Figure 1.
(a) Point cloud data for C. casuarius derived from LiDAR (light radar) scanning; (b) convex hulls of each body segment.
Table 1.
Convex hull specimen list and sources of body mass.
Table 2.
Finite element analysis specimen list and sources of body mass.
Figure 2.
Loading regimes for finite element analysis of Dinornis femur
(a) Medial view of femoral head, yellow arrows originate from the nodes to which force is applied. The direction of force is aligned parallel to the long axis of the bone, i.e. loading in compression. (b) Dorsal view of the proximal femoral epiphysis. Orange dot represents constrained control point, and is surrounded by 10 yellow dots representing the nodes to which torsion is applied via the kinematic coupling. (c) Ventral view of the distal femoral condyles. Orange squares represent nodes subject to encastre boundary conditions.
Figure 3.
(a) Dinornis robustus (S.34088/89) reconstruction of convex hulls; (b) Pachyornis australis (S.27896) (a and b are to the same scale); (c) and (d) show different positions of the sternum in D. robustus.
Figure 4.
The relationship between convex hull volume and literature values for mass in extant ratites.
LR, linear regression; SMA, standardized major axis regression; MA, major axis regression; LRO, linear regression forced through the origin.
Table 3.
Moa convex hull volumes and body segment volumes.
Table 4.
Body mass estimates of moa individuals.
Figure 5.
Finite element analysis results.
Combined compression-bending results for the femur (a) and tibiotarsus (b). Values represent maximum von Mises stress (Pa) recorded at the midshaft of the bone. Pink and blue shaded areas represent the range of stress values estimated by finite element analysis when incorporating maximum and minimum values for body mass in D. robustus and P. australis respectively. Area enclosed by dark blue box is expanded in Figure 6.
Figure 6.
(inset of Figure 5)
Combined compression-bending of the tibiotarsus between 0–20° from vertical. Values represent maximum von Mises stress (Pa) recorded at the midshaft of the bone. Legend as in figure 5.
Figure 7.
The distribution of Von Mises stress within moa finite element models.
(a) Dinornis femur loaded in compression (0° from the longest principal axis) experienced a significant degree of bending due to off-axis application of force on the femoral head. (b) Dinornis tibiotarsus experienced lower values of σvm under compression, and underwent less bending due to application of forces on the intercondylar eminence. (c) Pachyornis tibiotarsus loaded in bending (90° from the longest principal axis). σvm increases towards the fixed end of the beam, with localised areas of stress related to variations in cortical wall thickness. (d) Slice through midshaft of c. Values of σvm are highest at the extreme compressional and tensional cortices with a neutral axis of lowest stress values running between. (e) Slice through midshaft of Pachyornis femur loaded in torsion. Stress values increase radially from the endosteal to periosteal surface, with the highest stresses located in regions where cortical wall thickness is at a minimum. For (d) and (e), bone orientation is indicated by coordinate system (a–p, anteroposterior; m–l, mediolateral).
Table 5.
Finite element analysis results for torsional loading.
Table 6.
Moa body mass estimates (kg) and 95%CI based derived from palaeognath-specific regressions of femoral and tibiotarsal metrics published by Cubo and Casinos [24].