Note

Magnapinna atlantica: Beak description

Michael Vecchione and Richard E. Young
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Figure. Ventral views of the two specimens of M. atlantica from which the beaks were examined. Left - 127 mm ML, mature male.  Right - 53 mm ML, paratype, juvenile male.

Lower Beak

Mature male, 127 mm ML: Shoulder with sharp wing-fold covering jaw angle and extending onto rostrum; lateral wall esentially flat, lateral-wall fold barely detectible, ie, virtually absent; jaw angle acute, low rounded tooth on one side, eroded on other side; rostrum short with constriction near tip; beak shape low and broad; Height/length (c/d) = 0.6; LRL = 1.6 mm (measured to inner edge of medial shoulder blade). Wing length/outer rostral length (b/a) = 4.3. Wing angle = 100°. Hood to crest ratio = 0.67. Crest to base ratio = 0.63. Rostral base/baseline = 0.15.  Hood close to crest. Crest with irregular bumps apparently due to damage during growth. Without notch in lateral wall. Hood-wing broad. No notch or indentation on posteromedial hood. Free corners of lateral wall widely spread. No cartilage on mature beak. Jaw angle without step. Angle point cannot be detected in dark beak. Jaw edge blunt. Crest broad, apparently unthickened.

Juvenile male, 53 mm ML: Beak very small, LRL = 0.3 mm, length from rostral tip to wing fold in profile = 0.54 mm.  Lateral wall extends well along jaw edge with large, tooth-like structures. No lateral wall fold. Sharp wing fold. Top of rostrum curved. Hood well above crest. Slight concavity in edge of posteromedial hood. Angle point present but does not extend beyond shoulder. Light pigmentation over most of lateral wall.

The juvenile lower beak looks quite different from that of the adult male which is not unexpected. 

Lower beak photographs

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Figure. Side view of the lower beak of M. atlantica. Left - 127 mm ML. Right - 53 mm ML.

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Figure. Oblique views of the lower beak of M. atlantica, 127 mm ML. 

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Click on an image to view larger version & data in a new window

Figure. Oblique views of the lower beak of M. atlantica, 53 mm ML. 

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Click on an image to view larger version & data in a new window

Figure. Oblique views of the lower beak of M. atlantica, 127 mm ML.

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Click on an image to view larger version & data in a new window

Figure. Oral-oblique views of the right and left jaw angles of M. atlantica lower beak. 

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Figure. Views of the lower beak of M. atlantica. Left - Oblique view, 127 mm ML. Middle - Top view, 127 mm ML. Right - Top view, 53 mm ML.

Upper beak 

Mature male, 127 mm ML: Upper beak with short, broad rostrum, hood high above crest, crest strongly curved. Lateral walls broadly spread. Lateral walls with strong undulation. Pallet virtually flat. Outer and inner shoulder blades blunt. Outer shoulder blade conceals inner blade when viewed laterally. Crest beneath hood without ridges. Outer rostral length/hood length = 0.20. Hood length/crest length = 0.55. Outer rostral length/hood height above crest = 0.73.

Juvenile male, 53 mm ML: Separation of inner and outer shoulder blades present only at extreme anterior end of shoulder; most of anterior margin of shoulder appears as a single blade. Rostral tip with distinct hook. Undulations of the lateral wall present but not as pronounced as in adult. 

Upper beak photographs 

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Click on an image to view larger version & data in a new window

Figure. Side views of the upper beak of M. atlantica. Left - 127 mm ML. Right - 53 mm  ML, size is indicated by the tip of an insect pin in the photograph.

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Click on an image to view larger version & data in a new window

Figure. Oblique views of the upper beak of M. atlantica

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Click on an image to view larger version & data in a new window

Figure. Frontal views of the upper beak of M. atlantica, 127 mm ML.

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Click on an image to view larger version & data in a new window

Figure. Oblique views of the shoulder and pallet of the upper beak of M.atlantica, 53 mm ML

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Click on an image to view larger version & data in a new window

Figure. Views of the upper beak of M. atlantica. Left - Oral view, antrior end, 53 mm ML. Curve at bottom of photograph is the hood seen through the crest. Middle - Oral view, 127 mm ML. Right - Posterior view, 127 mm ML.

Beak photographs by R. Young.
About This Page


National Museum of Natural History, Washington, D. C. , USA


University of Hawaii, Honolulu, HI, USA

Page: Tree of Life Magnapinna atlantica: Beak description Authored by Michael Vecchione and Richard E. Young. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

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