Schlief Sierra C, Richman Joy M, Brink Kirstin S
Department of Earth Sciences, University of Manitoba, Winnipeg, Manitoba, Canada.
Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
J Anat. 2024 Oct 28. doi: 10.1111/joa.14151.
An understanding of the dynamics of bone growth is key to interpreting life-history parameters of vertebrates. In this study, we used fluorochrome labels in captive leopard geckos (Eublepharis macularius) to track bone growth and intraskeletal variability from embryonic to adult growth stages. Thirteen individuals were administered fluorochromes from pre-hatching to 4 years of age. The left tibia, fibula, femur, humerus, radius, and ulna were examined histologically and compared for differences in the number of labels within and between individuals at each sampled growth stage, and the amount of bone growth between labels was calculated. Results suggest that limb elements had differing growth rates; the fibula grew the fastest per day on average and the femur grew the slowest per day on average. All labels administered in ovo were still present in all limb elements in adults except for the tibia, suggesting growth marks are not lost in most elements and accurate calculations of growth rates could be performed in individuals up to 3 years old. All ex ovo labels were accounted for; however, when two fluorochromes were administered 3 weeks apart, the labels could not be differentiated from each other due to the new bone not being deposited at a quantifiable level. Overall, the tibia in leopard geckos is the least reliable limb bone to use for skeletochronology and the humerus, radius, and fibula preserve the longest growth record. This research highlights that, as in other extinct and extant animals, patterns of bone growth are not consistent across reptiles. This study adds to the growing body of knowledge on growth variability in reptiles.
了解骨骼生长的动态过程是解读脊椎动物生活史参数的关键。在本研究中，我们在圈养的豹纹守宫（Eublepharis macularius）中使用荧光色素标记来追踪从胚胎期到成年期的骨骼生长和骨骼内部的变异性。13只个体从孵化前到4岁都被注射了荧光色素。对左胫骨、腓骨、股骨、肱骨、桡骨和尺骨进行了组织学检查，并比较了每个采样生长阶段个体内部和个体之间标记数量的差异，同时计算了标记之间的骨骼生长量。结果表明，四肢骨骼的生长速度不同；腓骨平均每天生长最快，股骨平均每天生长最慢。除胫骨外，所有在卵内注射的标记在成年个体的所有四肢骨骼中仍然存在，这表明大多数骨骼中的生长标记不会丢失，并且可以对3岁以下个体的生长速度进行准确计算。所有出壳后的标记都有记录；然而，当相隔3周注射两种荧光色素时，由于新骨没有以可量化的水平沉积，标记无法相互区分。总体而言，豹纹守宫的胫骨是用于骨骼年代学最不可靠的四肢骨骼，而肱骨、桡骨和腓骨保留的生长记录最长。这项研究强调，与其他已灭绝和现存的动物一样，爬行动物的骨骼生长模式并不一致。这项研究增加了关于爬行动物生长变异性的知识储备。
