Is Australopithecus Afarensis Evidence of Hominid Evolution?

Australopithecus afarensis. There is no consensus among paleoanthropologists as to whether or not A. afarensis had ability to do knuckle-walking, or even if A. afarensis was largely bipedal. There is still an on-going tug of war between 2 schools of thought as to how fossils alleged to be afarensis should be interpreted for whatever abilities/physical features are allegedly evidenced by any particular skeletal reconstruction involving certain fossils.

It is said that afarensis' femur angles in toward the knee from the hip, and that is said to be a strong indication of habitual bipedal locomotion; however, it is also said that along with humans, present day orangutans and spider monkeys possess this same feature.

Also questionable is whether Australopithecus foot bones indicate the Laetoli footprints were even made by Australopithecus. "Many scientists also doubt the suggestion of bipedalism, and argue that even if Australopithecus really did walk on two legs, it did not walk in the same way as humans . . . The shoulder joint is also oriented much more cranially (i.e. towards the skull) than that in modern humans but similar to that in the present day apes. Combined with the relatively long arms A. afarensis is thought to have had, this is thought by many to be reflective of a heightened ability to use the arm above the head in climbing behaviour. Furthermore, scans of the skulls reveal a canal and bony labyrinth morphology, which is not supportive to proper bipedal locomotion."

Also is this admission: "In particular the morphology of scapula appears to be ape-like and very different from modern humans. The curvature of the finger and toe bones (phalanges) approaches that of modern-day apes, and is suggestive of their ability to efficiently grasp branches and climb."

Also disputed is whether or not all the fossils labeled A. afarensis belong just to that one species, but that there is a mix in the Hadar site's fossils, representing more than one species.

Also, there is this as reviewed in Science 26 October 2012: "Scapular morphology is predictive of locomotor adaptations among primates, but this skeletal element is scarce in the hominin fossil record. Notably, both scapulae of the juvenile Australopithecus afarensis skeleton from Dikika, Ethiopia, have been recovered. These scapulae display several traits characteristic of suspensory apes, as do the few known fragmentary adult australopith representatives. Many of these traits change significantly throughout modern human ontogeny, but remain stable in apes. Thus, the similarity of juvenile and adult fossil morphologies implies that A. afarensis development was apelike. Additionally, changes in other scapular traits throughout African ape development are associated with shifts in locomotor behavior. This affirms the functional relevance of those characteristics, and their presence in australopith fossils supports the hypothesis that their locomotor repertoire included a substantial amount of climbing."

Also, Susman and Stern said: "She [afarensis] probably nested in the trees and lived like other monkeys."

Also, Charles Oxnard performed a multivariate analysis on afarensis and concluded that it is truly unique: "The various australopithecines are, indeed, more different from both African apes and humans in most features than these latter are from each other."

Also, about "[an] exceptionally well-preserved skeleton of an A. afarensis child from Dikika, Ethiopia, discovered in 2000 by Dr. Alemseged . . . further preparation and extensive analyses of these rare bones showed them to be quite apelike, suggesting that this species was adapted to climbing trees in addition to walking bipedally when on the ground. "The question as to whether Australopithecus afarensis was strictly bipedal or if they also climbed trees has been intensely debated for more than thirty years," said Dr. Green. These remarkable fossils provide strong evidence that these individuals were still climbing at this stage in human evolution." The new findings are published in the October 26 issue of the journal Science.

Mexican Fossilized Impressions - 20,000 Years Old; or 40,000 Years Old; or 1,300,000 Years Old?

Ancient Human Footprints Found in Mexico | Science/AAAS. Geochronological analyses assign wildly divergent dates (20 kyr-1myr) to the fossilized impression. Why? Need there be more fossilized impressions uncovered in rocky outcrops there -- undisturbed by modern-day vehicular traffic -- before science can resolve the disputed claims? Is there an even playing field for studies of the Mexican and African fossils?

There is dispute not only as to the age of the impressions, but also as to whether or not the fossilized impressions are even human footprints. What are alleged to be human footprints occur in what appears to be a pattern for bipedal locomotion, and occur among a plethora of other animal footprints. The dates assigned the fossilized footprints range from 20,000 years old to 1,300,000 years old ! Tim White, who has used the Berkeley lab for dating African fossils, has no doubt that the Berkeley lab has given correct date of about 1.3 million years old; accordingly, he must dispute the human identification that other scientists give the maker of the fossilized impressions. See
http://www.berkeley.edu/news/media/releases/2005/11/30_fp.shtml