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Cases of teeth concrescence in the Pacific walrus (Odobenus rosmarus divergens)
Kryukova N.V.
P. 110-113
Three cases of concrescence of the fourth premolar with the first molar and one case of concrescence of the third and the fourth premolars are described in the Pacific walrus, Odobenus rosmarus divergens (Illiger, 1815). These cases represent 0.3% of the total number of inspected teeth (n = 1206) from 307 animals. All individuals (n = 3) were adult males aged 22–26 years old. The beginning of concrescence was found in animals ranging from 7 to 23 years old. The sections of concrescent teeth showed them to be joined by newly deposited layers of cementum.

DOI: 10.15298/rusjtheriol.16.1.10


  • Drehmer C.J., Fabian M.E. & Menegheti J.O. 2004. Dental anomalies in the Atlantic population of South American Sea Lion, Otaria Byronia (Pinnipedia, Otariidae): evolutionary implications and ecological approach // Latin American Journal of Aquatic Mammals. Vol.3. No.1. P.7–18.
  • Drehmer C.J., Sanfelice D. & Loch C. 2015. Dental anomalies in pinnipeds (Carnivora: Otariidae and Phocidae): occurrence and evolutionary implications // Zoomorphology. Vol.134. No.2. P.325–338.
  • Gunduz K., Sumer M., Sumer A. P. & Gunhan O. 2006. Concrescence of a mandibular third molar and a supernumerary fourth molar: Report of a rare case // British Dental Journal. Vol.200. No.3. P.141–142.
  • Klevezal’ G.A. & Kleinenberg S.E. 1967. [Age determination of mammals by layered structure of teeth and bone]. Moscow: Nauka. 144 p. [in Russian].
  • Kneżević A., Travan S., Tarle Z., Śutalo J., Janković B. & Ciglar I. 2002. Double tooth // Collegium Antropologicum. Vol.26. No.2. P.667–672.
  • Kryukova N.V. 2014. The method of age determination of the Pacific Walrus (Odobenus rosmarus divergens) using the layered structure of functional teeth // Biology Bulletin. Vol.41. No.8. P.681–689.
  • Lönnberg E. 1922. On some anomalies in the dentition of Phoca hispida // Bijdragen tot de Dierkunde. Vol.22. No.1. P.169–173.
  • Mansfield A.W. 1958. The biology of the Atlantic walrus, Odobenus rosmarus rosmarus (Linnaeus) in the eastern Canadian Arctic // Fisheries Research Board of Canada Manuscript Report Series (Biology). No.653. 146 p.
  • Miles A.E.W. & Grigson C. 1990. Colyer’s variations and diseases of the teeth of animals. Revised edition. Cambridge: Cambridge University Press. 676 pp.
  • Neville B.W., Damm D.D., Allen C.M. & Chi A.C. 2016. Abnormalities of teeth // Oral and Maxillofacial Pathology. Fourth edition. Canada: Elsevier, St. Louis. P.49–110.
  • Winer J.N., Arzi B., Leale D.M., Kass P.H. & Verstraete F.J.M. 2016. Dental and temporomandibular joint pathology of the walrus (Odobenus rosmarus) // Journal of Comparative Pathology. Vol.155. No.2–3. P.242–253.

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