Morphological Study Of Deciduous Teeth Of Bactrian Camel

For thousands of years, the Bactrian camel has continuously been an important animal resource peculiar in arid and semi-arid areas in northwest of China, and it is remarkably adaptive to arid environment. This paper conducts an anatomical study of the morphological features of deciduous teeth of the Bactrian camel to probe into the morphological features that are adapted to the ecological environment in its evolution of assimilating food that are of small leaves and heavy spines and of high degree of lignifications.Through a comprehensive observation on morphological features of deciduous teeth of the Bactrian camel and measurement of the crown length, crown width and buccolingual width, it is found that among the superior teeth, the dental bodies of a pair of deciduous incisors and deciduous canines are relatively small but the dental roots are comparatively strong, which indicates a high top root ratio. These characteristics are related with the palatum durumis specialization into a thick and rough tooth plate to take in food. Its chief function is to hook and tear vegetable fibres. The mandibular deciduous incisors have shovel-shaped, long and smooth crowns and sharp incisor ridges which are easy to tackles stubby vegetable fibres. The mandibular deciduous canines are similar to incisors in form but they have sturdy dental roots which achieve the functions of cutting, biting and tearing. The dental roots of anterior teeth are cone-shaped single roots with high top root ratio. To be specific, the length of root is twice that of the crown, which increases the stability. Among the maxillary and mandibular deciduous premolars, the first deciduous prelomars have small dental bodies and they morphologically and functionally show the transitional state from anterior teeth to posterior teeth. The mesial-occlusal surface, narrow and small like canines, performs the function of biting. The mesio-dental roots are also cone-shaped like that of canines and they are of good stability. The distal-occlusal surface is slightly wide and performs chewing and grinding function. The distal-dental roots are relatively sturdy and they bear the bite force. As for the other deciduous premolars, they have wide crown width, buccolingual width and facies occlusalis dentis, which have more than one cusps and triangular ridge and sharp marginal ridges. They have three to four sturdy dental rootsof which the characteristics help the deciduous premolars grind stubby vegetable fibres and then help these fibres to be mechanically digested in the oral cavity effectively.In short, the uniqueness of the Bactrian camel's labial surface, facies linguialis dentis, mesial surface, distal surface incisal margin, facies occlusalis dentis, dental root and crown length of deciduous tooth, crown width and buccolingual width is adapted to their feeding on plants which are stubby and of heavy spines in deserts.