Magnapinna sp. B

Introduction

Magnapinna sp. B (called Magnapinna sp. A in Vecchione and Young, 2006) differs from all other species in the genus in its dark epidermal pigmentation. Unfortunately this squid was also badly damaged during capture but shares the presence of slender tentacles with the other Atlantic Magnapinna spp. This species is known from a single immature male (Bergen Museum cat. no. ZMBN 77634), 95 mm ML captured by the R/V G.O. SARS (MAR-ECO cruise super station 46, local station 374) at 42.8°N, 29.3°W on ll July 2004 (Vecchione and Young, 2006).

Brief diagnosis:

A Magnapinna without ...

• chromatophores  (ie, pigment not in chromatophores).

Characteristics

1. Arms
1. Proximal-arms with biserial suckers.
2. Diameter of large proximal-arm suckers 0.5 mm (fleshy diameter) with smooth inner rings and broad aperatures.
3. Distal-arms unknown due to damage.

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Figure. Oral and side views of large proximal-arm suckers of Magnapinna sp. B. Photograph from Vecchione and Young (submitted), modified.

2. Tentacles
1. Tentacles much narrower than adjacent arms.
2. Proximal-tentacles without suckers and without trace of aboral-lateral glandular lobes; skin missing.
3. Proximal-tentacle tapers gradually into distal-tentacle.
4. Distal-tentacle badly damaged but remnants of tiny suckers (without sucker rings) appear to be present.

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Figure. Ventrolateral view of the brachial crown of Magnapinna sp. B showing narrow tentacle (second appendage from top) relative to adjacent arms. Photograph from Vecchione and Young (2006), modified.

3. Head
1. Head badly damaged.
   
   
4. Funnel
1. Funnel locking-apparatus with elongate, oval depression.

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Figure. Frontal view of the funnel locking-apparatus, Magnapinna sp. B. Photograph from Vecchione and Young (submitted), modified.

5. Fins
1. Fins with damaged fringes but without obvious anterior lobes.
2. Fin length about 65% of ML.
   
   
6. Pigmentation
1. moderate epidermal purple-brown pigmentation on fins and mantle.
2. Oral surfaces of arms much more darkly pigmented.
3. Chromatophores absent.

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Figure. Pigmentation of Magnapinna sp. B. Left - Ventral view of a portion of the mantle and fins showing the epithelial pigmentation. Photograph from Vecchione and Young (2006), modified. Right - Oblique view of the buccal crown showing the dark pigmentation. Photograph by R. Young.

7. Measurements
   1. Mantle length - 95 mm; fin length - 62 mm; fin width - 66 mm; tail - 6, mm; tentacle width at base - 2.9 mm; arm IV width at base - 5.6 mm; diameter large arm suckers - 0.5 mm.
      

Comments

Magnapinna sp. B is separated from other species of the genus with narrow proximal-tentacles by the apparent absence of chromatophores, the relatively long free-mantle and the relatively broad aperatures of the proximal-arm suckers.

References

Vecchione, M. and R. E. Young. 2006. The squid family Magnapinnidae (Mollusca; Cephalopoda) in the North Atlantic with a description of Magnapinna atlantica, n. sp. Proc. Biol. Soc. Wash. 119 (3): 365-372.