Mastigoteuthis type beta

Introduction

We have examined a single specimen from sub-Antarctic waters that could represent a new taxon, but insufficient information is available to resolve this problem. Although no tentacle is attached, the two tentacles were found in the catch.

Brief diagnosis:

A member of the M. magna-group  ...

• with slightly toothed arm suckers.
• without pigmentation on most of the head, mantle and fins. (?)

Characteristics

1. Arms
   1. Arm suckers with distinct but somewhat variable dentition on distal margin of sucker rings.
      
   
   
   

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   Figure. Arms suckers of Mastigoteuthis "type Beta". Left - Oblique oral view of sucker 34, arm II. Right  - Oblique oral view of sucker 32, arms IV. Scanning electron micrographs by R. Young

   Scanning electron micrographs of the club suckers and enlarged views of the arm suckers can be seen here.
   

2. Head
   1. Beaks. A description of the beaks can be found here.
      
      
3. Funnel
   1. Funnel component of the locking apparatus is flask-shaped with a rather wide anterior stem and an elongate posterior bulb.
   
   
   

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   Figure. Funnel locking-apparatus of Mastigoteuthis "type beta". Left - Frontal of funnel component. Middle - Frontal view of mantle component. Right - Side view of Mantle component. Photographs by R. Young.

4. Photophores and pigmentation
   1. No trace of chromatophores or photophores was found.
   
   
   

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   Figure. Lateral view of the head of Mastigoteuthis "type beta", showing the apparent absence of chromatophores. Compare this photograph with the title photograph which shows what appears to be epithelial pigmentation around the eye. Photograph by R. Young.

Comments

Additional details of the description can be seen here. 

The shape of the funnel locking-apparatus is similar to that of Mastigoteuthis sp. A. The beaks show features intermediate between M. magna and Mastigoteuthis sp. A. The  absence of chromatophores, if real, is unique. Arm sucker dentition is present but slightly different from that of Mastigoteuthis sp. A, but more specimens are needed to determine if this difference is typical.

Distribution