Cephalopod beak

Source: Wikipedia, the free encyclopedia.
The beak of a giant squid

All

ventral (lower) mandible and together they function in a scissor-like fashion.[1][2] The beak may also be referred to as the mandibles or jaws.[3] These beaks are different from bird beaks
because it crushes bone while most birds don't.

Fossilised remains of beaks are known from a number of cephalopod groups, both extant and extinct, including

ammonites – may also have been jaw elements.[10][11][12][13]

Composition

The beak of a giant squid, surrounded by the buccal mass and limbs

Composed primarily of

orders of magnitude.[19]

  • Side view of the lower beak of Chiroteuthis picteti (3.6 mm LRL, 160 mm ML (estimate))[1] 3D red cyan glasses are recommended to view this image correctly.
    Side view of the lower beak of Chiroteuthis picteti (3.6 mm LRL, 160 mm ML (estimate))[1]
    3D red cyan glasses are recommended to view this image correctly.
  • Side view of the upper beak from the same specimen (2.7 mm URL)[1]
    Side view of the upper beak from the same specimen (2.7 mm URL)[1]

Measurements

Giant squid beak and associated muscles with hand for scale

The abbreviations LRL and URL are commonly used in teuthology to refer to lower rostral length and upper rostral length, respectively. These are the standard measures of beak size in Decapodiformes; hood length is preferred for Octopodiformes.[18] They can be used to estimate the mantle length and total body weight of the original animal as well as the total ingested biomass of the species.[20][21][22][23][24][25][26]

  • Lower rostral length
    Lower rostral length
  • Upper rostral length
    Upper rostral length

References

  1. ^ a b c Young, R.E., M. Vecchione & K.M. Mangold (1999). Cephalopoda Glossary. Tree of Life Web Project.
  2. ^ Young, R.E., M. Vecchione & K.M. Mangold (2000). Cephalopod Beak Terminology. Tree of Life Web Project.
  3. ^
    doi:10.1666/0022-3360(2006)080[0138:TCJFTU
    2.0.CO;2]
  4. doi:10.1111/j.1502-3931.1983.tb02000.x
  5. ^ Kanie, Y. (1998). New vampyromorph (Coleoidea: Cephalopoda) jaw apparatuses from the Late Cretaceous of Japan. Bulletin of Gumma Museum of Natural History 2: 23–34.
  6. ^ Tanabe, K. & N.H. Landman (2002). Morphological diversity of the jaws of Cretaceous Ammonoidea. Abhandlungen der Geologischen Bundesanstalt, Wien 57: 157–165.
  7. doi:10.1666/07-029.1
  8. doi:10.1111/j.1502-3931.2009.00203.x
  9. doi:10.1127/0077-7749/2012/0243
  10. doi:10.1111/j.1502-3931.1981.tb01074.x
  11. doi:10.1111/j.1502-3931.1987.tb02043.x
  12. doi:10.1111/j.1502-3931.1990.tb01365.x
  13. doi:10.2475/ajs.293.A.20
  14. ^ Saunders, W.B., C. Spinosa, C. Teichert & R.C. Banks (1978). "The jaw apparatus of Recent Nautilus and its palaeontological implications" (PDF). Archived from the original (PDF) on 2016-10-05. Retrieved 2016-09-12. Palaeontology 21(1): 129–141.
  15. doi:10.1016/0305-0491(81)90071-7
  16. doi:10.1016/j.actbio.2006.09.004
  17. ^ Organic composite is exceptionally robust: jumbo squid Archived 2012-01-06 at the Wayback Machine. Ask Nature.
  18. ^ a b Clarke, M.R. (1986). A Handbook for the Identification of Cephalopod Beaks. Oxford University Press, Oxford.
  19. doi:10.1126/science.1154117
  20. ^ Clarke, M.R. (1962). The identification of cephalopod "beaks" and the relationship between beak size and total body weight. Bulletin of the British Museum (Natural History), Zoology 8(10): 419–480.
  21. ^ Wolff, G.A. (1981). "A beak key for eight eastern tropical Pacific cephalopod species with relationships between their beak dimensions and size" (PDF). Fishery Bulletin 80(2): 357–370.
  22. ^ Wolff, G.A. (1984). "Identification and estimation of size from the beaks of 18 species of cephalopods from the Pacific Ocean" (PDF). Archived from the original (PDF) on 2016-03-04. Retrieved 2013-02-03. NOAA Technical Report NMFS 17, NOAA/National Marine Fisheries Service.
  23. doi:10.1007/BF00236118
  24. doi:10.1007/BF02329211
  25. doi:10.1017/S0025315400038765
  26. doi:10.1007/s003000050009

Further reading

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