Quantitative genetics of body size evolution on islands: an individual-based simulation approach

According to the island rule, small-bodied vertebrates will tend to evolve larger body size on islands, whereas the opposite happens to large-bodied species. This controversial pattern has been studied at the macroecological and biogeographical scales, but new developments in quantitative evolutionary genetics now allow studying the island rule from a mechanistic perspective. Here, we develop a simulation approach based on an individual-based model to model body size change on islands as a progressive adaptation to a moving optimum, determined by density-dependent population dynamics. We applied the model to evaluate body size differentiation in the pigmy extinct hominin Homo floresiensis, showing that dwarfing may have occurred in only about 360 generations (95% CI ranging from 150 to 675 generations). This result agrees with reports suggesting rapid dwarfing of large mammals on islands, as well as with the recent discovery that small-sized hominins lived in Flores as early as 700 kyr ago. Our simulations illustrate the power of analysing ecological and evolutionary patterns from an explicit quantitative genetics perspective.

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Diversification rates and phenotypic evolution in venomous snakes (Elapidae)

Royal Society Open Science ◽

10.1098/rsos.150277 ◽

2016 ◽

Vol 3 (1) ◽

pp. 150277 ◽

Cited By ~ 51

Author(s):

Michael S. Y. Lee ◽

Kate L. Sanders ◽

Benedict King ◽

Alessandro Palci

Keyword(s):

Body Size ◽

Phylogenetic Trees ◽

Phenotypic Evolution ◽

Passerine Birds ◽

Size Change ◽

Background Rate ◽

Venomous Snakes ◽

Size Evolution ◽

Speciation Rates ◽

The Relationship

The relationship between rates of diversification and of body size change (a common proxy for phenotypic evolution) was investigated across Elapidae, the largest radiation of highly venomous snakes. Time-calibrated phylogenetic trees for 175 species of elapids (more than 50% of known taxa) were constructed using seven mitochondrial and nuclear genes. Analyses using these trees revealed no evidence for a link between speciation rates and changes in body size. Two clades ( Hydrophis , Micrurus ) show anomalously high rates of diversification within Elapidae, yet exhibit rates of body size evolution almost identical to the general elapid ‘background’ rate. Although correlations between speciation rates and rates of body size change exist in certain groups (e.g. ray-finned fishes, passerine birds), the two processes appear to be uncoupled in elapid snakes. There is also no detectable shift in diversification dynamics associated with the colonization of Australasia, which is surprising given that elapids appear to be the first clade of venomous snakes to reach the continent.

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Reconstructed evolutionary patterns for crocodile-line archosaurs demonstrate impact of failure to log-transform body size data

10.31233/osf.io/k3dwf ◽

2021 ◽

Author(s):

Roger Benson ◽

Pedro L Godoy ◽

Mario Bronzati ◽

Richard Butler ◽

William Gearty

Keyword(s):

Body Size ◽

Measurement Data ◽

Methodological Error ◽

Evolutionary Patterns ◽

Aquatic Life ◽

Rates Of Evolution ◽

Size Evolution ◽

Main Driver ◽

Body Size Evolution ◽

Phylogenetic Lineages

Pseudosuchia includes crocodylians, plus all extinct species more closely related to them than to birds. They appeared around 250 million years ago and have a rich fossil history, showing extinct diversity that exceeds that of their living members1-4. Recently, Stockdale & Benton5 presented analyses of a new dataset of body size estimates spanning the entire evolutionary history of this group. They quantified patterns of average body size, body size disparity through time, and rates of evolution along phylogenetic lineages. Their results suggest that pseudosuchians exhibited considerable variation in rates of body size evolution, for which they provided various group-specific explanations and asserted the importance of climatic drivers. This differs from two recent studies that analysed a substantial portion of pseudosuchian body size evolution and proposed that adaptation to aquatic life, a biological innovation of some subgroups, was the main driver of body size evolution, with patterns of disparity also being influenced by size-dependent extinction risk6,7. Here we show that the analytical results of Stockdale & Benton5 are strongly influenced by a methodological error in their body size index. Specifically, that they chose not to log-transform measurement data prior to analyses.

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Island Rule, quantitative genetics and brain–body size evolution in Homo floresiensis

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.1065 ◽

2017 ◽

Vol 284 (1857) ◽

pp. 20171065 ◽

Cited By ~ 14

Author(s):

José Alexandre Felizola Diniz-Filho ◽

Pasquale Raia

Keyword(s):

Body Size ◽

Brain Size ◽

Natural Populations ◽

Direct Analysis ◽

Neutral Evolution ◽

Island Rule ◽

Selection Gradients ◽

Size Evolution ◽

Evolutionary Trajectories ◽

Selective Forces

Colonization of islands often activate a complex chain of adaptive events that, over a relatively short evolutionary time, may drive strong shifts in body size, a pattern known as the Island Rule. It is arguably difficult to perform a direct analysis of the natural selection forces behind such a change in body size. Here, we used quantitative evolutionary genetic models, coupled with simulations and pattern-oriented modelling, to analyse the evolution of brain and body size in Homo floresiensis , a diminutive hominin species that appeared around 700 kya and survived up to relatively recent times (60–90 kya) on Flores Island, Indonesia. The hypothesis of neutral evolution was rejected in 97% of the simulations, and estimated selection gradients are within the range found in living natural populations. We showed that insularity may have triggered slightly different evolutionary trajectories for body and brain size, which means explaining the exceedingly small cranial volume of H. floresiensis requires additional selective forces acting on brain size alone. Our analyses also support previous conclusions that H. floresiensis may be most likely derived from an early Indonesian H. erectus , which is coherent with currently accepted biogeographical scenario for Homo expansion out of Africa.

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The island rule explains consistent patterns of body size evolution across terrestrial vertebrates

10.1101/2020.05.25.114835 ◽

2020 ◽

Author(s):

Ana Benítez-López ◽

Luca Santini ◽

Juan Gallego-Zamorano ◽

Borja Milá ◽

Patrick Walkden ◽

...

Keyword(s):

Body Size ◽

Meta Analysis ◽

Island Rule ◽

Island Size ◽

Terrestrial Vertebrates ◽

Size Evolution ◽

Evolutionary Trajectories ◽

Body Size Evolution ◽

Large Animals ◽

General Explanation

AbstractIsland faunas can be characterized by gigantism in small animals and dwarfism in large animals, but the extent to which this so-called ‘island rule’ provides a general explanation for evolutionary trajectories on islands remains contentious. Here we use a phylogenetic meta-analysis to assess patterns and drivers of body size evolution across a global sample of paired island-mainland populations of terrestrial vertebrates. We show that ‘island rule’ effects are widespread in mammals, birds and reptiles, but less evident in amphibians, which mostly tend towards gigantism. We also found that the magnitude of insular dwarfism and gigantism is mediated by climate as well as island size and isolation, with more pronounced effects in smaller, more remote islands for mammals and reptiles. We conclude that the island rule is pervasive across vertebrates, but that the implications for body size evolution are nuanced and depend on an array of context-dependent ecological pressures and environmental conditions.

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INTEGRATING MACROECOLOGY AND QUANTITATIVE GENETICS: EVOLUTION OF BODY SIZE AND BRAIN SIZE UNDER ISLAND RULE

Oecologia Australis ◽

10.4257/oeco.2018.2202.09 ◽

2018 ◽

Vol 22 (02) ◽

pp. 201-209

Author(s):

José Alexandre Felizola Diniz-Filho ◽

Wanderson Santos ◽

Lucas Jardim

Keyword(s):

Body Size ◽

Quantitative Genetics ◽

Brain Size ◽

Island Rule

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Resurrection of the island rule – human-driven extinctions have obscured a basic evolutionary pattern

10.1101/025486 ◽

2015 ◽

Cited By ~ 2

Author(s):

Søren Faurby ◽

Jens-Christian Svenning

Keyword(s):

Late Quaternary ◽

Strong Support ◽

The Body ◽

Island Rule ◽

Evolutionary Patterns ◽

Data Set ◽

Evolutionary Pattern ◽

Size Evolution ◽

Body Sizes ◽

The Many

Islands are or have been occupied by unusual species, such as dwarf proboscideans and giant rodents. The discussion of the classical but controversial “island rule,” which states that mammalian body sizes converge on intermediate sizes on islands, has been stimulated by these unusual species. In this paper, we use an unprecedented global data set of the distributions and the body sizes of mammals and a novel analytical method to analyze body size evolution on islands; the analyses produced strong support for the island rule. Islands have suffered massive human-driven losses of species, and we found that the support for the island rule was substantially stronger when the many late-Quaternary extinct species were also considered (particularly, the tendency for dwarfing in large taxa). In this study, the decisive support generated for the island rule confirmed that evolution is markedly different on islands and that human impact may obscure even fundamental evolutionary patterns.

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Body size evolution in insular vertebrates: generality of the island rule

Journal of Biogeography ◽

10.1111/j.1365-2699.2005.01314.x ◽

2005 ◽

Vol 32 (10) ◽

pp. 1683-1699 ◽

Cited By ~ 341

Author(s):

Mark V. Lomolino

Keyword(s):

Body Size ◽

Island Rule ◽

Size Evolution ◽

Body Size Evolution

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An Italian dinosaur Lagerstätte reveals the tempo and mode of hadrosauriform body size evolution

Scientific Reports ◽

10.1038/s41598-021-02490-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alfio Alessandro Chiarenza ◽

Matteo Fabbri ◽

Lorenzo Consorti ◽

Marco Muscioni ◽

David C. Evans ◽

...

Keyword(s):

Body Size ◽

Mediterranean Region ◽

Type Specimen ◽

Skeletal Remains ◽

The Body ◽

Evolutionary Trend ◽

Island Rule ◽

Size Evolution ◽

North Eastern ◽

Body Size Evolution

AbstractDuring the latest Cretaceous, the European Archipelago was characterized by highly fragmented landmasses hosting putative dwarfed, insular dinosaurs, claimed as fossil evidence of the “island rule”. The Villaggio del Pescatore quarry (north-eastern Italy) stands as the most informative locality within the palaeo-Mediterranean region and represents the first, multi-individual Konservat-Lagerstätte type dinosaur-bearing locality in Italy. The site is here critically re-evaluated as early Campanian in age, thus preceding the final fragmentation stages of the European Archipelago, including all other European localities preserving hypothesized dwarfed taxa. New skeletal remains allowed osteohistological analyses on the hadrosauroid Tethyshadros insularis indicating subadult features in the type specimen whereas a second, herein newly described, larger individual is likely somatically mature. A phylogenetic comparative framework places the body-size of T. insularis in range with other non-hadrosaurid Eurasian hadrosauroids, rejecting any significant evolutionary trend towards miniaturisation in this clade, confuting its ‘pygmy’ status, and providing unmatched data to infer environmentally-driven body-size trends in Mesozoic dinosaurs.

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