The new framework for understanding placental mammal evolution

  title={The new framework for understanding placental mammal evolution},
  author={Robert J. Asher and Nigel Charles Bennett and Thomas Lehmann},
An unprecedented level of confidence has recently crystallized around a new hypothesis of how living placental mammals share a pattern of common descent. The major groups are afrotheres (e.g., aardvarks, elephants), xenarthrans (e.g., anteaters, sloths), laurasiatheres (e.g., horses, shrews), and euarchontoglires (e.g., humans, rodents). Compared with previous hypotheses this tree is remarkably stable; however, some uncertainty persists about the location of the placental root, and (for example… 
Nomenclature and placental mammal phylogeny
It is concluded that no matter how reconstructions of the Tree of Life change in years to come, systematists should apply new names reluctantly, deferring to those already published and maximizing consistency with existing nomenclature.
It is shown that afrotherians significantly differ from other placentals by an early ossification of the orbitosphenoid and caudal vertebrae, and the results suggest that developmental homogeneity in some ossified sequences may be restricted to northern placental mammals (Boreoeutheria).
The Chromosomes of Afrotheria and Their Bearing on Mammalian Genome Evolution
Current knowledge on Afrotheria chromosomes and genome evolution suggests that further work on this apparently bizarre assemblage of mammals will provide important data to a better understanding on mammalian genome evolution.
The Placental Mammal Ancestor and the Post–K-Pg Radiation of Placentals
A phylogenetic tree shows that crown clade Placentalia and placental orders originated after the K-Pg boundary, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats).
Ancient collagen reveals evolutionary history of the endemic South American ‘ungulates’
  • M. Buckley
  • Biology
    Proceedings of the Royal Society B: Biological Sciences
  • 2015
A molecular phylogeny for both Macrauchenia patachonica (Litopterna) and Toxodon platensis (Notoungulata) recovered using proteomics-based (liquid chromatography–tandem mass spectrometry) sequencing analyses of bone collagen is presented, placing both taxa in a clade that is monophyletic with the perissodactyls, which today are represented by horses, rhinoceroses and tapirs.
Placental Evolution within the Supraordinal Clades of Eutheria with the Perspective of Alternative Animal Models for Human Placentation
Current evolutionary studies have contributed essentially to providing a pool of experimental models for recent and future approaches that may also meet the requirements of a long gestation period and advanced developmental status of the newborn in the human.
Resolving conflict in eutherian mammal phylogeny using phylogenomics and the multispecies coalescent model
It is demonstrated that the incongruence introduced by concatenation methods is a major cause of long-standing uncertainty in the phylogeny of eutherian mammals, and the same may apply to other clades and the analyses suggest that such incONGruence can be resolved using phylogenomic data and coalescent methods that deal explicitly with gene tree heterogeneity.
Advantages and Limitations in the Use of Extant Xenarthrans (Mammalia) as Morphological Models for Paleobiological Reconstruction
The limitations of the use of extant xenarthrans as morphological models for paleobiological reconstructions are evaluated and the need to apply other approaches, such as mechanics, that address form-function relationships but are not necessarily based on known biological comparators is suggested.
New Early Diverging Cingulate (Xenarthra: Peltephilidae) from the Late Oligocene of Bolivia and Considerations Regarding the Origin of Crown Xenarthra
Turtles of the clade Pan-Testudinoidea have a rich fossil record in North America, including the Caribbean, ranging from the late Paleocene to the Holocene, and an updated global phylogeny allows attribution of fossils to these lineages with confidence that allows the discernment of new diversity trends and biogeographic patterns.
The Placentation of Eulipotyphla—Reconstructing a Morphotype of the Mammalian Placenta
A histological and ultrastructural investigation of the placenta in three representatives of Eulipotyphla, that is, core insectivores, supports the widely accepted hypothesis that the stem lineage of Placentalia is characterized by an invasive, either endothelio‐ or hemochorial placentA.


Phylogenomic data analyses provide evidence that Xenarthra and Afrotheria are sister groups.
The phylogenetic analysis joined Xenarthra and Afrotheria on a common branch, Atlantogenata, and this topology was found to fit the data significantly better than the alternative trees, and exceeds by a considerable margin that of any previous study.
Housekeeping genes for phylogenetic analysis of eutherian relationships.
The analyses of the currently established sequences have helped examination of problematic parts in the eutherian tree at the same time as they caution against suggestions that have claimed that basal eutheria relationships have been conclusively settled.
Retroposon analysis and recent geological data suggest near-simultaneous divergence of the three superorders of mammals
It is proposed that near-simultaneous divisions of continents leading to isolated Africa, South America, and Laurasia caused nearly concomitant divergence of the ancient placental ancestor into 3 lineages, Afrotheria, Xenarthra, and Boreotheria, ≈120 Ma.
Relationships of Endemic African Mammals and Their Fossil Relatives Based on Morphological and Molecular Evidence
Analyses of anatomical and DNA sequence data run on a parallel supercomputer that include fossil taxa support the inclusion of tenrecs and golden moles in the Afrotheria, an endemic African clade of placental mammals, and support the position of AfroTheria as well-nested, not basal, within Placentalia.
Using genomic data to unravel the root of the placental mammal phylogeny.
The genome sequence assemblies of human, armadillo, elephant, and opossum are analyzed to identify informative coding indels that would serve as rare genomic changes to infer early events in placental mammal phylogeny and suggest Afrotheria and Xenarthra diverged from other placental mammals approximately 103 (95-114) million years ago.
Early Tertiary mammals from North Africa reinforce the molecular Afrotheria clade
New dental and postcranial evidence of Eocene stem hyrax and macroscelidid from North Africa are reported that, for the first time, provides a congruent phylogenetic view with the molecular Afrotheria clade.
Molecular evidence for multiple origins of Insectivora and for a new order of endemic African insectivore mammals.
The traditional views regarding the mammalian order Insectivora are that the group descended from a single common ancestor and that it is comprised of the following families: Soricidae (shrews),
Resolution among major placental mammal interordinal relationships with genome data imply that speciation influenced their earliest radiations
The narrow temporal window within which some placental divergences took place suggests that inconsistencies and limited resolution of the mammalian tree may have their natural explanation in speciation processes such as lineage sorting, introgression from species hybridization or hybrid speciation.
A new phylogenetic marker, apolipoprotein B, provides compelling evidence for eutherian relationships.
Afrotherian mammals: a review of current data
Molecular data suggest an African origin for Afrotheria and a long period of endemism on that continent, and paleontological data argue for the broad distribution of afrotherians during the Tertiary and do not exclude their Laurasian origin.