter two families are related and placed in the suborder Sepiolida. Two additional families (Idiosepiidae, Spirulidae) have often been included in the Order Sepioidea. However considerable uncertainty exists concerning the relationships of the Idiospiidae in general and the closeness of the relationship of the Spirulidae to the sepioid families. Members of the sepioidea are mostly neritic and upper slope benthic species although one group (Heteroteuthinae) is pelagic.

Brief diagnosis:

A decapodiform ...

Characteristics

  1. Arms
    1. Suckers with circularis muscles.

  2. Tentacles
    1. Tentacular club without proximal (= carpal) locking-apparatus.
    2. Suckers in more than four series (except in some Sepiolidae).
    3. Suckers with circularis muscles.
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      Click on an image to view larger version & data in a new window

      Figure. Sections through the club suckers. Left - Sepia officinalis, arrow points to circularis muscle which encircles the sucker. Middle - Ommastrephes bartramii. Note absence of a circularis muscle. Right - Sepia officinalis, section at right angles to left figure, circularis muscle in blue; the asymmetry in the muscle is revealed by the angle of section. Histological sections made by Barbara Littman; photographed by R. Young. Drawing modified from Naef (1921-23).

  3. Buccal crown
    1. Buccal supports with or without suckers.

  4. Head
    1. Head with tentacle pocket.
    2. Eyes with corneal membranes covering lenses.
    3. Eyes with secondary (= ventral) eyelid (except in some Sepiolidae).
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      Click on an image to view larger version & data in a new window

      Figure. Lateral view of head of Rossia sp., 19 mm ML, preserved, showing secondary eyelid covering the ventral region of the transparent cornea. Photograph by R. Young.

  5. Funnel
    1. Funnel with lateral adductor muscles (except in some Sepiolidae).
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      Click on an image to view larger version & data in a new window

      Figure. Ventral view of mantle cavity of Semirossia tenera (Sepiolidae). Photograph by M. Vecchione.

  6. Mantle
    1. Mantle locking-apparatus does not reach anterior mantle margin (see short arrow in above photograph which marks the anterior end of the mantle locking-apparatus) except in some Sepiolidae.
    2. Interstellate connective absent (ie, no direct nerve connective passes directly from one stellate ganglion to the other).

  7. Fins
    1. Fins completely separate from one another; usually with posterior lobes.

  8. Shell
    1. Shell a flattened phragmocone (=cuttlebone), a gladius or absent.

  9. Viscera
    1. Gills without branchial canal.
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      Click on an image to view larger version & data in a new window

      Figure. Diagramatic cross-section through gills. Drawing modified from Naef (1921-23).

    2. Right oviduct absent.
    3. Females with accessory nidamental glands.

  10. Eggs
    1. Eggs, where known, attached to substrate singly or in unorganized groups.

Synapomorphies

Many of the above characteristics of the Sepioidea are shared with the Myopsida. The characters that unite the Sepiidae and the Sepiolida and are considered to be apomorphic (newly derived) characters are (characters 3 and 5 seem to be independently derived in a few Myopsida):

  1. Eyes with secondary eyelids.
  2. Funnel with lateral adductor muscles.
  3. Mantle locking-apparatus that does not reach the mantle margin.
  4. Absence of an interstellate connective.
  5. Gills without a branchial canal
Title Illustrations
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Click on an image to view larger version & data in a new window
Scientific Name Sepioloidea lineolata, Sepia apama, Iridoteuthis iris
Copyright © 2004 Mark Norman, Thomas burch
About This Page


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


University of Hawaii, Honolulu, HI, USA

Page: Tree of Life Sepioidea Naef, 1916. 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. 2008. Sepioidea Naef, 1916. Version 21 April 2008 (under construction). http://tolweb.org/Sepioidea/23870/2008.04.21 in The Tree of Life Web Project, http://tolweb.org/

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