Palaeoenvironments and hominoid evolution

Area of Science:

• Paleoanthropology
• Evolutionary Biology
• Primatology

Background:

• Obligate bipedal locomotion is a defining trait of hominids (Homo, Praeanthropus, Australopithecus, Paranthropus), differentiating them from quadrupedal hominoids (Pan, Gorilla, Pongo).
• Fossil record scarcity between 15 Ma and 4.2 Ma presents a challenge in understanding the origins of hominid bipedalism.

Purpose of the Study:

• To investigate the evolutionary pressures and environmental context surrounding the emergence of bipedal locomotion in early hominids.
• To correlate the evolution of bipedalism with significant faunal and environmental changes in Africa during the late Miocene.

Main Methods:

• Analysis of Old World geology and paleontology to reconstruct paleoenvironments and faunal changes.
• Comparative analysis of locomotion and dietary adaptations between hominids and other hominoids.

Main Results:

• A significant faunal turnover occurred in Africa towards the end of the Miocene, favoring 'modern' lineages adapted to open habitats over 'archaic' ones.
• Hominoids adapted to open environments likely increased foraging ranges, creating selective pressure for locomotor modification (bipedalism) rather than dietary changes.
• The emergence of bipedal hominids is hypothesized to have occurred during this period of faunal reorganization, potentially dating the family Hominidae (sensu stricto) to 8-7 Ma.

Conclusions:

• Hominid bipedalism likely evolved in response to late Miocene environmental shifts and associated changes in foraging strategies.
• The study posits a link between ecological pressures and the unique locomotor adaptation defining the human lineage.