Testing gradual and speciational models of evolution in extant taxa: the example of ratites

  title={Testing gradual and speciational models of evolution in extant taxa: the example of ratites},
  author={Michel Laurin and Sander W. S. Gussekloo and David Marjanovi{\'c} and Laurent Legendre and Jorge Cubo},
  journal={Journal of Evolutionary Biology},
Abstract  Ever since Eldredge and Gould proposed their model of punctuated equilibria, evolutionary biologists have debated how often this model is the best description of nature and how important it is compared to the more gradual models of evolution expected from natural selection and the neo‐Darwinian paradigm. Recently, Cubo proposed a method to test whether morphological data in extant ratites are more compatible with a gradual or with a speciational model (close to the punctuated… 

Ratite nonmonophyly: independent evidence from 40 novel Loci.

The results strongly support the recent molecular studies, revealing that the deepest branch within Palaeognathae separates the ostrich from other members of the clade, rather than the traditional hypothesis that separates the tinamous from the ratites.

Experimental systematics: sensitivity of cladistic methods to polarization and character ordering schemes

The results of simulations of the evolution of phenotypic traits under a Brownian motion model are presented to characterize differences in sensitivity between parsimony and 3ta to outgroup branch length, which affects the reliability of ancestral character state estimates, (2) character state ordering scheme, and (3) ingroup branch lengths that reflect the geological age of studied taxa.

Evolutionary mode routinely varies among morphological traits within fossil species lineages

Recent studies have revitalized interest in methods for detecting evolutionary modes in both fossil sequences and phylogenies. Most of these studies examine single size or shape traits, often

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Characters of the South American avian fossil record are presence of taxa with uncertain affinities and the absence of Passeriformes during the Paleogene; progressive and accelerated increase of species starting at the Neogene (Miocene); and predominance of the zoophagous birds in all the associations under scrutiny.

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South American and Antarctic Continental Cenozoic Birds: Paleobiogeographic Affinities and Disparities

Several advances have been made on the understanding of the biotic and environmental history of South America and Antarctica including the discovery of additional fossil sites coupled with progress



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This method is applied to a dataset from ratites and concludes that, for a range of morphological features, change tends to have been speciational rather than gradual.

Punctuated equilibria: the tempo and mode of evolution reconsidered

It is argued that virtually none of the examples brought forward to refute the model of punctuated equilibria can stand as support for phyletic gradualism; many are so weak and ambiguous that they only reflect the persistent bias for gradualism still deeply embedded in paleontological thought.

Using Phylogenies to Test Macroevolutionary Hypotheses of Trait Evolution in Cranes (Gruinae)

A novel phylogenetic approach to the study of trait evolution is presented, employing a method that avoids point estimates of ancestor reconstructions and considers a new nonhistorical model in which changes are completely independent of history, such that differences among species are expected to be the same, regardless of relationship.

Phylogenomic evidence for multiple losses of flight in ratite birds

A phylogenetic analyses of 20 unlinked nuclear genes reveal a genome-wide signal that unequivocally places tinamous within ratites, making ratites polyphyletic and suggesting multiple losses of flight.

The evolution of body size, Cope's rule and the origin of amniotes.

  • M. Laurin
  • Biology, Environmental Science
    Systematic biology
  • 2004
Character optimization, permutational multiple linear regressions, and independent contrast analyses show that Cope's rule of phyletic size increase applies to early reptiliomorphs but that it does not apply to early stegocephalians globally.


It was found that correlations estimated without taking phylogeny into account were often quite poor and never substantially better than those produced by the other tested methods, while Felsenstein's independent contrasts (FIC) method gave the best performance in many cases, even when weak constraints had been acting throughout phenotypic evolution.

The evolutionary radiation of modern birds (Neornithes): reconciling molecules, morphology and the fossil record

Current understanding of the early fossil history of Neornithes is highlighted in conjunction with available phylogenetic resolution for the major extant clades, as well as recent advancements in genetic methods that have constrained time estimates for major evolutionary divergences.

New morphological evidence supports congruent phylogenies and Gondwana vicariance for palaeognathous birds

A morphological phylogeny based mainly on new characters from the tongue apparatus and cranial osteology, with a theoretical ancestor as outgroup is reported, fully consistent with a Gondwana vicariance model of evolution.


The results suggest that the great majority of estimated phylogenetic trees are likely to be quite inaccurate; they underscore the inappropriateness of characterizing current phylogenetic methods as being for reconstruction rather than for estimation.

Speciation in the fossil record.