Omo Kibish Formation

Coordinates: 4°48′1.27″N 35°58′1.45″E / 4.8003528°N 35.9670694°E / 4.8003528; 35.9670694
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Omo Kibish Formation rocks near the town of Kibish, where the human fossils were discovered

The Omo Kibish Formation or simply Kibish Formation is a

Homo sapiens. Known as Omo Kibish 1 (Omo I), the fossil was dated to 196 ± 5 ka old and is among two other Omo remains (Omo II and Omo III) that were found in Member I.[3] The Omo fossils were more recently (in 2022) re-dated to approximately 233 ± 22 ka old.[4] In the early 2000s a research boom enriched the knowledge base about the Kibish Formation. Study of the faunal remains (large mammal and fish faunas) and stone tools provided insight into the archeological associations of Homo sapiens and thereby their behaviors and the complex environmental contexts in which they lived and evolved.[5][6][7]

MSA Lithic assemblage

During Richard Leakey's original 1967 excavations several stone tools were found in association with Omo 1 at Kamoya's hominid site (KHS)  but were not well described in the research literature. In the 2000s further excavations occurred at KHS in addition to two other sites: Awoke's hominid site (AHS) also located in Member 1 and the Bird's Nest Site (BNS)  located in Member 2. Summaries of the lithic assemblages found during the more recent excavations also consider the lithics found in the initial 1967 excavation.[5]

The most common material used to produce the lithics found is chert. In general high quality fine-grained cryptocrystalline silicate raw materials such as jasper, chert, chalcedony comprise the clear majority (60-90% ) across all sites. Given that all but one rare occurring material could be found in cotemporary gravel deposits in Member 1, it is predicted that early hominins obtained the necessary rock

assemblages the cores were particularly small. However, it was hypothesized that this was a likely result of starting from smaller clasts. Despite such differences, paleoanthropologist John Shea concludes that the Kibish Industry seems to be a local variant of the larger east African industry yet to be named.[5]

Faunal remains

Large-mammal fauna

Research by Assefa et al. sampled all members but obtained faunal remains from only Members I, III, and IV. The faunal assemblages obtained from each member are similar in their diversity of mammals and  are largely representative of the large mammals which comprise the current community of fauna in the area. That is, predominantly

Equus burchellii and E. grevyi because this may suggests that the Omo Kibish area has for a long time been an exception to the otherwise rare coexistence of the two species in a given habitat. It is predicted that inadequate sample size rather than the existence of only current fauna during the late- middle Pleistocene  may explain the absence of any extinct species within the Kibish Formation.[6]

Fish fauna

Taxonomic Composition

In total, 337 skeletal specimens of fish were collected from the Kibish formation members; as in the case of the mammals, fossils were found only in members I,III and IV. Although some of the 337 specimens likely belonged to the  same individuals, it is believed that summaries of the taxonomic frequencies is not greatly impacted by this fact.[7]

Together perciforms and siluriforms (catfish) comprise a staggering 86.7 percent of the Kibish assemblage. Importantly, the order perciform is represented entirely by a single species (Lates niloticus) while 76 percent of siluriforms are represented by Synodontis and clariids. Although the Kibish ichthyofauna does not closely approximate the documented biodiversity of the extant community (9 out of the 37 known genera were identified), overall it is similar to the modern fauna in the region. Member III contained all nine genera while Member I was missing  Hydrocynus and Schilbe; nonetheless the two members were similar in the taxonomic frequencies (by order). Member IV contained only the three predominant genera ( Lates, Synodontis and Clarias).[7]

Hominid Interaction

Although there are no suggestive markings on the fossil material itself, other lines of evidence suggest that fishing was an established  method of subsistence for hominids occupying the Omo Turkana Basin. The main evidence includes barbed bone points, similar to those in other MSA sites, found in Member IV. In said MSA sites in eastern and southern Africa, these bone points were found in association with processed fish material. Moreover, characteristics of some of the Kibish taxa, such as their large size or preference for open waters habitats suggest that they would indeed require tools to be procured.[7]

See also

References

  1. ISSN 0031-0182
    .
  2. S2CID 226102439
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  3. PMID 18617219
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  4. PMID 35022610
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  5. ^
    PMID 18691735
    .
  6. ^
    S2CID 5923387
    .
  7. ^
    PMID 18691738
    .

4°48′1.27″N 35°58′1.45″E / 4.8003528°N 35.9670694°E / 4.8003528; 35.9670694

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