# Kenyanthropus
**Kenyanthropus** is a genus of extinct hominins containing a single recognized species, *Kenyanthropus platyops*, a flat-faced, small-brained, bipedal early human that lived about 3.5 million years ago at Lomekwi, West Turkana, Kenya. It was named in 2001 by a research team led by the paleoanthropologist [Meave Leakey](https://www.edgepedia.org/meave-leakey), a National Geographic Explorer-in-Residence who directs fieldwork in the Turkana Basin, on the basis of a cranium and other fossil remains recovered in 1998 and 1999.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) The genus name means "man from Kenya," and the species name *platyops* derives from the Greek *platus*, flat, and *opsis*, face.[2](https://australian.museum/learn/science/human-evolution/kenyanthropus-platyops/)
| Key fact | Detail |
|---|---|
| Time and place | About 3.5 million years ago, West Turkana, Kenya; fossils from Lomekwi localities and the underlying Kataboi Member[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) • [3](https://link.springer.com/chapter/10.1007/978-94-007-5919-0_4) |
| Holotype | KNM-WT 40000, a mostly complete but distorted cranium found in 1999 by Justus Erus on a team led by Meave Leakey[4](https://humanorigins.si.edu/evidence/human-fossils/fossils/knm-wt-40000) |
| Naming paper | Leakey, M.G., Spoor, F., Brown, F.H., Gathogo, P.N., Kiarie, C., Leakey, L.N., and McDougall, I., 2001, *Nature* 410, 433–440[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) |
| Defining traits | Reduced subnasal prognathism, anteriorly situated zygomatic root, flat and vertically oriented malar region, relatively small but thick-enameled molars, unusually small first molar[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC3024019/) |
| Other fossils | KNM-WT 40001, a partial right temporal bone from Lomekwi 6N, and KNM-WT 8556 with a molarized fourth premolar[6](https://www.ured-douala.com/download/the_cambridge_dictionary_of_human_biology_and_evolution.pdf) • [7](https://pmc.ncbi.nlm.nih.gov/articles/PMC4988594/) |
| Diet | Carbon isotope evidence shows a very wide dietary range, from a virtually pure C3 (tree and shrub) diet to one dominated by C4 (grass and sedge) resources[8](https://pmc.ncbi.nlm.nih.gov/articles/PMC3696807/) |
| Status | Contested: some researchers treat it as a valid distinct genus and species, others as a distorted variant of *Australopithecus afarensis*[4](https://humanorigins.si.edu/evidence/human-fossils/fossils/knm-wt-40000) • [9](https://uk.sagepub.com/sites/default/files/upm-assets/7509_book_item_7509.pdf) |
## Discovery
Working in the [Lake Turkana](https://www.edgepedia.org/lake-turkana) region of northern Kenya in 1998 and 1999, Meave Leakey's team found a cranium and other fossil remains of a 3.5-million-year-old early human with a mixture of features unseen in other early human fossils, and named the new genus and species *Kenyanthropus platyops*, "flat-faced human from Kenya."[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) The holotype skull KNM-WT 40000 was found in two pieces, with the braincase separated from the face, by Justus Erus, a Kenyan research assistant on the team.[4](https://humanorigins.si.edu/evidence/human-fossils/fossils/knm-wt-40000) Renewed fieldwork at Lomekwi in 1998 and 1999 produced the species from locality LO6, with other hominin specimens from localities LO4, LO5, and LO9.[10](https://www.sciencedirect.com/science/article/abs/pii/S1040618225004215)
## Anatomy of the holotype
KNM-WT 40000 combines primitive and derived traits. Its small brain and ear canal resemble those of the very earliest humans such as *Australopithecus anamensis*, while its flat face, high cheekbones, and small, thickly enameled teeth are traits found in later human fossils such as *Homo rudolfensis* and *Homo habilis* from around 2 million years ago.[4](https://humanorigins.si.edu/evidence/human-fossils/fossils/knm-wt-40000) Leakey and colleagues did not assign the material to the contemporary *Australopithecus afarensis* because of its reduced subnasal prognathism, anteriorly situated zygomatic root, flat and vertically oriented malar region, relatively small but thick-enameled molars, and an unusually small first molar compared with the fourth premolar and third molar.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC3024019/)
The skull is badly distorted, crushed and cracked, and this preservation is central to the debate over its identity.[4](https://humanorigins.si.edu/evidence/human-fossils/fossils/knm-wt-40000) • [1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) No body fossils belonging to Kenyanthropus have been recovered, so body size cannot be estimated directly, though the skull is similar in size to those of *A. afarensis* and *A. africanus* individuals, suggesting a similar body size.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) The sex of KNM-WT 40000 is also unresolved: its small teeth resemble those of a female, but the temporal lines on the skull reflect larger chewing muscles more typical of many early human males.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops)
## Place in middle Pliocene diversity
Until Kenyanthropus was unearthed, *Australopithecus afarensis* was the sole early human species known from [East Africa](https://www.edgepedia.org/east-africa)'s 4-to-3-million-year-old fossil record.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) The naming of *K. platyops*, together with the Burtele partial foot and later *Australopithecus deyiremeda* from Ethiopia, challenged the idea of a single hominin species in the middle Pliocene and rekindled the question of hominin diversity at that time.[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC4988594/) Around 3.5 million years ago, *A. afarensis* overlapped in time with several other possible hominin taxa, including *A. bahrelghazali* in Chad, *K. platyops* in Kenya, and *A. deyiremeda* in Ethiopia.[11](https://www.sciencedirect.com/science/article/pii/S0047248416000208) Geometric morphometric shape analyses comparing the maxillae of KNM-WT 40000, the *A. deyiremeda* holotype, and other australopiths support attributing the two fossils to separate species rather than to *A. afarensis*, consistent with three contemporary hominin species in the middle Pliocene of eastern Africa.[12](https://pmc.ncbi.nlm.nih.gov/articles/PMC4920288/)
## The distortion debate
The validity of the genus rests on how the holotype's deformation is interpreted. The paleoanthropologist Tim White, of the [University of California](https://www.edgepedia.org/university-of-california), Berkeley, argued that because comparison with other fossils is made difficult by the distortion, it is impossible to differentiate Kenyanthropus from the contemporaneous *A. afarensis* and *A. anamensis*, and he opted for a conservative taxonomy that sinks Kenyanthropus into *Australopithecus*.[9](https://uk.sagepub.com/sites/default/files/upm-assets/7509_book_item_7509.pdf) The distinctive features of *K. platyops* have been ascribed by some to taphonomic distortion, the alteration of bone during burial and fossilization.[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC4988594/) The Smithsonian's Human Origins Program summarizes the two positions: the flat lower face suggests a distinct branch of the human family tree, yet some scientists think the skull offers insufficient evidence of a distinct species and that *K. platyops* is no more than a variant of *A. afarensis*; more fossils, especially an undistorted skull, are needed to resolve the question.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) • [2](https://australian.museum/learn/science/human-evolution/kenyanthropus-platyops/)
## Diet and ecology
Stable carbon isotope analysis of Turkana Basin hominin teeth shows that the later *K. platyops* had a very wide dietary range, from a virtually purely C3 resource-based diet (trees, shrubs, and their consumers) to one dominated by C4 resources (tropical grasses and sedges).[8](https://pmc.ncbi.nlm.nih.gov/articles/PMC3696807/) This breadth suggests the species expanded into a dietary niche not previously exploited by hominins in the Turkana Basin.[8](https://pmc.ncbi.nlm.nih.gov/articles/PMC3696807/) Its smaller molars compared with *A. afarensis* indicate the two species may have had different diets and likely did not compete for the same foods, though both were probably largely plant eaters.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) One unusual specimen, KNM-WT 8556, includes a molarized fourth premolar matched in size only by those attributed to the much later *Paranthropus boisei*.[7](https://pmc.ncbi.nlm.nih.gov/articles/PMC4988594/)
## Evolutionary questions
Because the only known skull was found badly distorted, many scientists hold that more fossil evidence is needed before Kenyanthropus can be placed within the human family tree.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) Some researchers note that its flat face and less-pronounced brow ridges seem more closely related to *Homo*, and the species could represent a branch closer to modern humans than Lucy's species *A. afarensis*; KNM-WT 40000 also resembles the flat-faced skull KNM-ER 1470, usually attributed to *Homo rudolfensis*, raising the question of whether *K. platyops* was that species' ancestor.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops) *K. platyops* is so far the only species assigned to the genus Kenyanthropus.[1](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops)
## References
1. [Kenyanthropus platyops, Smithsonian Institution Human Origins Program](https://humanorigins.si.edu/evidence/human-fossils/species/kenyanthropus-platyops)
2. [Kenyanthropus platyops, The Australian Museum](https://australian.museum/learn/science/human-evolution/kenyanthropus-platyops/)
3. [Reconstructing the Habitats of Australopithecus (Springer)](https://link.springer.com/chapter/10.1007/978-94-007-5919-0_4)
4. [KNM-WT 40000, Smithsonian Institution Human Origins Program](https://humanorigins.si.edu/evidence/human-fossils/fossils/knm-wt-40000)
5. [Reconstructing human evolution: Achievements, challenges, and opportunities, PNAS](https://pmc.ncbi.nlm.nih.gov/articles/PMC3024019/)
6. [The Cambridge Dictionary of Human Biology and Evolution](https://www.ured-douala.com/download/the_cambridge_dictionary_of_human_biology_and_evolution.pdf)
7. [The Pliocene hominin diversity conundrum: Do more fossils mean less clarity? PNAS](https://pmc.ncbi.nlm.nih.gov/articles/PMC4988594/)
8. [Stable isotope-based diet reconstructions of Turkana Basin hominins, PNAS](https://pmc.ncbi.nlm.nih.gov/articles/PMC3696807/)
9. [Encyclopedia entry covering Tim White's taxonomy of Kenyanthropus, SAGE](https://uk.sagepub.com/sites/default/files/upm-assets/7509_book_item_7509.pdf)
10. [The Late Pliocene to Early Pleistocene Lomekwi faunas, West Turkana, Kenya, Quaternary International](https://www.sciencedirect.com/science/article/abs/pii/S1040618225004215)
11. [Kantis: A new Australopithecus site on the shoulders of the Rift Valley near Nairobi, Kenya, Journal of Human Evolution](https://www.sciencedirect.com/science/article/pii/S0047248416000208)
12. [Middle Pliocene hominin diversity: Australopithecus deyiremeda and Kenyanthropus platyops, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC4920288/)
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*Topic: Encyclopedia › Life and health › Biological foundations › Evolution and history of life › Evolution by lineage*
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