The new framework for understanding placental mammal evolution.
Abstract: 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) the position of bats within laurasiatheres, of sea cows and aardvarks within afrotheres, and of dermopterans within euarchontoglires. A variety of names for sub-clades within the new placental mammal tree have been proposed, not all of which follow conventions regarding priority and stability. More importantly, the new phylogenetic framework enables the formulation of new hypotheses and testing thereof, for example regarding the possible developmental dichotomy that seems to distinguish members of the newly identified southern and northern radiations of living placental mammals.
Publication Date: 2009-07-08 PubMed ID: 19582725DOI: 10.1002/bies.200900053Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
- Review
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research article presents a new theoretical framework for understanding the evolutionary relationships among living placental mammals, highlighting a more stable tree of descent compared to previous hypotheses. Still, certain areas of uncertainty persist, including the origin of the placental root and the exact positioning of some species within their major groups.
Evolving Understanding of Placental Mammal Evolution
In the body of the paper, the authors discuss the development and strengthening of a new hypothesis regarding the common descent patterns among living placental mammals, which includes species like elephants, horses, humans, and many others. These mammals are categorized into four major groups:
- Afrotheres: This group includes aardvarks, elephants, and sea cows.
- Xenarthrans: This group consists of anteaters and sloths.
- Laurasiatheres: This group encompasses horses, shrews, and potentially bats.
- Euarchontoglires: This group includes humans, rodents, and possibly dermopterans.
Compared to previous hypotheses, the researchers found this tree of descent to be remarkably more stable.
Uncertainties in the New Framework
Despite the promise shown by this new hypothesis, the authors acknowledged there remain uncertainties. These included determining the location of the placental root—the point from which all placental mammals evolved. The exact positions of sea cows and aardvarks within afrotheres, bats within laurasiatheres, and dermopterans within euarchontoglires were also areas of uncertainty.
Implications of the New Phylogenetic Framework
The authors not only proposed a new rubric for understanding the nomenclature used within the phylogenetic tree but also appreciated the potential of this new framework in enabling the formulation and testing of new hypotheses. For instance, this framework could explore the developmental dichotomy that appears to differentiate members of the newly identified southern and northern radiations of living placental mammals.
In conclusion, this research presented an evolved understanding of placental mammal evolution, acknowledging the existing uncertainties, and pointing towards new directions for further study.
Cite This Article
APA
Asher RJ, Bennett N, Lehmann T.
(2009).
The new framework for understanding placental mammal evolution.
Bioessays, 31(8), 853-864.
https://doi.org/10.1002/bies.200900053 Publication
Researcher Affiliations
- Department of Zoology, University of Cambridge, Downing St., Cambridge CB23EJ, UK. r.asher@zoo.cam.ac.uk
MeSH Terms
- Animals
- Biological Evolution
- Dentition
- Female
- Mammals / classification
- Mammals / physiology
- Phylogeny
- Placenta / physiology
- Pregnancy
- Spine / pathology
Citations
This article has been cited 34 times.- Li Y, Brinkworth A, Green E, Oyston J, Wills M, Ruta M. Divergent vertebral formulae shape the evolution of axial complexity in mammals.. Nat Ecol Evol 2023 Mar;7(3):367-381.
- Oyston JW, Wilkinson M, Ruta M, Wills MA. Molecular phylogenies map to biogeography better than morphological ones.. Commun Biol 2022 May 31;5(1):521.
- Hautier L, Tabuce R, Mourlam MJ, Kassegne KE, Amoudji YZ, Orliac M, Quillévéré F, Charruault AL, Johnson AKC, Guinot G. New Middle Eocene proboscidean from Togo illuminates the early evolution of the elephantiform-like dental pattern.. Proc Biol Sci 2021 Oct 13;288(1960):20211439.
- Asher RJ, Smith MR. Phylogenetic Signal and Bias in Paleontology.. Syst Biol 2022 Jun 16;71(4):986-1008.
- Nishimaki T, Sato K. P*R*O*P: a web application to perform phylogenetic analysis considering the effect of gaps.. BMC Bioinformatics 2021 Jan 30;22(1):36.
- López-Torres S, Bertrand OC, Lang MM, Silcox MT, Fostowicz-Frelik Ł. Cranial endocast of the stem lagomorph Megalagus and brain structure of basal Euarchontoglires.. Proc Biol Sci 2020 Jun 24;287(1929):20200665.
- Rotwein P, Baral K. Zmat2 in mammals: conservation and diversification among genes and Pseudogenes.. BMC Genomics 2020 Jan 31;21(1):113.
- Baral K, Rotwein P. The insulin-like growth factor 2 gene in mammals: Organizational complexity within a conserved locus.. PLoS One 2019;14(6):e0219155.
- Beck RMD, Baillie C. Improvements in the fossil record may largely resolve current conflicts between morphological and molecular estimates of mammal phylogeny.. Proc Biol Sci 2018 Dec 19;285(1893):20181632.
- Montañez-Rivera I, Nyakatura JA, Amson E. Bone cortical compactness in 'tree sloths' reflects convergent evolution.. J Anat 2018 Nov;233(5):580-591.
- Sharma V, Lehmann T, Stuckas H, Funke L, Hiller M. Loss of RXFP2 and INSL3 genes in Afrotheria shows that testicular descent is the ancestral condition in placental mammals.. PLoS Biol 2018 Jun;16(6):e2005293.
- Liu L, Zhang J, Rheindt FE, Lei F, Qu Y, Wang Y, Zhang Y, Sullivan C, Nie W, Wang J, Yang F, Chen J, Edwards SV, Meng J, Wu S. Genomic evidence reveals a radiation of placental mammals uninterrupted by the KPg boundary.. Proc Natl Acad Sci U S A 2017 Aug 29;114(35):E7282-E7290.
- Sánchez-Villagra MR, Forasiepi AM. On the development of the chondrocranium and the histological anatomy of the head in perinatal stages of marsupial mammals.. Zoological Lett 2017;3:1.
- Bianchetti L, Tarabay Y, Lecompte O, Stote R, Poch O, Dejaegere A, Viville S. Tex19 and Sectm1 concordant molecular phylogenies support co-evolution of both eutherian-specific genes.. BMC Evol Biol 2015 Oct 12;15:222.
- Buckley M. Ancient collagen reveals evolutionary history of the endemic South American 'ungulates'.. Proc Biol Sci 2015 May 7;282(1806):20142671.
- Beck RM, Lee MS. Ancient dates or accelerated rates? Morphological clocks and the antiquity of placental mammals.. Proc Biol Sci 2014 Oct 22;281(1793).
- Ciancio MR, Vieytes EC, Carlini AA. When xenarthrans had enamel: insights on the evolution of their hypsodonty and paleontological support for independent evolution in armadillos.. Naturwissenschaften 2014 Sep;101(9):715-25.
- Karunakaran MM, Göbel TW, Starick L, Walter L, Herrmann T. Vγ9 and Vδ2 T cell antigen receptor genes and butyrophilin 3 (BTN3) emerged with placental mammals and are concomitantly preserved in selected species like alpaca (Vicugna pacos).. Immunogenetics 2014 Apr;66(4):243-54.
- Straehl FR, Scheyer TM, Forasiepi AM, MacPhee RD, Sánchez-Villagra MR. Evolutionary patterns of bone histology and bone compactness in xenarthran mammal long bones.. PLoS One 2013;8(7):e69275.
- Zhuang J, Stoelzel CR, Bereshpolova Y, Huff JM, Hei X, Alonso JM, Swadlow HA. Layer 4 in primary visual cortex of the awake rabbit: contrasting properties of simple cells and putative feedforward inhibitory interneurons.. J Neurosci 2013 Jul 10;33(28):11372-89.
- Kaufman JA, Turner GH, Holroyd PA, Rovero F, Grossman A. Brain volume of the newly-discovered species Rhynchocyon udzungwensis (Mammalia: Afrotheria: Macroscelidea): implications for encephalization in sengis.. PLoS One 2013;8(3):e58667.
- Song S, Liu L, Edwards SV, Wu S. Resolving conflict in eutherian mammal phylogeny using phylogenomics and the multispecies coalescent model.. Proc Natl Acad Sci U S A 2012 Sep 11;109(37):14942-7.
- Billet G, Hautier L, Asher RJ, Schwarz C, Crumpton N, Martin T, Ruf I. High morphological variation of vestibular system accompanies slow and infrequent locomotion in three-toed sloths.. Proc Biol Sci 2012 Oct 7;279(1744):3932-9.
- Pointer MA, Kamilar JM, Warmuth V, Chester SG, Delsuc F, Mundy NI, Asher RJ, Bradley BJ. RUNX2 tandem repeats and the evolution of facial length in placental mammals.. BMC Evol Biol 2012 Jun 28;12:103.
- Siniza S, Lupiañez DG, Jiménez R, Zeller U. Morphology and ultrastructure of the chorioallantoic placenta of the Iberian mole (Talpa occidentalis) with special reference to heterophagous areolas and the nature of interhaemal barrier.. J Anat 2012 Aug;221(2):164-73.
- Coolen A, Hoffmann K, Barf RP, Fuchs E, Meerlo P. Telemetric study of sleep architecture and sleep homeostasis in the day-active tree shrew Tupaia belangeri.. Sleep 2012 Jun 1;35(6):879-88.
- Werneburg I, Tzika AC, Hautier L, Asher RJ, Milinkovitch MC, Sánchez-Villagra MR. Development and embryonic staging in non-model organisms: the case of an afrotherian mammal.. J Anat 2013 Jan;222(1):2-18.
- Parham JF, Donoghue PC, Bell CJ, Calway TD, Head JJ, Holroyd PA, Inoue JG, Irmis RB, Joyce WG, Ksepka DT, Patané JS, Smith ND, Tarver JE, van Tuinen M, Yang Z, Angielczyk KD, Greenwood JM, Hipsley CA, Jacobs L, Makovicky PJ, Müller J, Smith KT, Theodor JM, Warnock RC, Benton MJ. Best practices for justifying fossil calibrations.. Syst Biol 2012 Mar;61(2):346-59.
- Gracheva EO, Cordero-Morales JF, González-Carcacía JA, Ingolia NT, Manno C, Aranguren CI, Weissman JS, Julius D. Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats.. Nature 2011 Aug 3;476(7358):88-91.
- Billet G, Martin T. No evidence for an afrotherian-like delayed dental eruption in South American notoungulates.. Naturwissenschaften 2011 Jun;98(6):509-17.
- Hautier L, Weisbecker V, Sánchez-Villagra MR, Goswami A, Asher RJ. Skeletal development in sloths and the evolution of mammalian vertebral patterning.. Proc Natl Acad Sci U S A 2010 Nov 2;107(44):18903-8.
- Asher RJ, Helgen KM. Nomenclature and placental mammal phylogeny.. BMC Evol Biol 2010 Apr 20;10:102.
- Asher RJ, Maree S, Bronner G, Bennett NC, Bloomer P, Czechowski P, Meyer M, Hofreiter M. A phylogenetic estimate for golden moles (Mammalia, Afrotheria, Chrysochloridae).. BMC Evol Biol 2010 Mar 9;10:69.
- Knabe W, Obermayer B, Kuhn HJ, Brunnett G, Washausen S. Apoptosis and proliferation in the trigeminal placode.. Brain Struct Funct 2009 Dec;214(1):49-65.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
