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Morphological traits that characterize the australopithecine species: Au afarensis

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Australopithecus afarensis is an australopithecine species with key morphological traits that suggest a transition to bipedalism, including prognathism and a human-like pelvis, but also has longer limbs and curved extremities indicating arboreal activities.

Step-by-step explanation:

Morphological Traits of Australopithecus afarensis

Australopithecus afarensis is a well-known australopithecine species that is characterized by several distinctive morphological traits. These traits indicate a transitional form of movement between tree-dwelling primates and bipedal humans. The most notable features include a more pronounced projection of the face, or pragmatism, and a pelvis shape more similar to that of modern humans, which suggests bipedal locomotion.

Other important morphological features of A. afarensis include:

  • Longer arms relative to modern humans, highlighting an adaptation for hanging from branches.
  • Long and curved finger and toe bones, which also suggest arboreal habits.
  • The endocranial volume of around 400 cc, akin to that of a common chimpanzee.
  • A more anteriorly positioned foramen magnum, indicating an upright posture associated with bipedal walking.

While A. afarensis showed many ape-like characteristics, especially in the limbs, the adaptations observed in the pelvis and skull signal a significant step towards bipedalism in human evolution. These traits provide evidence for a mixed mode of locomotion, combining both arboreal and ground-dwelling behaviors.

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