Dental and Temporomandibular Joint Pathology of the Eastern Pacific Harbour Seal (Phoca vitulina richardii)

Publication date: Available online 29 March 2015 Source:Journal of Comparative Pathology Author(s): M.T. Aalderink , H.P. Nguyen , P.H. Kass , B. Arzi , F.J.M. Verstraete Skulls from 214 Eastern Pacific harbour seals (Phoca vitulina richardii) were examined macroscopically according to predefined criteria. The museum specimens were acquired from strandings along the west coast of the USA between 1909 and 2014. Ninety-eight skulls (45.8%) were from male animals, 108 (50.5%) from female animals and eight (3.7%) from animals of unknown sex. Their age varied from neonate to adult, with 101 adult animals (47.2%), 93 juvenile animals (43.5%) and 20 neonatal animals (9.3%). The majority of teeth were available for examination (90.0%); 7.5% of teeth were absent artefactually, 2.3% were deemed absent due to acquired tooth loss and 0.2% were absent congenitally. Males were no more likely than females to have either acquired tooth loss (P = 0.492) or congenitally absent teeth (P = 0.494). Adults had significantly more acquired tooth loss than juveniles (P <0.0001). All teeth were normal in morphology, except for four teeth from one skull that exhibited macrodontia. An unusual number of roots were found in most maxillary molar teeth; three roots were counted on six maxillary molar teeth and almost all other maxillary molar teeth available for examination had a fused root. Only 26 maxillary molar teeth exhibited two roots. Supernumerary teeth were associated with 13 n...
Source: Journal of Comparative Pathology - Category: Pathology Source Type: research