Estimating origination times from the early hominin fossil record

Sporadic sampling, not climatic forcing, drives observed early hominin diversity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1721538115 ◽

2018 ◽

Vol 115 (19) ◽

pp. 4891-4896 ◽

Cited By ~ 4

Author(s):

Simon J. Maxwell ◽

Philip J. Hopley ◽

Paul Upchurch ◽

Christophe Soligo

Keyword(s):

Fossil Record ◽

Detailed Examination ◽

Hominin Evolution ◽

Rock Exposure ◽

Early Hominin ◽

Positive Correlations ◽

Taxic Diversity ◽

Diversity Estimates

The role of climate change in the origin and diversification of early hominins is hotly debated. Most accounts of early hominin evolution link observed fluctuations in species diversity to directional shifts in climate or periods of intense climatic instability. None of these hypotheses, however, have tested whether observed diversity patterns are distorted by variation in the quality of the hominin fossil record. Here, we present a detailed examination of early hominin diversity dynamics, including both taxic and phylogenetically corrected diversity estimates. Unlike past studies, we compare these estimates to sampling metrics for rock availability (hominin-, primate-, and mammal-bearing formations) and collection effort, to assess the geological and anthropogenic controls on the sampling of the early hominin fossil record. Taxic diversity, primate-bearing formations, and collection effort show strong positive correlations, demonstrating that observed patterns of early hominin taxic diversity can be explained by temporal heterogeneity in fossil sampling rather than genuine evolutionary processes. Peak taxic diversity at 1.9 million years ago (Ma) is a sampling artifact, reflecting merely maximal rock availability and collection effort. In contrast, phylogenetic diversity estimates imply peak diversity at 2.4 Ma and show little relation to sampling metrics. We find that apparent relationships between early hominin diversity and indicators of climatic instability are, in fact, driven largely by variation in suitable rock exposure and collection effort. Our results suggest that significant improvements in the quality of the fossil record are required before the role of climate in hominin evolution can be reliably determined.

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‘Do larger molars and robust jaws in early hominins represent dietary adaptation?’ A New Study in Tooth Wear

Archaeology International ◽

10.5334/ai.1605 ◽

2013 ◽

Vol No. 16 (2012-2013) ◽

Cited By ~ 2

Author(s):

Anna Clement ◽

Simon Hillson

Keyword(s):

Stable Isotopes ◽

Fossil Record ◽

Tooth Wear ◽

Dental Microwear ◽

Alternative Source ◽

Dietary Adaptation ◽

Early Hominin ◽

First Time ◽

Source Of Information ◽

Lines Of Evidence

Diet imposes significant constraints on the biology and behaviour of animals. The fossil record suggests that key changes in diet have taken place throughout the course of human evolution. Defining these changes enables us to understand the behaviour of our extinct fossil ancestors. Several lines of evidence are available for studying the diet of early hominins, including craniodental morphology, palaeoecology, dental microwear and stable isotopes. They do, however, often provide conflicting results. Using dental macrowear analysis, this new UCL Institute of Archaeology project will provide an alternative source of information on early hominin diet. Dental macrowear has often been used to analyse diet in archaeological populations, but this will be the first time that this type of detailed study has been applied to the early hominin fossil record.

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Does the fossil record of spiders track that of their principal prey, the insects?

Transactions of the Royal Society of Edinburgh Earth Sciences ◽

10.1017/s026359330300018x ◽

2003 ◽

Vol 94 (03) ◽

pp. 275 ◽

Cited By ~ 1

Keyword(s):

Fossil Record

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Molecular clock tied to fossil record

Nature ◽

10.1038/news041011-2 ◽

2004 ◽

Author(s):

Emma Marris

Keyword(s):

Molecular Clock ◽

Fossil Record

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Darwin's two competing phylogenetic trees: marsupials as ancestors or sister taxa?

Archives of Natural History ◽

10.3366/anh.2012.0091 ◽

2012 ◽

Vol 39 (2) ◽

pp. 217-233 ◽

Cited By ~ 4

Author(s):

J. David Archibald

Keyword(s):

Fossil Record ◽

Evolutionary Biology ◽

Phylogenetic Trees ◽

Charles Darwin ◽

The Other ◽

Charles Lyell ◽

Single Origin ◽

Molecular Studies ◽

Richard Owen ◽

First Time

Studies of the origin and diversification of major groups of plants and animals are contentious topics in current evolutionary biology. This includes the study of the timing and relationships of the two major clades of extant mammals – marsupials and placentals. Molecular studies concerned with marsupial and placental origin and diversification can be at odds with the fossil record. Such studies are, however, not a recent phenomenon. Over 150 years ago Charles Darwin weighed two alternative views on the origin of marsupials and placentals. Less than a year after the publication of On the origin of species, Darwin outlined these in a letter to Charles Lyell dated 23 September 1860. The letter concluded with two competing phylogenetic diagrams. One showed marsupials as ancestral to both living marsupials and placentals, whereas the other showed a non-marsupial, non-placental as being ancestral to both living marsupials and placentals. These two diagrams are published here for the first time. These are the only such competing phylogenetic diagrams that Darwin is known to have produced. In addition to examining the question of mammalian origins in this letter and in other manuscript notes discussed here, Darwin confronted the broader issue as to whether major groups of animals had a single origin (monophyly) or were the result of “continuous creation” as advocated for some groups by Richard Owen. Charles Lyell had held similar views to those of Owen, but it is clear from correspondence with Darwin that he was beginning to accept the idea of monophyly of major groups.

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