To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This chapter explores upper limb adaptation in Australopithecus afarensis in order to identify possible adaptations to behaviours other than arboreality. Limb length proportions and elbow articular morphology suggest that the upper limb of A. afarensis does not display a morphology that implies strong directional, or even stabilising selection, for arboreality. On the other hand, many traits suggest that A. afarensis adapted to use of the upper limbs for manipulation. The species had no carpometacarpal ligament between the second metacarpal and the capitate, a curved and more proximally oriented second metacarpal-capitate articular surface, and a more coronally and transversally oriented trapezio-second metacarpal facet. All these traits allow for rotation of the second metacarpal during manipulation. In addition, the second and third metacarpal heads of A. afarensis are tapered with a marked asymmetry in distal view. In palmar view, the articular facet of the A. afarensis second metacarpal is also asymmetrical, with the radial size projecting more proximally and palmarly than the ulnar side. This results in pronation of the second finger during flexion, which allows the finger to conform to the shape of the manipulated object. Again, this list of traits is found only in humans among extant hominoids. Other traits such as a relatively longer thumb and a proximally oriented olecranon also suggest that A. afarensis had adapted to manipulatory activities. The absence of archaeological sites contemporaneous with A. afarensis may be due to various factors, such as the use of perishable material, the absence of a home base or of foraging route standardisation, and so forth. In conclusion, it is not possible to positively demonstrate that A. afarensis made or used tools without finding fossil remains in association with tools, but their morphology is consistent with the finger dexterity and the positioning of hands close to the body that are part of toolmaking and tool-using activities, a novel behaviour for hominins. If A. afarensis was still indeed a habitual arboreal animal, its upper limbs show a compromise for this novel behaviour that was extremely important and that, perhaps, was made possible by the adoption of bipedal stance.