Hominin taxic diversity: Fact or fantasy?

Wood, Bernard; Boyle, Eve K.

doi:10.1002/ajpa.22902

Cited by 151 publications

(100 citation statements)

References 316 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our assessment used a framework phylogeny based on widely agreed evolutionary relationships and on the currently estimated first and last appearance dates for eight of the most broadly accepted hominin species ( Fig. 1 and Table S1) (11). Amounts of change along each branch of the hominin phylogenetic tree estimated through this variable-rate approach were compared with the amount of change observed in evolutionary simulations that used a constant-variance Brownian motion (BM) model (12) in which traits evolve neutrally and at a constant rate without directional trends in any particular branch of the hominin phylogeny (Materials and Methods).…”

mentioning

confidence: 99%

Brain enlargement and dental reduction were not linked in hominin evolution

Gómez‐Robles

Smaers

Holloway

et al. 2017

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

View full text Add to dashboard Cite

The large brain and small postcanine teeth of modern humans are among our most distinctive features, and trends in their evolution are well studied within the hominin clade. Classic accounts hypothesize that larger brains and smaller teeth coevolved because behavioral changes associated with increased brain size allowed a subsequent dental reduction. However, recent studies have found mismatches between trends in brain enlargement and posterior tooth size reduction in some hominin species. We use a multiple-variance Brownian motion approach in association with evolutionary simulations to measure the tempo and mode of the evolution of endocranial and dental size and shape within the hominin clade. We show that hominin postcanine teeth have evolved at a relatively consistent neutral rate, whereas brain size evolved at comparatively more heterogeneous rates that cannot be explained by a neutral model, with rapid pulses in the branches leading to later Homo species. Brain reorganization shows evidence of elevated rates only much later in hominin evolution, suggesting that fast-evolving traits such as the acquisition of a globular shape may be the result of direct or indirect selection for functional or structural traits typical of modern humans.endocast | postcanine teeth | evolutionary rates | selection | paleoanthropology I n comparison with other hominins, modern humans are characterized by their large brain and small posterior teeth. These traits are among our most distinctive features, and trends in their evolution are well studied because of the phylogenetic and functional implications of variation in dental and cerebral anatomy (1-3). Brain expansion and postcanine reduction appear to follow parallel trends during hominin evolution, and classic views consider that an increase in brain size was linked to more complex behavior that included the manufacture and use of stone tools, which allowed a subsequent dental reduction. A shift toward a higher-quality diet during the evolution of early Homo also has been related to brain size increase and posterior tooth reduction (4, 5). However, it has been suggested recently that brain expansion in early Homo, as inferred from endocranial volume, substantially preceded dental reduction (6). It also has been noted that early in the Neanderthal lineage strong dental reduction preceded the additional brain expansion seen in the later "classic" Neanderthals (7). The suggestion that stone tool use and manufacture substantially predated the increase in brain size observed in early Homo (8) adds further complexity to this scenario.Recent developments in ancestral state reconstruction (9, 10) allow lineage-specific patterns of brain expansion and dental reduction to be quantified and compared. Unlike traditional approaches to ancestral state reconstruction that assume a neutral evolutionary scenario, which is likely unrealistic in most cases, we used a variable rate approach that estimates differences in evolutionary rates across different branches of a given phylogeny. We appli...

show abstract

mentioning

confidence: 99%

Brain enlargement and dental reduction were not linked in hominin evolution

Gómez‐Robles

Smaers

Holloway

et al. 2017

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

View full text Add to dashboard Cite

show abstract

“…Phylogenetic tree showing how introgression caused the speciation of humans. This introgression speciation model predicts an early split for Paranthropus and Australopithecus , increasingly shown in the fossil record (Haile-Selassie, 2015Wood, 2016), and also shows that the evolution of genes that ended up in Australopithecus , and therefore in extant humans, as well as in Paranthropus , can and should be traced along the gorilla lineage as well.…”

mentioning

confidence: 62%

“…deyiremeda is better classified as a Paranthropus , P. deyiremeda , and that an early split between Paranthropus and Australopithecus is the reason there were two separate lineages of hominins during the Pliocene (Haile-Selassie, 2015Wood, 2016) , clearly distinguishable by their locomotor adaptation and diet . ( Haile-Selassie, 2015), contemporaneous with Au.…”

Section: Gorilla Gorillamentioning

confidence: 99%

See 1 more Smart Citation

The speciation of Australopithecus and Paranthropus was caused by introgression from the Gorilla lineage

Nygren¹

2018

Preprint

View full text Add to dashboard Cite

The discovery of Paranthropus deyiremeda in 3.3-3.5 million year old fossil sites in Afar (Haile-Selassie, 2015), together with 30% of the gorilla genome showing lineage sorting between humans and chimpanzees (Scally, 2012), and a NUMT ("nuclear mitochondrial DNA segment") that is shared by both gorillas, humans and chimpanzees, and that dates back to 6 million years ago (Popadin, 2017), is conclusive evidence that introgression from the gorilla lineage caused the speciation of both the Australopithecus lineage and the Paranthropus lineage, providing a lens into the gorilla-like features within Paranthropus , as well as traits within Homo that originate from the gorilla branch, such as a high opposable thumb index (Almécija, 2015), an adducted great toe (Tocheri, 2011;McHenry, 2006), and large deposits of subcutaneous fat. (Haile-Selassie, 2015Wood, 2016), and also shows that the evolution of genes that ended up in Australopithecus , and therefore in extant humans, as well as in Paranthropus , can and should be traced along the gorilla lineage as well.

show abstract

“…The implications of the above are that hominins are not as well known as might be expected based on the number of published articles on this group, and that a substantial amount of the hominin fossil record may be unknown. This claim is bolstered by the relatively large number of new hominin taxa named over the past 25 years, which has nearly doubled the number of putative hominin species (see citations in Wood and Boyle 56 ). As such, it is likely that even the more generous estimates for hominin species durations significantly underestimate the true temporal ranges of these taxa, and this needs to be considered when evaluating hypotheses of ancestor-descendant relationships.…”

Section: The Incomplete Nature Of the Fossil Recordmentioning

confidence: 99%

Temporal ranges and ancestry in the hominin fossil record: The case of Australopithecus sediba

Robinson¹,

Campbell²,

Cote³

et al. 2018

S. Afr. J. Sci.

View full text Add to dashboard Cite

In attempting to resolve the phylogenetic relationships of fossil taxa, researchers can use evidence from two sources -morphology and known temporal ranges. For most taxa, the available evidence is stronger for one of these data sources. We examined the limitations of temporal data for reconstructing hominin evolutionary relationships, specifically focusing on the hypothesised ancestor-descendant relationship between Australopithecus sediba and the genus Homo. Some have implied that because the only known specimens of A. sediba are dated to later than the earliest fossils attributed to Homo, the former species is precluded from being ancestral to the latter. However, A. sediba is currently known from one site dated to 1.98 Ma and, thus, its actual temporal range is unknown. Using data from the currently known temporal ranges of fossil hominin species, and incorporating dating error in the analysis, we estimate that the average hominin species' temporal range is ~0.97 Myr, which is lower than most figures suggested for mammalian species generally. Using this conservative figure in a thought experiment in which the Malapa specimens are hypothesised to represent the last appearance date, the middle of the temporal range, and first appearance date for the species, the first appearance date of A. sediba would be 2.95, 2.47 and 1.98 Ma, respectively. As these scenarios are all equally plausible, and 2.95 Ma predates the earliest specimens that some have attributed to Homo, we cannot refute the hypothesis that the species A. sediba is ancestral to our genus based solely on currently available temporal data. Significance:• We correct a common misconception in palaeoanthropology that a species currently known only from later in time than another species cannot be ancestral to it.• On temporal grounds alone one cannot dismiss the possibility that A. sediba could be ancestral to the genus Homo.

show abstract

Hominin taxic diversity: Fact or fantasy?

Cited by 151 publications

References 316 publications

Brain enlargement and dental reduction were not linked in hominin evolution

Brain enlargement and dental reduction were not linked in hominin evolution

The speciation of Australopithecus and Paranthropus was caused by introgression from the Gorilla lineage

Temporal ranges and ancestry in the hominin fossil record: The case of Australopithecus sediba

Contact Info

Product

Resources

About