Mastigoteuthis magna Joubin, 1913

Introduction

M. magna  appears to be one of the more common species of Mastigoteuthis in the temperate to tropical Atlantic. The description of the holotype by Joubin (1920) can be seen here.

Brief diagnosis:

A member of the M. magna group ...

• without photophores.
• with smooth-ringed arm suckers.

Characteristics

1. Arms
   1. Arm suckers with smooth inner rings.
   2. Largest suckers of arms IV larger than those of other arms.
      
   

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   Figure. Oral views of large suckers from  arms of M. magna, Left - Dive 3750, immature female, 111 mm ML; light microscope. Right - DE011-003, arm III, sucker 6, 135 mm ML; scanning electron microscope. Photographs by R. Young.

More scanning electron microscopy of arm and club suckers can be seen here.

2. Head
   1. Beaks. A description of the beaks can be found here.
      
      
3. Funnel
   1. Mantle component of funnel locking-apparatus with straight, anterior groove and broad, posterior cup
   

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   Figure. Funnel locking-apparatus of M. magna. Left - Frontal view of funnel component, 111 mm ML. Middle - Frontal view of mantle component, 111 mm ML. Right -  Sta. WH512, 32°47'N, 16°24'W, head only. Photographs by R. Young.

4. Photophores and pigmentation
   1. Skin, except oral surfaces, covered with dense packing of chromatophores containing a deep, brilliant red pigment.
   2. Photophores absent.
   3. No trace of ringed chromatophores or white spheres.
      
   

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   Figure. Left - Frontal view of the chromatophores of M. magna, off New England, fresh, showing numerous chromatophores. Region of squid unknown. Photograph by M. Vecchione. Right - Ventrolateral view of a damaged portion of the ventral head of M. magna, 40°N,67°W, 160 mm ML, showing dense packing of chromatophores and the subchromatophore layer (damaged region) but without any indication of photophores. Photograph by R. Young.

Comments

More details of the description of M. magna can be found here.

Distribution

Type locality: Sargasso Sea of the North Atlantic at 31°45'N, 42°39'W. Apparently M. magna occurs throughout the tropical and warm temperate Atlantic, At least from 50°N, 27°W (MARECO record) to 40°S, 26°W (FFS WALTHER HERWIG record). Reported from the Indian Ocean (Nesis, 1982/87) but this could a species of the M. magna-group that was not recognized at the time of this publication.

References

Joubin, L. 1920. Céphalopodes provenant des Campagnes de la Princesse Alice (1898-1910). 3e Serie. Monaco.