Department of Animal and Biomedical Sciences, School of Life Science, Lanzhou University, Lanzhou, Gansu, China.
J Exp Zool A Ecol Integr Physiol. 2022 Jun;337(5):491-500. doi: 10.1002/jez.2583. Epub 2022 Feb 28.
Age determination provides crucial data regarding the life history of a species. Skeletochronology is considered to be a reliable method for age determination but is seldom applied to the genus Phrynocephalus (Agamidae) as it requires careful bone histological analysis to determine the formation of the lines of arrested growth (LAGs). We analyzed LAGs in different bones of Phrynocephalus vlangalii, a small, high-altitude lizard, and demonstrated that the phalanges are the best materials for skeletochronology in this species. We also found that the proximal half of the phalangeal diaphysis exhibits the most complete LAGs because of the unidirectional longitudinal growth of the phalange. Histologically, as the embryo bone that developed during the embryonic period was preserved even in very old individuals, no LAGs were eroded by endosteal resorption in the phalanges. The maximum age was 4 years for males and 5 years for females. It was determined that the age at maturity was 3 years for males and 2 or 3 years for females. On the basis of age determination, the age structures of both sexes were compared, and age-specific growth differences between the sexes were also analyzed. No differences in the snout-vent length were observed between sexes in any age group. However, the tail length of males aged 3 and above was significantly longer than that of females. Thus, the use of phalanges in the age determination of P. vlangalii is effective and can be widely applied to the ecological studies of this species as well as other small lizards.
年龄鉴定为物种的生活史提供了关键数据。骨骼年代学被认为是一种可靠的年龄鉴定方法，但很少应用于角蟾属（鬣蜥科），因为它需要仔细的骨骼组织学分析来确定生长静止线（LAGs）的形成。我们分析了高原蜥（Phrynocephalus vlangalii）不同骨骼中的 LAGs，高原蜥是一种小型高山蜥蜴，并证明指骨是该物种骨骼年代学的最佳材料。我们还发现，指骨骨干的近端半部分表现出最完整的 LAGs，因为指骨具有单向的纵向生长。组织学上，由于胚胎期发育的胚胎骨在非常老的个体中也被保留下来，因此指骨中的 LAGs 不会被骨内膜吸收侵蚀。最大年龄为雄性 4 岁，雌性 5 岁。确定的性成熟年龄为雄性 3 岁，雌性 2 岁或 3 岁。基于年龄鉴定，比较了两性的年龄结构，并分析了两性之间的年龄特异性生长差异。在任何年龄组中，两性的吻肛长都没有差异。然而，3 岁以上雄性的尾巴长度明显长于雌性。因此，使用指骨鉴定高原蜥的年龄是有效的，可以广泛应用于该物种以及其他小型蜥蜴的生态研究。
