BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Abstract. The aim of this work was to perform analysis of the skull morphology of red fox and raccoon dog and to examine their frontal sinuses (sinus frontalis) with the help of the methods of comparative anatomy and computed tomography. A total of 71 skulls of adult animals were used, 38 of red fox (22 male and 16 female) and 33 of raccoon dogs (21 male and 12 female). The most distinct morphological features were found in cranium bones, especially in frontal and occipital bones. The mandible was found to have four distinctive morphological features concentrated in the mandibular ramus (ramus mandibulae). The frontal sinuses in raccoon dog, unlike in red fox, occupy the entire surface of the zygomatic processes and are divided into small cavities by well-developed osseous partitions that are very thin in red fox. Computed tomography performed for the sagittal skull area revealed two prominent osseous partitions in the median part of the frontal sinuses in raccoon dogs and one partition in red fox. The maximum length, width and height of the frontal sinus cavity are larger in red fox than in raccoon dog (p < 0.001).

The present investigation endeavours to discern dental and non-dental pathologies affecting cranial structures of raccoon dogs, while focusing on cases of periodontitis. Furthermore, the study aims to conduct a comparative analysis based on sex and the nature of the pathologies encountered. The number of investigated skulls amounted to 126, including 76 males and 50 females. The predominant pathology identified was hypodontia, which accounted for 26.7% of males and 20% of females. Notably, the majority of hypodontia cases involved the absence of the mandibular third molar. Another noteworthy pathology was various stages of periodontitis, with rates ranging from 21.3% in males to 8% in females. Other pathologies, like tooth fractures and abrasion, were significantly less encountered. Excessive bone formation was relatively abundant and localized in specific areas—the parietal bone and the occipital regions. This tendency was observed in 8% of male cases and 6% of females. We found that the total number of dental and skull-bone pathologies is significantly more common in males than in females (p = 0.003). Additionally, the total number of various cases of periodontitis is more common in males too (p = 0.04).

The objective of the study was to investigate the lengths and widths of maxillary (P4, M1 and M2) and mandibular (M1, M2 and M3) molar teeth, lengths of dental rows and dental features of sexual dimorphism in the red fox. The correlation analysis between teeth measurements and dental row length was included too. The osteometric analysis was performed by the A. von den Driesch (1976) method. A total of 230 skulls and mandibles were investigated (n = 230): 113 males (n = 113) and 117 females (n = 117). The findings of the research revealed that most dimensions are higher in males compared with females (p < 0.001). Contrarily, Wilks' Lambda analysis showed results in the interval from 0.821 to 1, which leads to the conclusion that a teeth measurement study is unreliable to determine the sex of the red fox. The trustworthy measurements were the length of the whole dental arcade in the maxilla and mandible (UDR and LDR); Wilks' Lambda UDR = 0.860; LDR = 0.821; p < 0.001). Evaluation of the correlation between measurements revealed that results vary from very weak (0.047) to moderate strength (0.543). There were no strongly correlating measurements found. The correlation between the upper and lower molars with the length of the teeth arcade is quite weak, and only solitary measurements (M2, L and B) had a weak correlation.