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Microanatomical Record of Cortical Bone Remodeling and High Vascularity in a Fossil Giant Rat Midshaft Femur
Author(s) -
Miszkiewicz Justyna J.,
Louys Julien,
O'Connor Sue
Publication year - 2019
Publication title -
the anatomical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.678
H-Index - 62
eISSN - 1932-8494
pISSN - 1932-8486
DOI - 10.1002/ar.24224
Subject(s) - vascularity , anatomy , femur , cortical bone , biology , histology , cortex (anatomy) , bone remodeling , long bone , pathology , medicine , paleontology , neuroscience , genetics
Rat cortical bone does not typically undergo secondary (Haversian) remodeling. Haversian organization of rat bone has been mainly observed in experimental settings following biomechanical or dietary manipulation. Here, we report an observation of cortical secondary osteons within a histological femur cross‐section from an extinct (late Quaternary) form of Timorese giant rat (Murinae gen. et sp. indet). The medio‐lateral midshaft diameter of its femur, used as a measure of bone size, is 6.15 mm and indicates a heavier than normal skeletal frame. We compare this sample to bone histology in a small rat's midshaft femur of 2.33 mm diameter. A complete lack of Haversian bone remodeling characteristics is noted for the smaller sample, which is dominated by radial vascular canals. The giant rat shows clear secondary osteons and diffuse vascularity mainly composed of tightly packed longitudinal canals across its cortex. It appears that rat cortical bone can undergo bone remodeling, and is organized in a highly vascularized manner, in insular giant cases. Our findings from Timor align with results reported in experimental rat model skeletal biology literature and other insular fossil rat material. Where macroanatomical examination is limited, histological observations on fossil rat limb bones have the potential to aid reconstructions of life history and skeletal growth aspects in these rodents. Anat Rec, 302:1934–1940, 2019. © 2019 American Association for Anatomy