From
https://paleoanthropology.org/ojs/index.php/paleo/article/view/1140/1087
StW 573 (“Little Foot”) Limb Functional
Anatomy and Behavioral Reconstructions,
and Their Implications for Hominin
Evolution
The ca. 3.67 Ma skeleton known as ‘Little
Foot’ (StW 573), recovered from Sterkfontein
Member 2 breccia in the Silberberg Grotto,
is remarkable for its morphology and
completeness. This adult australopith
preserves bilateral pairs of skeletal elements
in proximal and distal limb segments, making
it the earliest hominin with such an extensive
representation of the appendicular skeleton.
Cross-sectional geometric (CSG) properties
acquired from these long bone diaphyses enable
reconstruction of the loads that the individual
incurred during inferred habitual locomotor
activity. Here, we integrate investigations of
CSG properties from multiple regions of interest
(ROIs) in these elements, focusing on
evaluations of interlimb proportions and
strength-body size relationships. We compare
StW 573 values to those of extant great apes and
those of earlier, contemporary, and later
hominins to assess evolutionary trends in limb
loading. Humeral-femoral diaphyseal ROIs of
StW 573 resemble those of chimpanzees, western
lowland gorillas, and other australopiths more
than those of modern humans or other Homo taxa,
while ulnar-femoral diaphyseal ROIs corroborate
these similarities. Relatively higher strength
of the humeral and ulnar diaphyses than lower
limb diaphyses evaluated against estimated body
size suggests greater reliance on arboreal
locomotor behaviors than typical for modern
humans or fossil Homo taxa. Despite lower limb
morphologies of StW 573 that are indicative of
terrestrial bipedal gait, the CSG properties
from many limb bones clearly demonstrate that
arboreal activities also formed a selectively
advantageous part of its locomotor repertoire,
and likely earlier and contemporary hominins
as well.
--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)