Magnapinna talismani

Introduction

Magnapinna talismani is known from a single damaged specimen that came from 34°46'N, 36°11'W (south of the Azores, North Atlantic). The squid was caught in an open bottom trawl, that fished to a depth of 3175 m. This capture location is very near that of Magnapinna sp. B.

Diagnosis

• small white nodules on the ventral surface of the fins.

Characteristics

Description

1. Arms
   1. Suckers on proximal-arm in two series and closely packed.
   2. Proximal-arm suckers with smooth inner rings.
   3. Arms badly damaged.
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   Figure. Proximal-arm suckers of M. talismani, holotype. Left - Side view of a portion of the proximal-arm. Middle - Oral view of an arm sucker. Photographs by R. Young. Right - Oblique view of an arm sucker. Drawing from Fischer and Joubin (1907).

2. Tentacle
   1. Tentacles badly damaged; long, thin and cylindrical; much thinner than the arms at their base.
   2. In contrast to the original description and illustration (see drawing above), no evidence of an discreet club is present.
   3. No disinct transition between proximal- and distal-tentacle.
   4. Distal-tentacle apparently with numberous, small suckers ( photograph and drawing below).
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   Figure. Tentacles of M. talismani, holotype. Left - Ventral (?) view of the brachial crown showing slender proximal-tentacle adjacent to much thicker arms. Photograph from Vecchione and Young (submitted), modified. Middle - Side view of a tentacle sucker. Drawing from Fischer and Joubin (1907). Right - Appendage free in jar with holotype, apparently a portion of the tentacle. Note what appear to be small suckers on the badly abraided appendage. Photographs by R. Young

3. Funnel
   1. Funnel locking-apparatus with oval depression and possible tragus (from F&J). Both funnel locking-cartilages are distorted in the holotype and the presence or absence of a weak tragus is uncertain but unlikely.
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   Figure. Frontal view of the funnel locking-apparatus of M. talismani, holotype. Drawing from Fischer and Joubin (1907).

4. Mantle
   1. Mantle length 61 mm (from F&J).
      
      
5. Fins
   1. Ventral surface of fins covered with white nodules (from F&J).
   2. Fin length - 54 mm; fin width - 53 mm (from F&J).
   3. No tail present.
   4. Apex angle of fins nearly 90°.
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      Figure. Dorsal view of the fins and mantle of M. talismani, holotype. A glass slide has been placed over the posterior tip of the fins to keep them flat. Photograph by R. Young.

   5. Gladius
   1. Gladius not removed. The length of the gladius cannot be determined as the anterior end is frayed indicating that some of it may be missing.

Comments

The text, translated into English, of the original description by Fischer and Joubin (1907) can be found here.

Very little new information can be derived from our examination of the holotype. Information from the original description that we did not confirm is marked "from F&J" above. This squid was badly damaged when captured and has not survived well in preservation. The poor condition of the holotype which has lost most species-level characters makes comparisons with other species difficult. The holotype certainly belongs in the Magnapinnidae and shares with all Atlantic forms the slender proximal-tentacles. It is most similar to Magnapinna sp. A and sp. C. Of the two only Magnapinna sp. A is well described. Several features separate M. talismani and Magnapinna sp. A. (1) The fins of M. talismani extend to the tip of the gladius forming a broad apex. This shape is evident in the above illustration and photograph. Although the posterior tip of the fin of Magnapinna sp. A is damaged, its shape in life would appear to have been different than that of M. talismani. (2) The tentacles of M. talismani show no trace of glandular regions. The absence could be due to damage but this seems unlikely. The ventral surface of the fins is covered with white "nodules," as seen in the title illustration, that were considered by the authors to be possible photophores. No such structures are found in Magnapinna sp. A. No nodules presently remain on the holotype of M. talismani. These structures may have been some type of artifact, but there is no way to determine this at present. M. talismani appears to have a much larger buccal mass, thicker arms and larger suckers than Magnapinna sp. A.

image info

Figure. Oral-oblique views of the buccal region of the holotypes of Magnapinna sp. A (left) and M. talismani (right). Photograph from Vecchione and Young (submitted), modified.

These features suggest that either M. talismani was much larger than original measurements indicate or that it's morphometrics are much different from those of Magnapinna sp. A. The mantle length (61 mm) and fin length (54 mm) of M. talismani are nearly identical with those of Magnapinna sp. A (59 mm, 53 mm) but the diameter of the buccal mass of M. talismani is 1 3/4 times greater. Fischer and Joubin (1907) conclude that M. talismani had shrunk by 25% when described judging from an illustration made immediately after capture. This correction gives a proper mantle length of 81 mm or 1 1/4 times that of Magnapinna sp. A (for the latter we included the tail with the mantle length giving an adjusted ML of 63 mm, and assumed no shrinkage). These adjustments still leave the buccal masses differing by a factor of 1.4. Some other features of the original description that seem different (eg, lack of an nuchal cartilage, presence of a distinct club, possible antitragus) were incorrect or probably incorrect.

Nomenclature

This M. talismani was originally placed in the genus Chiroteuthopsis which is currently considered a junior synonym of Mastigoteuthis. Mastigoteuthis talismani was placed in Magnapinna by Vecchione and Young (submitted).

References

Fischer, H. and L. Joubin (1907). Expéditions scientifiques du TRAVAILLEUR et du TALISMAN. Céphalopodes, 8: 313-353.

Vecchione, M., Young R. E. Submitted. The squid family Magnapinnidae (Mollusca; Cephalopoda) in the North Atlantic with a description of a new species.