Cephalopod Eyelid Sinus

Richard E. Young, Michael Vecchione, and Katharina M. Mangold (1922-2003)

Cephalopoda Glossary


The top large photograph is the head of a preserved squid, Sthenoteuthis oualaniensis. The white arrow points to the eyelid sinus. The insert photograph is an enlargement of the eyelid sinus from the first photograph. The eyelid sinus complex appears to enable complete closure of the eyelid. This is seen in the lower picture of a live squid, Ommastrephes bartramii, which is very closely related to Sthenoteuthis oualaniensis. The photographer had just touched the eyelid of this squid and it immediately responded by closing the eyelid. Note how the eyelid closed: The posterior edge of the eyelid expanded anteriorly providing most of the closure. The dorsal and ventral margins contracted and the flap over the eyelid sinus expanded to cover the remaining, slit-like opening. Probably a circular eyelid drawn together from all sides equally would not be able to close completely but would leave an central pore exposed.

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Figure. Side views of the heads of Sthenoteuthis oualaniensis (top) and Ommastremphes bartramii (bottom). Photographs modified from: Young, R. E., M. Vecchione and D. Donovan (1998).


Young, R. E., M. Vecchione and D. Donovan. 1998. The evolution of coleoid cephalopods and their present biodiversity and ecology. South African Jour. Mar. Sci.., 20: 393-420.

About This Page

University of Hawaii, Honolulu, HI, USA

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

Katharina M. Mangold (1922-2003)
Laboratoire Arago, Banyuls-Sur-Mer, France

Page: Tree of Life Cephalopod Eyelid Sinus Authored by Richard E. Young, Michael Vecchione, and Katharina M. Mangold (1922-2003). 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.

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