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Cephalopod beak

From Wikipedia, the free encyclopedia
Body part of cephalopods
The beak of agiant squid

Allextantcephalopods have a two-partbeak, orrostrum, situated in the buccal mass (mouthparts) and surrounded by the muscularhead appendages. Thedorsal (upper)mandible fits into theventral (lower) mandible and together they function in a scissor-like fashion.[1][2] The beak may also be referred to as themandibles orjaws.[3]

Fossilised remains of beaks are known from a number of cephalopod groups, both extant and extinct, includingsquids,octopuses,belemnites, andvampyromorphs.[3][4][5][6][7][8][9][excessive citations]Aptychi - paired plate-like structures found inammonites - may also have been jaw elements.[10][11][12][13]

Composition

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

Composed primarily ofchitin and cross-linkedproteins,[14][15][16][17] beaks are more or less indigestible and are often the only identifiable cephalopod remains found in the stomachs of predatory species such assperm whales.[18] Cephalopod beaks gradually become less stiff as one moves from the tip to the base, a gradient that results from differing chemical composition. In hydrated beaks of theHumboldt squid (Dosidicus gigas) this stiffness gradient spans twoorders of magnitude.[19]

  • Side view of the lower beak of Chiroteuthis picteti (3.6 mm LRL, 160 mm ML (estimate)),
    Side view of the lower beak ofChiroteuthis 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)
    Side view of the upper beak from the same specimen (2.7 mm URL)[1]

Measurements

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Giant squid beak and associated muscles with hand for scale

The abbreviationsLRL andURL are commonly used inteuthology to refer tolower rostral length andupper rostral length, respectively. These are the standard measures of beak-size inDecapodiformes;hood length is preferred forOctopodiformes.[18] They can be used to estimate themantle length and total body weight of the original animal as well as the total ingestedbiomass of the species.[20][21][22][23][24][25][26]

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

References

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  1. ^abcYoung, 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. ^abTanabe, K., Y. Hikida & Y. Iba (2006). Two coleoid jaws from the Upper Cretaceous of Hokkaido, Japan.Journal of Paleontology80(1): 138–145.doi:10.1666/0022-3360(2006)080[0138:TCJFTU]2.0.CO;2
  4. ^Zakharov, Y.D. & T.A. Lominadze (1983). New data on the jaw apparatus of fossil cephalopods.Lethaia16(1): 67–78.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 History2: 23–34.
  6. ^Tanabe, K. & N.H. Landman (2002). Morphological diversity of the jaws of Cretaceous Ammonoidea.Abhandlungen der Geologischen Bundesanstalt, Wien57: 157–165.
  7. ^Tanabe, K., P. Trask, R. Ross & Y. Hikida (2008). Late Cretaceous octobrachiate coleoid lower jaws from the north Pacific regions.Journal of Paleontology82(2): 398–408.doi:10.1666/07-029.1
  8. ^Klug, C., G. Schweigert, D. Fuchs & G. Dietl (2010). First record of a belemnite preserved with beaks, arms and ink sac from the Nusplingen Lithographic Limestone (Kimmeridgian, SW Germany).Lethaia43(4): 445–456.doi:10.1111/j.1502-3931.2009.00203.x
  9. ^Tanabe, K. (2012). Comparative morphology of modern and fossil coleoid jaw apparatuses.Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen266(1): 9–18.doi:10.1127/0077-7749/2012/0243
  10. ^Morton, N. (1981). Aptychi: the myth of the ammonite operculum.Lethaia14(1): 57–61.doi:10.1111/j.1502-3931.1981.tb01074.x
  11. ^Morton, N. & M. Nixon (1987). Size and function of ammonite aptychi in comparison with buccal masses of modem cephalopods.Lethaia20(3): 231–238.doi:10.1111/j.1502-3931.1987.tb02043.x
  12. ^Lehmann, U. & C. Kulicki (1990). Double function of aptychi (Ammonoidea) as jaw elements and opercula.Lethaia23: 325–331.doi:10.1111/j.1502-3931.1990.tb01365.x
  13. ^Seilacher, A. (1993). Ammonite aptychi; how to transform a jaw into an operculum?American Journal of Science293: 20–32.doi:10.2475/ajs.293.A.20
  14. ^Saunders, W.B., C. Spinosa, C. Teichert & R.C. Banks (1978)."The jaw apparatus of RecentNautilus and its palaeontological implications"(PDF). Archived fromthe original(PDF) on 2016-10-05. Retrieved2016-09-12.Palaeontology21(1): 129–141.
  15. ^Hunt, S. & M. Nixon (1981). A comparative study of protein composition in the chitin-protein complexes of the beak, pen, sucker disc, radula and oesophageal cuticle of cephalopods.Comparative Biochemistry and Physiology Part B: Comparative Biochemistry68(4): 535–546.doi:10.1016/0305-0491(81)90071-7
  16. ^Miserez, A., Y. Li, J.H. Waite & F. Zok (2007)."Jumbo squid beaks: Inspiration for design of robust organic composites"(PDF). Archived fromthe original(PDF) on 2016-03-05. Retrieved2012-01-08.Acta Biomaterialia3(1): 139–149.doi:10.1016/j.actbio.2006.09.004
  17. ^Organic composite is exceptionally robust: jumbo squidArchived 2012-01-06 at theWayback Machine. Ask Nature.
  18. ^abClarke, M.R. (1986).A Handbook for the Identification of Cephalopod Beaks. Oxford University Press, Oxford.
  19. ^Miserez, A., T. Schneberk, C. Sun, F.W. Zok & J.H. Waite (2008). The transition from stiff to compliant materials in squid beaks.Science319(5871): 1816–1819.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), Zoology8(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 Bulletin80(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 fromthe original(PDF) on 2016-03-04. Retrieved2013-02-03. NOAA Technical Report NMFS 17, NOAA/National Marine Fisheries Service.
  23. ^Jackson, G.D. (1995). The use of beaks as tools for biomass estimation in the deepwater squidMoroteuthis ingens (Cephalopoda: Onychoteuthidae) in New Zealand waters.Polar Biology15(1): 9–14.doi:10.1007/BF00236118
  24. ^Jackson, G.D. & J.F. McKinnon (1996). Beak length analysis of arrow squidNototodarus sloanii (Cephalopoda: Ommastrephidae) in southern New Zealand waters.Polar Biology16(3): 227–230.doi:10.1007/BF02329211
  25. ^Jackson, G.D., N.G. Buxton & M.J.A. George (1997). Beak length analysis ofMoroteuthis ingens (Cephalopoda: Onychoteuthidae) from the Falkland Islands region of the Patagonian Shelf.Journal of the Marine Biological Association of the United Kingdom77(4): 1235–1238.doi:10.1017/S0025315400038765
  26. ^Gröger, J., U. Piatkowski & H. Heinemann (2000)."Beak length analysis of the Southern Ocean squidPsychroteuthis glacialis (Cephalopoda: Psychroteuthidae) and its use for size and biomass estimation".Polar Biology23(1): 70–74.doi:10.1007/s003000050009

Further reading

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Cephalopod anatomy
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Illex illecebrosus anatomy
Pelagic octopus Tremoctopus
Dissected Sepia officinalis
Mantle &
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General
Developmental stages:Spawn →Paralarva (Doratopsis stage) → Juvenile → Subadult → Adult •Egg fossils •Protoconch (embryonic shell)
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