Electronic supporting information for: Evolution of posture in amniotes–diving into the trabecular architecture of the femoral head
Data files
Nov 08, 2023 version files 963.11 MB
Abstract
Extant amniotes show remarkable postural diversity. Broadly speaking, limbs with erect (strongly adducted, more vertically oriented) posture are found in mammals that are particularly heavy (graviportal) or show good running skills (cursorial), while crouched (highly flexed) limbs are found in taxa with more generalized locomotion. In Reptilia, crocodylians have a “semi-erect” (somewhat adducted) posture, birds have more crouched limbs and lepidosaurs have sprawling (well-abducted) limbs. Both synapsids and reptiles underwent a postural transition from sprawling to more erect limbs during the Mesozoic Era. In Reptilia, this postural change is prominent among archosauriforms in the Triassic Period. However, limb posture in many key Triassic taxa remains poorly known. In Synapsida, the chronology of this transition is less clear, and competing hypotheses exist. On land, the limb bones are subject to various stresses related to body support that partly shape their external and internal morphology. Indeed, bone trabeculae (lattice-like bony struts that form the spongy bone tissue) tend to orient themselves along lines of force. Here, we study the link between femoral posture and the femoral trabecular architecture using phylogenetic generalized least squares. We show that microanatomical parameters measured on bone cubes extracted from the femoral head of a sample of amniote femora depend strongly on body mass, but not on femoral posture or lifestyle. We reconstruct ancestral states of femoral posture and various microanatomical parameters to study the “sprawling-to-erect” transition in reptiles and synapsids, and obtain conflicting results. We tentatively infer femoral posture in several hypothetical ancestors using phylogenetic flexible discriminant analysis from maximum likelihood estimates of the microanatomical parameters. In general, the trabecular network of the femoral head is not a good indicator of femoral posture. However, ancestral state reconstruction methods hold great promise for advancing our understanding of the evolution of posture in amniotes.
README: Gônet et al. Evolution of posture in amniotes–Diving into the trabecular architecture of the femoral head. Electronic supporting information.
This dataset contains the information files that support the results presented in the study by Gônet, J., Laurin, M., & Hutchinson, J. R.
Description of the data and file structure
The file entitled Phylogenetic_Trees.tre contains the 100 phylogenetic trees used in the study. The trees are in Newick (parenthetic) format. The file can be opened and modified as a .txt file, but is intended for use in R as part of the analyses presented in the study.
The file entitled Supporting_Information.pdf contains the supplementary figures and tables mentioned in the main text of the study.
The file entitled Bone_Cubes.rar contains the new microanatomical data obtained to complement the original data from Doube et al. (2011). The archive contains 25 folders corresponding to the 25 amniote species studied for which new microanatomical data are available. These are provided as .tif files. The name of each folder is determined as follows: Genus_species_identifier.