鹅喉羚的年龄鉴定

AGE DETERMINATION OF GOITRED GAZELLE(Gazella subgutturosa)

本文以鹅喉羚为材料,采用双重附贴磨片法及蚀刻法确定角磨片上显示的生长层与角鞘上凸“嵴”的关系,并以第一下门齿(I_1)作切片所显示的年轮线进行验证。证明其角鞘上的凸“嵴”数量多少并不表示年龄大小,在一龄内无凸“嵴”,二、三龄均包含有4—5个凸“嵴”,四龄后亦为2—3个凸“嵴”组成一龄,真正的年龄线是角表凸“嵴”之后有一粗糙微凹的环纹。实验结果可应用于野外生态学调查,用以判断种群年龄及结构。

Goitred Gazelle (Gazclla subgutturosa) is one of precious ungulate of China. Fewer study were reported on its resource and biology. This paper presents that the methods of two sides grinding-segmenting and etching were used to determine the relation between the growth layers and convex ridges of horn sheath of Goitred Gazelle. There were seven samples of skull of Goitred Gazelle which were obtained in 1990's from Inner Mongolia Autonomous Region. The method was tested and verified by the cementum annulation appeared in the section of the first lower incisor ( I1). The sample (No. 90001) showed that all growth layers related to the rings which encircling the horn sheath. No rings appeared in the horn sheath of the first growth layer. The first ring was formed in its second winter, and one ring was formed in cvery winter afterwards. No convex ridge appeared on horn within its first age. From its 2 to 3 years old, there were 4-5 convex ridges within every one year. After 4 years old, there were 2-3 convex ridges within every one year. The true age annulations were the deeper rings with rough edges appeared on horn sheath, difftered from the convex ridges obviously. There1 were 5 age rings can be seen (Fig. 1). On the other hand, these age annulations appeared in the vertical sections of tooth (Fig. 2). On the vertical sections of tooth, a brown thin line was formed in its first year old; a wide line that pigment granule becomes deeper, appeared in its second year old; the third and the fifth year old was the same as the second year old; the fourth year old was the same as the first year old. This sample was obtained in its fifth winter. According the above, it can be drown that the numbers of convex ridges of horn did not indicate the age, the true age rings was that there was an unobvious rough ring behind the convex ridge. This result can be used in the field research of ecology and the investigation of the social structure.