Mastigoteuthis magna group
Richard E. Young and Michael VecchioneIntroduction
M. magna-group is very distinctive and its members cannot be easily confused with any other Mastigoteuthis. Squid in this group can be relatively common in warm temperate to tropical waters. One form is known only from Subantarctic waters.
Brief diagnosis:
A Mastigoteuthis with ...
- flask-shaped funnel locking-apparatus.
- very small (0.05 mm) tentacular club suckers.
Characteristics
- Arms
- Largest arm suckers in mid-arm rather than at or near arm base.
- Largest arm suckers in mid-arm rather than at or near arm base.
- Tentacles
- Tentacular club suckers of uniform size throughout
- Tentacular club suckers extremely small, ca. 0.05 mm in diameter.
- Tentacular club suckers of uniform size throughout
- Head
- Funnel pocket absent.
- Funnel
- Funnel with flask-shaped locking-apparatus.
- Fins
- Fin length usually 55-65% of ML.
- Fin length usually 55-65% of ML.
- Tubercules
- Tubercules absent from the integument.
- Tubercules absent from the integument.
- Photophores and pigmentation
- Integumental photophores absent or microscopic in size (ca. one third diameter of integumental photophores of other members of the family - see Mastigoteuthis sp. A).
- Pigment mostly in densely spaced chromatophores (possible exception in Mastigoteuthis type beta).
Click on an image to view larger version & data in a new window
Figure. Frontal view of the skin of M. magna, under high magnification. Photograph by M. Vecchione.
- Integumental photophores absent or microscopic in size (ca. one third diameter of integumental photophores of other members of the family - see Mastigoteuthis sp. A).
Comparison of "species"
Here we compare the structure of the arm suckers (club suckers are similar in all forms), the funnel locking-apparatus, photophores and pigmentation of the three forms. Other differences exist (eg, beaks) but these most apparent ones.
- Arm suckers: M. magna suckers have smooth inner rings although a hint of teeth can sometimes be seen in parallel lines on the ring. Mastigoteuthis "type beta" has small distinct teeth on the distal margin of the inner ring while Mastigoteuthis sp. A generally has a few broad, rounded teeth, fused together over most of their lengths.
- Funnel locking-apparatus: M. magna has a straight, anterior groove and a broad, posterior cup. Mastigoteuthis "type beta" has a broad groove that flares posteriorly and a rather elongate, posterior cup. Mastigoteuthis sp. A has a slender a slender, anterior groove and a rather elongate, posterior cup. These features are often easier to recognize, in reverse, that is in the mantle component of the locking-apparatus.
- Photophores: Photophores are known only in Mastigoteuthis sp. A.
- Pigmentation: Pigmentation is poorly understood except in M. magna which is covered with a dense array of red chromatophores. Mastigoteuthis "type beta" appears to be lightly pigmented and may lack chromatophores. Mastigoteuthis sp. A is pigmented similar to M. magna but pigment may not be as dense in young individuals of Mastigoteuthis sp. A.
![Click on an image to view larger version & data in a new window](http://tolweb.org/tolarchive/65303/20071119/tree/img/magnify.gif)
![](http://tolweb.org/tolarchive/65303/20071119/tree/ToLimages/MMagGroupArmSuck.jpg)
Figure. Oral or oral-oblique views of large arm suckers of members of the M. magna-group. Left - M. magna, North Atlantic. Middle - Mastigoteuthis "type beta", Subantarctic Pacific. Right - Mastigoteuthis sp. A, Hawaiian waters, central N. Pacific. Photographs by R. Young.
![Click on an image to view larger version & data in a new window](http://tolweb.org/tolarchive/65303/20071119/tree/img/magnify.gif)
![](http://tolweb.org/tolarchive/65303/20071119/tree/ToLimages/MMagGroupManLoc.jpg)
Figure. Frontal views of the mantle components of the funnel locking apparatuses in the members of the M. magna-group. Left - M. magna, North Atlantic. Middle - Mastigoteuthis "type beta", Subantarctic Pacific. Right - Mastigoteuthis sp. A, Hawaiian waters, central N. Pacific. Photographs by R. Young.
Comments
The specific status of Mastigoteuthis "type beta" is uncertain since only one individual is known and its pigmentation, its most distinctive feature, is uncertain due to some damage during capture.
About This Page
Richard E. Young
University of Hawaii, Honolulu, HI, USA
National Museum of Natural History, Washington, D. C. , USA
Page copyright © 2007 Richard E. Young and
All Rights Reserved.
- First online 19 November 2007
- Content changed 19 November 2007
Citing this page:
Young, Richard E. and Vecchione, Michael. 2007. Mastigoteuthis magna group. Version 19 November 2007 (under construction). http://tolweb.org/Mastigoteuthis_magna_group/65303/2007.11.19 in The Tree of Life Web Project, http://tolweb.org/