New single crystal
            <sup>40</sup>
            Ar/
            <sup>39</sup>
            Ar ages improve time scale for deposition of the Omo Group, Omo–Turkana Basin, East Africa

McDougall, Ian; Brown, Francis H.; Vasconcelos, Paulo M.; Cohen, B. E.; Thiede, David S.; Buchanan, Michael J.

doi:10.1144/0016-76492010-188

Cited by 150 publications

(115 citation statements)

References 36 publications

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“…10 y before death for these individuals. Age estimates for each hominin use the correlations and chronology of the >350 volcanic ashes in the basin (20)(21)(22)(23)64); taxonomic assignments are in refs. 24 and 25.…”

Section: Methodsmentioning

confidence: 99%

Stable isotope-based diet reconstructions of Turkana Basin hominins

Cerling

Manthi

Mbua

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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184

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Hominin fossil evidence in the Turkana Basin in Kenya from ca . 4.1 to 1.4 Ma samples two archaic early hominin genera and records some of the early evolutionary history of Paranthropus and Homo . Stable carbon isotopes in fossil tooth enamel are used to estimate the fraction of diet derived from C 3 or C 4 resources in these hominin taxa. The earliest hominin species in the Turkana Basin, Australopithecus anamensis , derived nearly all of its diet from C 3 resources. Subsequently, by ca . 3.3 Ma, the later Kenyanthropus platyops had a very wide dietary range—from virtually a purely C 3 resource-based diet to one dominated by C 4 resources. By ca . 2 Ma, hominins in the Turkana Basin had split into two distinct groups: specimens attributable to the genus Homo provide evidence for a diet with a ca . 65/35 ratio of C 3 - to C 4 -based resources, whereas P. boisei had a higher fraction of C 4 -based diet ( ca . 25/75 ratio). Homo sp. increased the fraction of C 4 -based resources in the diet through ca . 1.5 Ma, whereas P. boisei maintained its high dependency on C 4 -derived resources.

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Section: Methodsmentioning

confidence: 99%

Stable isotope-based diet reconstructions of Turkana Basin hominins

Cerling

Manthi

Mbua

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

184

178

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“…13 C values in the Shungura bovid, suid and hippopotamid studied became more enriched by an average þ4‰ between units B-10 and C-4/C-5, or sometime between 2.97 Ma and just under 2.74 Ma (figures 1 and 2) [7]. d …”

Section: Enamel Dmentioning

confidence: 92%

Ecological change in the lower Omo Valley around 2.8 Ma

et al. 2013

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Late Pliocene climate changes have long been implicated in environmental changes and mammalian evolution in Africa, but high-resolution examinations of the fossil and climatic records have been hampered by poor sampling. By using fossils from the well-dated Shungura Formation (lower Omo Valley, northern Turkana Basin, southern Ethiopia), we investigate palaeodietary changes in one bovid and in one suid lineage from 3 to 2 Ma using stable isotope analysis of tooth enamel. Results show unexpectedly large increases in C 4 dietary intake around 2.8 Ma in both the bovid and suid, and possibly in a previously reported hippopotamid species. Enamel d 13 C values after 2.8 Ma in the bovid (Tragelaphus nakuae) are higher than recorded for any living tragelaphin, and are not expected given its conservative dental morphology. A shift towards increased C 4 feeding at 2.8 Ma in the suid (Kolpochoerus limnetes) appears similarly decoupled from a well-documented record of dental evolution indicating gradual and progressive dietary change. The fact that two, perhaps three, disparate Pliocene herbivore lineages exhibit similar, and contemporaneous changes in dietary behaviour suggests a common environmental driver. Local and regional pollen, palaeosol and faunal records indicate increased aridity but no corresponding large and rapid expansion of grasslands in the Turkana Basin at 2.8 Ma. Our results provide new evidence supporting ecological change in the eastern African record around 2.8 Ma, but raise questions about the resolution at which different ecological proxies may be comparable, the correlation of vegetation and faunal change, and the interpretation of low d 13C values in the African Pliocene.

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“…6 Cranium KNM-ER 3733 (discovered in 1975), from the lower part of the KBS Member of the Koobi Fora Formation at East Turkana, has exemplified the best and oldest evidence for a third cranial morph-attributed to early Homo erectus (or H. ergaster by some)-in eastern Africa [50,60,61]. Recent refinement in the age framework for the KBS Member has pushed up the age estimate for this specimen from as old as 1.78 to 1.7-1.6 Ma [62,63], which makes it approximately contemporary with Homo habilis in upper Bed I and lower Bed II at Olduvai Gorge. KNM-ER 2598, an occipital bone unmistakably H. erectus-like in its greatly thickened, strongly flexed squama surmounted by a prominent occipital torus ( [61] and figure 4), now stands as potentially the earliest evidence for H. erectus in Africa at approximately 1.9 Ma, approximately contemporary with KNM-ER 1470 and KNM-ER 1813.…”

Section: The Changing Idea Of Early Homomentioning

confidence: 93%

From Australopithecus to Homo : the transition that wasn't

Kimbel

Villmoare

2016

Phil. Trans. R. Soc. B

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One contribution of 17 to a discussion meeting issue 'Major transitions in human evolution'. Although the transition from Australopithecus to Homo is usually thought of as a momentous transformation, the fossil record bearing on the origin and earliest evolution of Homo is virtually undocumented. As a result, the poles of the transition are frequently attached to taxa (e.g. A. afarensis, at ca 3.0 Ma versus H. habilis or H. erectus, at ca 2.0-1.7 Ma) in which substantial adaptive differences have accumulated over significant spans of independent evolution. Such comparisons, in which temporally remote and adaptively divergent species are used to identify a 'transition', lend credence to the idea that genera should be conceived at once as monophyletic clades and adaptively unified grades. However, when the problem is recast in terms of lineages, rather than taxa per se, the adaptive criterion becomes a problem of subjectively privileging 'key' characteristics from what is typically a stepwise pattern of acquisition of novel characters beginning in the basal representatives of a clade. This is the pattern inferred for species usually included in early Homo, including H. erectus, which has often been cast in the role as earliest humanlike hominin. A fresh look at brain size, hand morphology and earliest technology suggests that a number of key Homo attributes may already be present in generalized species of Australopithecus, and that adaptive distinctions in Homo are simply amplifications or extensions of ancient hominin trends.This article is part of the themed issue 'Major transitions in human evolution'.Whether primeval man, when he possessed very few arts of the rudest kind, and when his power of language was extremely imperfect, would have deserved to be called man, must depend on the definition which we employ. In a series of forms graduating insensibly from some ape-like creature to man as he now exists it would be impossible to fix on any definite point when the term 'man' ought to be used.-Charles Darwin [2, p. 235] The descent of man, and selection in relation to sex.It seems to me more likely that H[omo] habilis and H. erectus, as well as some of the australopithecines, were all evolving along their own distinct lines by Lower Pleistocene times. This would mean that their shared common ancestor must be sought in the more remote past and that when such examples of the parent stock are found they will not much resemble any one of the three subsequent branches.-Louis Leakey [3, p. 1280] 'Homo habilis, Homo erectus and the australopithecines'.

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New single crystal ⁴⁰ Ar/ ³⁹ Ar ages improve time scale for deposition of the Omo Group, Omo–Turkana Basin, East Africa

Cited by 150 publications

References 36 publications

Stable isotope-based diet reconstructions of Turkana Basin hominins

Stable isotope-based diet reconstructions of Turkana Basin hominins

Ecological change in the lower Omo Valley around 2.8 Ma

From Australopithecus to Homo : the transition that wasn't

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New single crystal 40 Ar/ 39 Ar ages improve time scale for deposition of the Omo Group, Omo–Turkana Basin, East Africa

Cited by 150 publications

References 36 publications

Stable isotope-based diet reconstructions of Turkana Basin hominins

Stable isotope-based diet reconstructions of Turkana Basin hominins

Ecological change in the lower Omo Valley around 2.8 Ma

From Australopithecus to Homo : the transition that wasn't

Contact Info

Product

Resources

About

New single crystal ⁴⁰ Ar/ ³⁹ Ar ages improve time scale for deposition of the Omo Group, Omo–Turkana Basin, East Africa