1
|
Lewis JE, Ward CV, Kimbel WH, Kidney CL, Brown FH, Quinn RL, Rowan J, Lazagabaster IA, Sanders WJ, Leakey MG, Leakey LN. A 4.3-million-year-old Australopithecus anamensis mandible from Ileret, East Turkana, Kenya, and its paleoenvironmental context. J Hum Evol 2024; 194:103579. [PMID: 39173445 DOI: 10.1016/j.jhevol.2024.103579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 07/26/2024] [Accepted: 07/27/2024] [Indexed: 08/24/2024]
Abstract
A hominin mandible, KNM-ER 63000, and associated vertebrate remains were recovered in 2011 from Area 40 in East Turkana, Kenya. Tephrostratigraphic and magnetostratigraphic analyses indicate that these fossils date to ∼4.3 Ma. KNM-ER 63000 consists of articulating but worn and weathered mandibular corpora, with a broken right M2 crown and alveoli preserved at other tooth positions. Despite extensive damage, KNM-ER 63000 preserves diagnostic anatomy permitting attribution to Australopithecus anamensis. It can be distinguished from Australopithecus afarensis by its strongly inclined symphyseal axis with a basally convex, 'cut-away' external surface, a lateral corpus that sweeps inferomedially beneath the canine-premolar row, and alignment of the canine alveolus with the postcanine axis. KNM-ER 63000 is distinguished from Ardipithecus ramidus by its thick mandibular corpus and large M2 crown. The functional trait structure and enamel's stable carbon isotopic composition of the Area 40 large-mammal community suggests an environment comparable to Kanapoi and other ∼4.5-4 Ma eastern African sites that would have offered Au. anamensis access to both C3 and C4 food resources. With an age of ∼4.3 Ma, KNM-ER 63000 is the oldest known specimen of Au. anamensis, predating the Kanapoi and Asa Issie samples by at least ∼100 kyr. This specimen extends the known temporal range of Au. anamensis and places it in temporal overlap with fossils of Ar. ramidus from Gona, Ethiopia. The morphology of KNM-ER 63000 indicates that the reconfigured masticatory system differentiating basal hominins from the earliest australopiths existed in the narrow temporal window, if any, separating the two. The very close temporal juxtaposition of these significant morphological and adaptive differences implies that Ar. ramidus was a relative rather than a direct phyletic ancestor of earliest Australopithecus.
Collapse
Affiliation(s)
- Jason E Lewis
- Turkana Basin Institute, Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Chronicle Heritage, 319 E Palm Lane, Phoenix, AZ 85004, USA
| | - Carol V Ward
- Department of Pathology & Anatomical Sciences, University of Missouri, Columbia, MO 65212, USA.
| | - William H Kimbel
- Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287-4101, USA
| | - Casey L Kidney
- Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-0112, USA
| | - Frank H Brown
- Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-0112, USA
| | - Rhonda L Quinn
- School of Earth, Environment & Society, Bowling Green State University, Bowling Green, OH 43403-0085, USA
| | - John Rowan
- Department of Archaeology, University of Cambridge, Cambridge, UK
| | - Ignacio A Lazagabaster
- National Research Center on Human Evolution (CENIEH), Paseo Sierra de Atapuerca 3, Burgos 09002, Spain; Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool L69 3BX, UK
| | - William J Sanders
- Museum of Paleontology, University of Michigan, Ann Arbor, MI 48109-1085, USA
| | - Meave G Leakey
- Turkana Basin Institute, Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - Louise N Leakey
- Turkana Basin Institute, Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA; Department of Paleontology, National Museums of Kenya, Museum Hill, Nairobi, Kenya
| |
Collapse
|
2
|
Fillion EN, Harrison T. Hominin turnover at Laetoli is associated with vegetation change: Multiproxy evidence from the large herbivore community. J Hum Evol 2024; 191:103546. [PMID: 38795630 DOI: 10.1016/j.jhevol.2024.103546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/28/2024]
Abstract
Vegetation change in eastern Africa during the Pliocene would have had an important impact on hominin adaptation and ecology, and it may have been a key driver of hominin macroevolution, including the extinction of Australopithecus and the emergence of Paranthropus and Homo. The Pliocene paleoanthropological site of Laetoli in Tanzania provides an opportunity to investigate the relationship between vegetation change and hominin turnover because it encompasses the time period when grass cover was spreading across eastern Africa and because hominin species turnover occurred locally at Laetoli, with Paranthropus aethiopicus in the Upper Ndolanya Beds (UNB) replacing Australopithecus afarensis in the Upper Laetolil Beds (ULB). However, it remains unresolved how the vegetation of the UNB and the ULB differed from each other. To examine differences between the two stratigraphic units, multiple proxies-hypsodonty, mesowear, and stable carbon isotopes of tooth enamel (δ13Cenamel)-are used to infer the diets of large herbivores and compare the dietary guild structure of the large herbivore communities. All three proxies indicate an increase in the abrasiveness and C4-content in the diets of the large herbivores in the UNB relative to those in the ULB. After inferring the diets of species based on all three proxies, the large herbivore community of the UNB had a greater proportion of grazers and a smaller proportion of mixed feeders than in the ULB but maintained a similar proportion of browsers and frugivores. The ULB community has few modern-day analogs, whereas the UNB community is most closely analogous to those in modern African grasslands. Thus, hominin turnover at Laetoli is associated with an increase in grass cover within a woodland-grassland mosaic and is part of a broader transformation of the herbivore community structure.
Collapse
Affiliation(s)
- Elizabeth N Fillion
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA.
| | - Terry Harrison
- Center for the Study of Human Origins, Department of Anthropology, New York University, 25 Waverly Pl., New York, NY, 10003, USA; New York Consortium in Evolutionary Primatology, New York, NY, 10024, USA
| |
Collapse
|
3
|
Reda HG, Frost SR, Simons EA, Quade J, Simpson SW. Description and taxonomic assessment of fossil Cercopithecidae from the Pliocene Galili Formation (Ethiopia). J Hum Evol 2024; 190:103508. [PMID: 38599140 DOI: 10.1016/j.jhevol.2024.103508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 04/12/2024]
Abstract
The Mount Galili Formation in the Afar region, Ethiopia, samples a critical time in hominin evolution, 4.4 to 3.8 Ma, documenting the last appearance of Ardipithecus and the origin of Australopithecus. This period is also important in the evolution of cercopithecids, especially the origin of Theropithecus in general and Theropithecus oswaldi lineage in particular. Galili has provided a total of 655 cercopithecid specimens that include crania, mandibles, isolated teeth and postcrania. All the fossils were recovered from the Lasdanan (5.3-4.43 Ma), Dhidinley (4.43-3.9 Ma) and Shabeley Laag (∼3.92-3.8 Ma) Members. Here, we described and analyzed 362 fossils employing both qualitative and quantitative methods. Descriptions of the material were supplemented with dental metrics and cranial shape analysis using three-dimensional geometric morphometrics. Results indicate the presence of at least six cercopithecid taxa: Theropithecus oswaldi serengetensis (n = 28), Theropithecus sp. (n = 2), three non-Theropithecus papionin groups (n = 134) and one colobine-size group (n = 58). The T. o. serengetensis represents the earliest form of the lineage, documented from ∼3.9 Ma Galili sediments. The three Galili papionins include a smaller taxon, a medium-sized taxon comparable to Pliopapio alemui and a large papionin overlapping in size with Soromandrillus, Gorgopithecus and Dinopithecus. The majority of Galili colobines have closest affinities to Kuseracolobus aramisi and some overlap with other taxa. Papionins dominate the Galili cercopithecid collection, although colobines are still fairly common (approximately 25% of the sample). Thus, Galili sample is like Kanapoi (4.2-4.1 Ma) and Gona (5.2-3.9 Ma) localities but distinct from Aramis, suggesting paleoecological similarity to the former sites. On the other hand, Theropithecus is less abundant at Galili than geologically younger Hadar (3.4-3.2 Ma) and Woranso-Mille (3.8-3.6 Ma) sites. Whether this difference is due to sampling, time or landscape variation requires further investigation.
Collapse
Affiliation(s)
- Hailay G Reda
- Department of Anthropology, University of Oregon, Eugene, OR, 97403-1218, USA.
| | - Stephen R Frost
- Department of Anthropology, University of Oregon, Eugene, OR, 97403-1218, USA
| | - Evan A Simons
- Department of Behavioral Neuroscience, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, L470, Portland, OR, 97239, USA
| | - Jay Quade
- Department of Geosciences, University of Arizona, 1040 E. 4th Street, Tucson, AZ, 85721, USA
| | - Scott W Simpson
- Department of Anatomy, Case Western Reserve University, Cleveland, OH, 44106-4930, USA; Laboratory of Physical Anthropology, Cleveland Museum of Natural History, Cleveland, OH, 44106, USA
| |
Collapse
|
4
|
Wynn JG, Dumouchel L, Drapeau MSM. Paleoenvironments represented by the sediments of the Early Pliocene Mursi Formation, Omo Valley, Ethiopia. J Hum Evol 2023; 181:103410. [PMID: 37454604 DOI: 10.1016/j.jhevol.2023.103410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 06/10/2023] [Accepted: 06/10/2023] [Indexed: 07/18/2023]
Abstract
While our understanding of human origins has been enriched by extensive efforts to reconstruct the ancient environmental context of early hominins using information from hominin-bearing localities, comparatively little effort has been focused on contemporaneous fossil localities with abundant vertebrate fossils, but lacking hominins. We report here on new paleoenvironmental reconstructions of the Mursi Formation, Ethiopia, from which strata dated to >4 Ma preserve an abundant vertebrate fossil record lacking any known hominins, despite being part of a contiguous sedimentary basin known for its rich hominin fossil record. We combine new stratigraphic and sedimentological observations with data from paleosols preserved in the sedimentary sequence, along with isotopic data from pedogenic carbonate, paleosol organic matter, and sulfur minerals preserved in the sediments (gypsum, native sulfur). Paleosol features and carbon isotopic composition of fossil organic matter and pedogenic carbonate complement data from the mammalian fauna, the sum of which provide evidence of closed woodland to forest vegetation. Sedimentological data indicate that these wooded terrestrial habitats occurred near aquatic settings characterized by stagnant shallow waters of a freshwater lake, providing a reconstruction of unique habitats in contrast with hominin localities >4 Ma.
Collapse
Affiliation(s)
- Jonathan G Wynn
- Division of Earth Sciences, National Science Foundation, 2415 Eisenhower Ave, Alexandria, VA, 22314, USA.
| | - Laurence Dumouchel
- Center for the Advanced Study of Human Paleobiology, Science and Engineering Hall, 800 22nd St. NW, Ste 6000, Washington, DC, 20052, USA
| | - Michelle S M Drapeau
- Département d'anthropologie, Université de Montréal, C.P. 6128, Succ. Centre-ville, Montréal, QC, H3C 3J7, Canada
| |
Collapse
|
5
|
Villaseñor A, Uno KT, Kinyanjui RN, Behrensmeyer AK, Bobe R, Advokaat EL, Bamford M, Carvalho SC, Hammond AS, Palcu DV, Sier MJ, Ward CV, Braun DR. Pliocene hominins from East Turkana were associated with mesic environments in a semiarid basin. J Hum Evol 2023; 180:103385. [PMID: 37229946 DOI: 10.1016/j.jhevol.2023.103385] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 04/15/2023] [Accepted: 04/19/2023] [Indexed: 05/27/2023]
Abstract
During the middle Pliocene (∼3.8-3.2 Ma), both Australopithecus afarensis and Kenyanthropus platyops are known from the Turkana Basin, but between 3.60 and 3.44 Ma, most hominin fossils are found on the west side of Lake Turkana. Here, we describe a new hominin locality (ET03-166/168, Area 129) from the east side of the lake, in the Lokochot Member of the Koobi Fora Formation (3.60-3.44 Ma). To reconstruct the paleoecology of the locality and its surroundings, we combine information from sedimentology, the relative abundance of associated mammalian fauna, phytoliths, and stable isotopes from plant wax biomarkers, pedogenic carbonates, and fossil tooth enamel. The combined evidence provides a detailed view of the local paleoenvironment occupied by these Pliocene hominins, where a biodiverse community of primates, including hominins, and other mammals inhabited humid, grassy woodlands in a fluvial floodplain setting. Between <3.596 and 3.44 Ma, increases in woody vegetation were, at times, associated with increases in arid-adapted grasses. This suggests that Pliocene vegetation included woody species that were resilient to periods of prolonged aridity, resembling vegetation structure in the Turkana Basin today, where arid-adapted woody plants are a significant component of the ecosystem. Pedogenic carbonates indicate more woody vegetation than other vegetation proxies, possibly due to differences in temporospatial scale and ecological biases in preservation that should be accounted for in future studies. These new hominin fossils and associated multiproxy paleoenvironmental indicators from a single locale through time suggest that early hominin species occupied a wide range of habitats, possibly including wetlands within semiarid landscapes. Local-scale paleoecological evidence from East Turkana supports regional evidence that middle Pliocene eastern Africa may have experienced large-scale, climate-driven periods of aridity. This information extends our understanding of hominin environments beyond the limits of simple wooded, grassy, or mosaic environmental descriptions.
Collapse
Affiliation(s)
- Amelia Villaseñor
- Department of Anthropology, The University of Arkansas, 330 Old Main, Fayetteville, AR, 72701, USA.
| | - Kevin T Uno
- Lamont-Doherty Earth Observatory of Columbia University, Division of Biology and Paleo Environment, Palisades, NY, 10964, USA
| | - Rahab N Kinyanjui
- Department of Earth Sciences, National Museums of Kenya, Nairobi, 40658-00100, Kenya; Department of Archaeology, Max Planck Institute of Geoanthropology, 07745, Jena, Germany; Human Origins Program, National Museum of Natural History, Smithsonian Institution, MRC 121, Washington, DC, 20013, USA
| | - Anna K Behrensmeyer
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, MRC 121, Washington, DC, 20013, USA
| | - René Bobe
- Primate Models for Behavioural Evolution Lab, Institute of Human Sciences, University of Oxford, 64 Banbury Road, Oxford, OX2 6PN, UK; Gorongosa National Park, Sofala, Mozambique
| | - Eldert L Advokaat
- Department of Earth Sciences, Utrecht University, Princetonlaan 8A, 3584 CB Utrecht, the Netherlands
| | - Marion Bamford
- Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, P Bag 3, WITS, 2050, South Africa
| | - Susana C Carvalho
- Primate Models for Behavioural Evolution Lab, Institute of Human Sciences, University of Oxford, 64 Banbury Road, Oxford, OX2 6PN, UK; Gorongosa National Park, Sofala, Mozambique; Interdisciplinary Center for Archaeology and Evolution of Human Behaviour (ICArEHB), Universidade do Algarve, 8005-139, Faro, Portugal
| | - Ashley S Hammond
- Division of Anthropology, American Museum of Natural History (AMNH), New York, NY, 10024, USA; New York Consortium in Evolutionary Primatology at AMNH, New York, NY, 10024, USA
| | - Dan V Palcu
- Oceanographic Institute of the University of São Paulo, Brazil; Paleomagnetic Laboratory 'Fort Hoofddijk', Utrecht University, Budapestlaan 17, 3584 CD, Utrecht, the Netherlands
| | - Mark J Sier
- Centro Nacional de Investigación Sobre la Evolución Humana (CENIEH), Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain; Department of Earth Sciences, University of Oxford, South Parks Road, OX1 3AN, Oxford, UK; Department of Earth Sciences, Utrecht University, Princetonlaan 8A, 3584 CB Utrecht, the Netherlands
| | - Carol V Ward
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - David R Braun
- Center for the Advanced Study of Human Paleobiology, Anthropology Department, George Washington University, Washington, DC, USA
| |
Collapse
|
6
|
Ramírez-Pedraza I, Martínez LM, Aouraghe H, Rivals F, Tornero C, Haddoumi H, Estebaranz-Sánchez F, Rodríguez-Hidalgo A, van der Made J, Oujaa A, Ibáñez JJ, Mhamdi H, Souhir M, Aissa AM, Chacón MG, Sala-Ramos R. Multiproxy approach to reconstruct fossil primate feeding behavior: Case study for macaque from the Plio-Pleistocene site Guefaït-4.2 (eastern Morocco). Front Ecol Evol 2023. [DOI: 10.3389/fevo.2023.1011208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
The genus Macaca belongs to Cercopithecidae (Old World monkeys), Cercopithecinae, Papionini. The presence of Macaca in North Africa is well known from the Late Miocene to the Late Pleistocene. However, the diet of fossil Macaca has been poorly described in the literature. In this study, we investigated the feeding habits of Macaca cf. sylvanus (n = 4) from the Plio-Pleistocene site Guefaït-4.2 in eastern Morocco through multiproxy analysis combining analyses of stable carbon and oxygen isotopes from tooth enamel, buccal microtexture, and low-magnification occlusal dental microwear. For both microwear analyses, we compared the macaques with a new reference collection of extant members of Cercopithecoidea. Our occlusal microwear results show for the fossil macaque a pattern similar to the extant Cercocebus atys and Lophocebus albigena, African forest-dwelling species that are characterized by a durophagous diet based mainly on hard fruit and seed intake. Buccal microtexture results also suggest the consumption of some grasses and the exploitation of more open habitats, similar to that observed in Theropithecus gelada. The δ13C of M. cf. sylvanus indicates a C3 based-diet without the presence of C4 plants typical of the savanna grassland in eastern Africa during this period. The high δ18O values of M. cf. sylvanus, compared with the contemporary ungulates recovered from Guefaït-4.2, could be associated with the consumption of a different resource by the primate such as leaves or fresh fruits from the upper part of trees. The complementarity of these methods allows for a dietary reconstruction covering a large part of the individual’s life.
Collapse
|
7
|
A nonanalog Pliocene ungulate community at Laetoli with implications for the paleoecology of Australopithecus afarensis. J Hum Evol 2022; 167:103182. [DOI: 10.1016/j.jhevol.2022.103182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 11/17/2022]
|
8
|
Dumouchel L, Bobe R, Wynn JG, Barr WA. The environments of Australopithecus anamensis at Allia Bay, Kenya: A multiproxy analysis of early Pliocene Bovidae. J Hum Evol 2021; 151:102928. [PMID: 33453510 DOI: 10.1016/j.jhevol.2020.102928] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 12/01/2020] [Accepted: 12/01/2020] [Indexed: 11/18/2022]
Abstract
Australopithecus anamensis, among the earliest fully bipedal hominin species, lived in eastern Africa around 4 Ma. Much of what is currently known about the paleoecology of A. anamensis comes from the type locality, Kanapoi, Kenya. Here, we extend knowledge of the range of environments occupied by A. anamensis by presenting the first multiproxy paleoecological analysis focusing on Bovidae excavated from another important locality where A. anamensis was recovered, locality 261-1 (ca. 3.97 Ma) at Allia Bay, East Turkana, Kenya. Paleoenvironments are reconstructed using astragalar ecomorphology, mesowear, hypsodonty index, and oxygen and carbon isotopes from dental enamel. We compare our results to those obtained from Kanapoi. Our results show that the bovid community composition is similar between the two fossil assemblages. Allia Bay and Kanapoi bovid astragalar ecomorphology spans the spectrum of modern morphologies indicative of grassland, woodland, and even forest-adapted forms. Dietary reconstructions based on stable isotopes, mesowear, and hypsodonty reveal that these bovids' diet encompassed the full C3 to C4 dietary spectrum and overlap in the two data sets. Our results allow us to confidently extend our reconstructions of the paleoenvironments of A. anamensis at Kanapoi to Allia Bay, where this pivotal hominin species is associated with heterogeneous settings including habitats with varying degrees of tree cover, including grasslands, bushlands, and woodlands.
Collapse
Affiliation(s)
- Laurence Dumouchel
- Department of Anthropology, Wichita State University, 1845 Fairmount Street, Wichita, KS 67260, USA.
| | - René Bobe
- Primate Models for Behavioural Evolution Lab, Institute of Cognitive & Evolutionary Anthropology, School of Anthropology, University of Oxford, 64 Banbury Rd, Park Town, Oxford, OX2 6PN, UK; Paleo-Primate Project Gorongosa, Gorongosa National Park, Sofala, Mozambique; Interdisciplinary Center for Archaeology and Evolution of Human Behaviour (ICArEHB), Universidade Do Algarve, Campus de Penha, Faro, 8005-139, Portugal
| | - Jonathan G Wynn
- Division of Earth Sciences, National Science Foundation, 2415 Eisenhower Avenue, Alexandria, VA 22314, USA
| | - W Andrew Barr
- Center for the Advanced Study of Human Paleobiology, The George Washington University, 800 22(nd)Street Northwest, Suite 6000, Washington, DC 20052, USA
| |
Collapse
|
9
|
Faith JT, Rowan J, Du A, Koch PL. Plio-Pleistocene decline of African megaherbivores: No evidence for ancient hominin impacts. Science 2019; 362:938-941. [PMID: 30467167 DOI: 10.1126/science.aau2728] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/28/2018] [Indexed: 12/24/2022]
Abstract
It has long been proposed that pre-modern hominin impacts drove extinctions and shaped the evolutionary history of Africa's exceptionally diverse large mammal communities, but this hypothesis has yet to be rigorously tested. We analyzed eastern African herbivore communities spanning the past 7 million years-encompassing the entirety of hominin evolutionary history-to test the hypothesis that top-down impacts of tool-bearing, meat-eating hominins contributed to the demise of megaherbivores prior to the emergence of Homo sapiens We document a steady, long-term decline of megaherbivores beginning ~4.6 million years ago, long before the appearance of hominin species capable of exerting top-down control of large mammal communities and predating evidence for hominin interactions with megaherbivore prey. Expansion of C4 grasslands can account for the loss of megaherbivore diversity.
Collapse
Affiliation(s)
- J Tyler Faith
- Natural History Museum of Utah, University of Utah, Salt Lake City, UT 84108, USA. .,Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA
| | - John Rowan
- Institute of Human Origins and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85282, USA.,Department of Anthropology, University of Massachusetts, Amherst, MA 01003, USA
| | - Andrew Du
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
| | - Paul L Koch
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA
| |
Collapse
|