Mastigoteuthis magna Joubin, 1913

Introduction

Joubin 1913 (as redescribed in 1920) based M. magna on a single specimen of 160 mm ML from the Sargasso Sea. It appears now to be one of the more common species of Mastigoteuthis in the North Atlantic (personal observations).

Diagnosis

A mastigoteuthid ...

• without photophores.
• with flask-shaped funnel locking-groove.
• with fin length equal to fin width.

Characteristics

image info

Figure. Side view of a club sucker of M. magna, holotype. Drawing from Joubin (1920).

image info

Figure. Ventral view of the funnel component of the funnel locking-apparatus of M. magna, holotype . Drawing from Joubin (1920).

1. Arms
1. Arm suckers with smooth inner rings.
2. Tentacles
1. Club length 80% of tentacle length (Joubin, 1920).
2. Proximally suckers in narrow band that gradually broadens; at mid-club suckers cover 3/4 of tentacle (Joubin, 1920).
3. Club suckers minute with smooth inner rings (Joubin, 1920).
3. Funnel
   1. Mantle component of the funnel locking-apparatus a "rectilinear ridge narrow anteriorly and slightly wider posteriorly" (Joubin, 1920).
   2. Funnel component an "auricular-like groove" (Joubin, 1920). This is a flask-shaped groove.
4. Mantle
   1. Skin tubecules absent from mantle and elsewhere.
5. Fins (Joubin, 1920)
1. Fin length (without tail) 66% of ML.
2. Fin width 79% if ML (without tail); assumming a 20 mm tail the FW becomes 71% of ML
3. Fin width 120% of fin length (without tail).
6. Photophores
   1. Photophores absent.
7. Measurements

   Source	Joubin, 1920
   Sex	?
   Mantle length	160
   Mantle width	54
   Head length	42
   Head width	43
   Fin length	105 (without tail)
   Fin width	127
   Arm I, length	80
   Arm II, length	105
   Arm III, length	82
   Arm IV, length	172
   Arm I, sucker no.	135
   Arm II, sucker no.	120+
   Arm III, sucker no.	112
   Arm IV, sucker no.	109
   Tentacle length	480
   Club length	390

Comments

This description is taken from Joubin (1920). This species is very similar to M. inermis but differs in the greater width of the fins and the fewer arm suckers. The differences between these species, however, requires confirmation. The flask-shaped groove in the funnel organ, the tiny club suckers and absence of photophores distinguishes M. magna and M. inermis from all other members of the genus.

Distribution

References

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