Martialia hyadesi Rochebrune & Mabile 1889

Introduction

Martialia hyadesi was originally described from a single specimen in 1882 and redescribed in 1990 (Rodhouse and Yearman, 1990). By 1986, twenty thousand tons of M. hyadesi were taken as bycatch in the Illex argentinus fishery. M. hyadesi is a moderate-sized ommastrephid reaching a maximum size of at least 319 mm ML.

The specific name of M. hyadesi presumably reflects that of the ship's surgeon on Charcot's ship the POUQUOIS PAS whose name was Hyades and whose ability to cure mal de mer was revered.  

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Figure. Dorsal and ventral views of M. hyadesi. Drawings from Rodhouse and Yeatman (1990).

The original description can be found here.

Brief diagnosis: 

A member of the Todarodinae with ...

• tentacular club extending nearly to base of tentacle and not expanded.
• well developed trabeculae associated with reduced protective membranes on arms and tentacles.
  

Characteristics

1. Arms
   1. Arms with poorly developed protective membranes but large and prominent trabeculae.
   2. Right arm IV hectocotylized; left arm IV slightly modified.
      
      1. Distal third of right arm IV with small suckers on long stalks; on ventral side, trabeculae form rounded flaps; on dorsal side trabeculae without free ends (free ends of trabeculae gradually diminish in size over proximal two thirds of arm until trabeculae present only as rounded bases to suckers).
      2. Suckers of distal third of left arm IV sometimes with elongated stalks.
         
      

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      Figure. Oral view of arms IV of a male M. hyadesi showing the hectocotylized right arm and the dentition of one sucker. Hectocotylus = 105 mm. Drawings from Rodhouse and Yeatman (1990).

      

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      Figure. Oral view of the hectocotylized right arm of M. hyadesi. Drawing from Roeleveld (1988) shows some differences with the previous drawing.  

2. Tentacles
   
   1. Tentacles much like enlarged arms; most of tentacle occupied by club.
      
   2. Tentacular club not expanded (round in cross-section); not clearly differentiated into carpus, manus and dactylus.
   3. Protective membrane poorly developed; trabeculae strongly developed.
      
   4. Tentacular stalks with 3-5 free trabeculae proximal to first suckers on each margin.
      
   

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   Figure. Oral views of the right arms and tentacle of M. hyadesi, female, arm IV = 110 mm. Drawing from Rodhouse and Yeatman (1990).

3. Head
   
   1. Beaks: Descriptions can be found here: Lower beak; upper beak.
      
      

Comments

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

Ecology

Beaks and soft parts from the regurgitations and gut contents of wandering (Diomedea exulans), grey-headed (Diomedea chrysostoma) and black-browed (Diomedea melanophris) albatross chicks from Bird Island, South Georgia, indicate that M. hyadesi is an important component of the cephalopod diet of these birds and that it is ecologically important in the sub-Antarctic waters of the south Atlantic (Rodhouse, 1990).

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Figure. Wandering Albatross chick at Bird Island, South Georgia with some still
warm and steaming, part digested squid (probably Martialia) he has just chucked up (arrow). ©

Because of the abundance of M. hyadesi, commercial fishing trials have been carried out in the vicinity of South Georgia, and 8 tons of squid were caught at the Antarctic Polar Front (Rodhouse, 1990).

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Figure. Ventral view of M. hyadesi caught on a jig of a Japanese jigger undertaking exploratory fishing north of South Georgia at the Antarctic Polar Front. Right photograph is an enlargement of the squid in the left photograph. ©

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Figure. M. hyadesi being packed for freezing on a Korean jiigger doing exploratory
fishing north of South Georgia at the Antarctic Polar Front. ©

Distribution

Type locality: Cook Bay, Cape Horn. The holotype is in poor condition and deposited in the Museum Nationale d'Histoire Naturelle, Paris.

A map of the distribution of M. hyadesi can be found here.

Other Names for Martialia hyadesi Rochebrune & Mabile 1889

• Martialia Rochebrune & Mabile 1889

References

Rodhouse, P. G. and J. Yeatman. 1990. Redescription of Martialia hyadesi Rochebrune and Mabille, 1889 (Mollusca: Cephalopoda) from the Southern ocean.Bull. Br. Mus. nat. Hist (Zool.), 56(2): 135-143.

Roeleveld, M. A. 1988. Generic interrelationships within the Ommastrephidae (Cephalopoda). P.277-314. In: M. R. Clarke and E. R. Trueman (eds.). The Mollusca. Vol. 12. Paleontology and Neontology of Cephalopods. Academic Press, N.Y., 355pp.