OegopsidaRichard E. Young and Michael Vecchione
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.
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.close box
Among cephalopods, oegopsid squids dominate the pelagic, oceanic environment. Diversity at the family and generic levels is very high with 24 families and 69 genera. Although pelagic, some species are consistently associated with and some occasionally sit on the ocean floor.
- without cornea covering eyes.
- with a gladius.
- Suckers without circularis muscles.
- Tentacular club usually with carpal (= proximal) locking-apparatus.
- Suckers without circularis muscles (see Sepioidea page).
- Buccal crown
- Buccal supports lack suckers.
- Head without tentacle pockets.
- Eyes without corneal membranes covering lenses. image info
Figure. Dorsal view of the head of Pyroteuthis addolux with the protruding eye lenses directly exposed to sea water. Photograph by R. Young.
- Funnel without lateral adductor muscles.
- Mantle locking-apparatus, with rare exceptions, reaches anterior mantle margin.
- Fins usually joined posteriorly and usually without posterior lobes. image info
Figure. Ventral view of mantle and fins of Ancistroteuthis lichtensteini, 175 mm ML, Mar-Eco cruise, R/V G. O. SARS, North Atlantic. Photograph by R. Young.
- Shell a gladius.
- Gills with branchial canal. image info
Figure. Diagramatic cross-section through gills. Drawing modified from Naef (1921-23).
- Oviducts paired.
- Females without accessory nidamental glands.
- Eggs in pelagic egg masses.
Figure. Oral view of the club base of Cycloteuthis serventyi. The red line encircles the suckers and knobs of the carpal locking-apparatus. Drawing modified from Young and Roper (1969).
CommentsComparisons of the major groups of the Oegopsida
|Buccal connective to arms IV||Funnel locking-cartilage||Carpal locking-apparatus||Gladius conus||Anterior fin attachment|
|Chiroteuthid families||Ventral||Variable, usually oval, often with knobs||No||2° conus||Gladius|
|Cranchiidae||Ventral||Fused||Yes||2° conus /No||Gladius/Mantle|
|Cycloteuthidae||Ventral||Triangular||Yes||2° conus /No||Gladius|
|Enoploteuthid families||Dorsal||Straight||Yes||1° conus||Gladius|
|Lepidoteuthidae families||Ventral||Straight||No||2° conus||Gladius|
|Ommastrephidae||Dorsal||Inverted T||Yes/No||1° conus||Gladius|
Richard E. Young
Dept of Oceanography
University of Hawaii
Honolulu, Hawaii 96822
National Marine Fisheries Service
National Museum of Natural History
Washington, D. C. 20560
Page copyright © 2004 Richard E. Young and
- First online 18 August 2004
Citing this page:
Young, Richard E. and Vecchione, Michael. 2004. Oegopsida http://tolweb.org/Oegopsida/19407/2004.08.18 in The Tree of Life Web Project, http://tolweb.org/. Version 18 August 2004 (under construction).