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For much of the Pliocene and Pleistocene, multiple hominin species coexisted in the same regions of eastern and southern Africa. Due to the limitations of the skeletal fossil record, questions regarding their interspecific interactions remain unanswered. We report the discovery of footprints (~1.5 million years old) from Koobi Fora, Kenya, that provide the first evidence of two different patterns of Pleistocene hominin bipedalism appearing on the same footprint surface. New analyses show that this is observed repeatedly across multiple contemporaneous sites in the eastern Turkana Basin. These data indicate a sympatric relationship betweenHomo erectusandParanthropus boisei, suggesting that lake margin habitats were important to both species and highlighting the possible influence of varying levels of coexistence, competition, and niche partitioning in human evolution.
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Monkeys in the Middle: Modeling ecological flexibility and niche construction in African cercopithecid primates
Niche construction is broadly defined as an organism’s influence over its environment, ranging from the depletion of local resources to the intentional modification of landscapes and ecosystems. While modern humans excel at the latter, the exact timing and nature of our transition to being complex cultural niche constructors remains to be determined. Here I use methods taken from community ecology to develop a baseline model of minimal niche construction within a group of primate generalists. This serves as an important comparison for interpretations of the hominin fossil record and broader paleontological record to determine when and how our hominin ancestors began to diverge from this pattern. Dental metric data were used in principal components analysis to reconstruct the dietary ecomorphological niches of a sample African cercopithecid primates from the Plio-Pleistocene to today. Potential niche construction is identified through the displacement of co-occurring species indicating that the focal taxon has excluded potential competitors through resource depletion. Overall, fossil taxa are shown to occupy a more restricted niche than their extant relatives, but otherwise exhibit similar patterns of dispersion and overlap within and across communities. The lack of consistent trends within the Plio-Pleistocene sample — either through time or in response to potential confamilial competition — supports the idea that these generalized primates are not exerting a significant influence over their local environments. I conclude with some suggestions on expanding these analyses to look for evidence of niche construction in other paleontological and paleoanthropological contexts.
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- Award ID(s):
- 1926163
- PAR ID:
- 10172350
- Date Published:
- Journal Name:
- Program of the Annual Meeting of the American Association of Physical Anthropologists
- Volume:
- 171
- Issue:
- S69
- ISSN:
- 2331-1355
- Page Range / eLocation ID:
- 264-265
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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null (Ed.)Fossil cercopithecid primates of the African Plio-Pleistocene are often found together in fossil deposits across East and South Africa. These species may have co-occurred in life and exploited similar types of resources in shared environments, as extant monkeys in Africa and Asia are known to do. Some of these fossil species are represented today by congeneric or descendant species with similar adaptations while others have no modern analogue. This project uses dental morphology to compare community structure across potentially co-occurring fossil and modern cercopithecid populations (the cercopithecid taxocene). Relative enamel thickness, shearing potential, and dental shape ratios from the P4 – M3 toothrow were measured from extant (n > 700) and fossil cercopithecid specimens (n > 1000). The latter primarily targeted the Hadar, Shungura, and Koobi Fora Formations of East Africa and the sites of Makapansgat, Sterkfontein, and Swartkrans in South Africa. Principal component analyses were performed separately on the maxillary and mandibular dentitions and resulting component scores were used to reconstruct the taxocene dental morphology at each site. In general, the African cercopithecid taxocene is similar across the main fossil sites analyzed. Patterns of overlap between fossil and modern sites may reflect environmental similarities or the adaptability of generalist cercopithecids. An apparent niche shift from the Plio-Pleistocene to today reflects both taphonomic and ecological factors: a lack of smaller-bodied fossil cercopithecin and colobine species combined with an expanded dental ecomorphological niche of larger-bodied fossil species.more » « less
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