Data from: Secondary osteons scale allometrically in the mammalian humerus and femur

Intra-cortical bone remodelling is a cell-driven process that replaces existing bone tissue with new bone tissue in the bone cortex, leaving behind histological features called secondary osteons. While the scaling of bone dimensions on a macroscopic scale is well known, less is known about how the spatial dimensions of secondary osteons vary in relation to the adult body size of the species. We measured the cross-sectional area of individual intact secondary osteons and their central Haversian canals in transverse sections from 40 stylopodial bones of 39 mammalian species. Scaling analysis of our data shows that mean osteonal resorption area (negative allometry, exponent 0.23, R2 0.54, p<0.005) and Haversian canal area (negative allometry, exponent 0.31, R2 0.45, p<0.005) are significantly related to adult body mass, independent of phylogeny. This study is the most comprehensive of its kind to date, and allows us to describe overall trends in the scaling behaviour of secondary osteon dimensions, supporting the inference that osteonal resorption area may be limited by the need to avoid fracture in smaller mammalian species, but the need to maintain osteocyte viability in larger mammalian species.皮质内骨重塑（intra-cortical bone remodelling）是一种由细胞驱动的过程，该过程在骨皮质中以新骨组织替换原有骨组织，并留下被称为次级骨单位（secondary osteons）的组织学特征。尽管宏观尺度下骨尺寸的缩放规律已被广泛认知，但目前对于次级骨单位的空间尺寸如何随物种成体体型发生变化的认知仍相对有限。我们对取自39种哺乳动物的40块近段肢骨（stylopodial bones）的横切片，测量了其中单个完整次级骨单位及其中央哈弗斯管（Haversian canal）的横截面积。对所获数据的缩放分析结果显示，平均骨单位吸收面积（负异速生长，指数0.23，R²=0.54，p<0.005）与哈弗斯管面积（负异速生长，指数0.31，R²=0.45，p<0.005）均与成体体质量呈显著相关关系，且不受系统发育背景的影响。本研究为目前同类研究中覆盖范围最全面的一项，得以阐明次级骨单位尺寸缩放规律的整体趋势，并支持如下推论：在体型较小的哺乳动物类群中，骨单位吸收面积可能受限于避免骨骼断裂的需求；而在体型较大的哺乳动物类群中，则受限于维持骨细胞活性的需求。