The DOI matches its Crossref record; 87 of the 88 references it cites were found in a registry or an index.
Acoel development supports a simple planula-like urbilaterian
Open accessAbstract
Molecular approaches to the study of development and evolution have had profound effects on our understanding of the nature of the evolutionary process. Developmental biologists became intoxicated with fanciful notions of reconstructing genetic pathways of morphogenesis while evolutionary biologists were sobered by the fallacy of reconstructing organismal relationships along increasing grades of morphological complexity. Increased taxon sampling and improvements in analytical techniques are providing a new approach and are forcing biologists to move past historical biases to allow more accurate mapping of morphological and developmental characters through evolutionary time. Here, we discuss the possible developmental and morphological features of the ‘urbilaterian’, the triploblastic animal with anterior-posterior and dorsoventral axes and predecessor of the protostome–deuterostome ancestor. We argue that this animal, with features resembling acoelomorph flatworms, was far simpler morphologically than the protostome–deuterostome ancestor despite possessing a nearly complete eubilaterian genome. We show that the deployment of some genes expected to pattern the protostome–deuterostome ancestor is not deployed in acoels in the predicted manner and thus might have been co-opted after the evolution of the urbilaterian. We also identify the developmental changes related to gastrulation that gave rise to the urbilaterian from a simpler cnidarian-like ancestor.
Overview
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“in development of the most basal cnidarian clade, anthozoans, regulatory genes are expressed in bilateral axial patterns that indicate an underlying set of bilateral regulatory states.”
From An integrated view of precambrian eumetazoan evolution (2009) · cites this paper as Hejnol and Martindale 2008
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Citations
Cites
Microscopic anatomy of invertebrates
Harrison, F. W. (1991) · Wiley-Liss eBooks · Cited by 2,736
Phylogenetic Perspectives in Innate Immunity
Hoffmann, J. A., Kafatos, F. C., Janeway, C. A., & Ezekowitz, R. A. B. (1999) · Science · doi:10.1126/science.284.5418.1313 · Cited by 2,524
Sea Anemone Genome Reveals Ancestral Eumetazoan Gene Repertoire and Genomic Organization
Putnam, N. H., Srivastava, M., Hellsten, U., Dirks, B., Chapman, J., Salamov, A., Terry, A., Shapiro, H., Lindquist, E., Kapitonov, V. V., et al. (2007) · Science · doi:10.1126/science.1139158 · Cited by 1,555
Self-citationMechanisms of germ cell specification across the metazoans: epigenesis and preformation
Extavour, C. G. M., & Akam, M. E. (2003) · Development · doi:10.1242/dev.00804 · Cited by 800
A common plan for dorsoventral patterning in Bilateria
De Robertis, E. M., & Sasai, Y. (1996) · Nature · doi:10.1038/380037a0 · Cited by 780
Pax 6: mastering eye morphogenesis and eye evolution
Gehring, W. J., & Ikeo, K. (1999) · Trends in Genetics · doi:10.1016/s0168-9525(99)01776-x · Cited by 758
The zootype and the phylotypic stage
Slack, J. M. W., Holland, P. W. H., & Graham, C. F. (1993) · Nature · doi:10.1038/361490a0 · Cited by 699
NK-2Homeobox Genes and Heart Development
Harvey, R. P. (1996) · Developmental Biology · doi:10.1006/dbio.1996.0212 · Cited by 579
Deuterostome phylogeny reveals monophyletic chordates and the new phylum Xenoturbellida
Bourlat, S. J., Juliusdottir, T., Lowe, C. J., Freeman, R. M., Aronowicz, J., Kirschner, M., Lander, E. S., Thorndyke, M. C., Nakano, H., Kohn, A. B., et al. (2006) · Nature · doi:10.1038/nature05241 · Cited by 568
Denes, A. S., Jékely, G., Steinmetz, P. R. H., Raible, F., Snyman, H., Prud'homme, B., Ferrier, D. E. K., Balavoine, G., & Arendt, D. (2007) · Cell · doi:10.1016/j.cell.2007.02.040 · Cited by 480
Research works printed but not linked: 2
- Arendt D, 2004, Gastrulation, 679
- Remane A, 1963, The lower Metazoa, 78
Cited by
Sorted by citations
Items 101–161 of 161
Lee, C. A., Brown, J. W., & Gillette, R. (2023) · Journal of Neuroscience · doi:10.1523/jneurosci.1386-22.2023 · Cited by 6
Shigeno, S. (2017) · Diversity and Commonality in Animals · doi:10.1007/978-4-431-56469-0_19 · Cited by 6
(2009) · doi:10.1093/acprof:oso/9780199549429.001.0001 · Cited by 7
The earliest fossil record of the animals and its significance
Budd, G. E. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0001 · Cited by 6
Redefining Stem Cells and Assembling Germ Plasm
Srouji, J. R., & Extavour, C. G. M. (2010) · Science Publishers eBooks · doi:10.1201/b10425-20 · Cited by 5
The evolution of the animals: introduction to a Linnean tercentenary celebration
Telford, M. J., & Littlewood, D. T. J. (2008) · Philosophical Transactions of the Royal Society B Biological Sciences · doi:10.1098/rstb.2007.2231 · Cited by 5
A history of Evo-Devo research in Spain
Baguñ, J. (2009) · The International Journal of Developmental Biology · doi:10.1387/ijdb.072427jb · Cited by 5
Peel, A. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0016 · Cited by 4
Ligrone, R. (2019) · Springer eBooks · doi:10.1007/978-3-030-16057-9_10 · Cited by 3
A proposal in relation to a genetic control of lifespan in mammals
Neill, D. (2010) · Ageing Research Reviews · doi:10.1016/j.arr.2010.05.004 · Cited by 3
The origins and evolution of the Ecdysozoa
Telford, M. J., Bourlat, S. J., Economou, A. D., Papillon, D., & Rota‐Stabelli, O. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0008 · Cited by 4
Origins of metazoan body plans: the larval revolution
Raff, R. A. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0005 · Cited by 3
Acoel single-cell transcriptomics: cell-type analysis of a deep branching bilaterianPreprint
Duruz, J., Kaltenrieder, C., Ladurner, P., Bruggmann, R., Martı́nez, P., & Sprecher, S. G. (2020) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2020.07.10.196782 · Cited by 3
Beyond Individuality: Developmental and Evolutionary Deviations in Animal Body Plans
Miura, T., & Oguchi, K. (2025) · ZOOLOGICAL SCIENCE · doi:10.2108/zs250076 · Cited by 2
Children of time: the geological recency of intelligence and its implications for SETI
Mussini, G. (2023) · International Journal of Astrobiology · doi:10.1017/s1473550423000253 · Cited by 2
Reassembling animal evolution: a four-dimensional puzzle
Telford, M. J., Timothy, D. J., & Littlewood, D. T. J. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0018 · Cited by 2
Beldade, P., & Saenko, S. V. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0017 · Cited by 2
Beyond Congruence: Evidential Integration and Inferring the Best Evolutionary ScenarioPreprint
Kourki, A. N. (2021) · Preprints.org · doi:10.20944/preprints202105.0767.v1 · Cited by 2
Life-stage-specific specialities in the cell atlases of the Clytia hemisphaerica planula and medusaPreprint
Ferraioli, A., Ramon-Mateu, J., Meynadier, M., Lamonerie, T., Pagnotta, S., Chevalier, S., Iglesias, M., Najle, S. R., Sebé-Pedrós, A., Arguel, M., et al. (2026) · eLife · doi:10.64898/2026.02.16.705741 · Cited by 2
Distinctive spermiogenesis in Aplacophora (Mollusca) has phylogenetic implications
Buckland‐Nicks, J. A., & Hodgson, A. N. (2024) · Zoomorphology · doi:10.1007/s00435-024-00688-x · Cited by 1
Protostomia and Deuterostomia: Do They Exist?
Malakhov, V. V., & Ezhova, O. V. (2025) · Paleontological Journal · doi:10.1134/s003103012560074x · Cited by 1
What is Evo-Devo and Why is it Important?
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.003 · Cited by 1
Boore, J. L., & Fuerstenberg, S. I. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0013 · Cited by 1
The animal in the genome: comparative genomics and evolution
Copley, R. R. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0014 · Cited by 1
Mori, S., Kobayashi, A., Sakamoto, H., Hamada, M., Sakamoto, T., & Nakamura, R. (2024) · Biophysics and Physicobiology · doi:10.2142/biophysico.bppb-v21.s012 · Cited by 1
Distributed neural computation and the evolution of the first brainsPreprint
Chandra, V., Nejad, M. R., Kann, A. P., Salem, A., Hill, K. A. P., Schalek, R., Lichtman, J., Mahadevan, L., & Srivastava, M. (2025) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2025.10.03.680388 · Cited by 2
Filogènia Molecular dels Bilaterals: una aproximació multigènica
Montserrat, J. P. (2008) · LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas)
The evolution of metazoan GATA transcription factors
Gillis, W. J. (2008) · Scholars' Bank (University of Oregon)
Krämer-Eis, A., Luca Ferretti, A., Schiffer, P. H., Heger, P., & Wiehe, T. (2016) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/041806
Krämer-Eis, A., Luca Ferretti, A., Schiffer, P. H., Heger, P., & Wiehe, T. (2016)
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.011
The Evolutionary Origins of Body Plans
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.009
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.006
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.004
Evolutionary and Developmental Essentials
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.005
Summary of Common Misunderstandings
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.013
The Evolution of Variations on a Theme
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.007
Body-Plan Features and Toolkit Genes
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.010
Arthur, W. (2021) · doi:10.1017/9781108873130.002
Arthur, W. (2021) · doi:10.1017/9781108873130.015
Arthur, W. (2021) · doi:10.1017/9781108873130.001
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.014
The Evolutionary Origins of Themes and Novelties
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.008
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.012
Lowe, C. J. (2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.003.0010
Arthur, W. (2021) · Cambridge University Press eBooks · doi:10.1017/9781108873130.016
(2016) · Elsevier eBooks · doi:10.1016/b978-0-12-802996-1.16001-8
(2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.002.0004
(2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.002.0003
(2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.002.0007
(2009) · Oxford University Press eBooks · doi:10.1093/acprof:oso/9780199549429.002.0008
Beyond congruence: evidential integration and inferring the best evolutionary scenario
Kourki, A. N. (2022) · Biology & Philosophy · doi:10.1007/s10539-022-09867-w
Basic and applied biology of the photosynthetic flatworm Symsagittifera roscoffensis
Thomas, N. J. (2024) · Cronfa (Swansea University) · doi:10.23889/suthesis.67067
Molnar, N., Capik, A., Ishak, A., Maglakelidze, N., Pasick, L. J., Reneker, B., Volino, A., & O'Connell, M. L. (2025) · Zygote · doi:10.1017/s0967199425000024
Origins and Diversification of Marine Invertebrate Larvae
Boyle, M. J. (2025) · Elsevier eBooks · doi:10.1016/b978-0-08-102871-1.00029-4
Characterization of the Hox patterning genes in acoel flatworms
González, E. M. (2010) · Tesis Doctorals en Xarxa (Consorci de Serveis Universitaris de Catalunya)
Parekh, R., Hermine, C., Otomo, Y., & Miura, T. (2025) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.64898/2025.12.15.692464
ParaHox Genes Revisited: From Gut Patterning to Integrated Axial and Neural Organization in Rotifera
Fröbius, A. C., Welch, D. B. M., & Herlyn, H. (2026) · Journal of Experimental Zoology Part B Molecular and Developmental Evolution · doi:10.1002/jez.b.70019
Evolution of the retinoic acid receptor
Gutierrez-Mazariegos, J. (2014) · theses.fr (ABES) · doi:10.70675/361e9701z45c1z4914z9bc7z9d25e1c92665
Buckenmeyer, A., Abalde, S., Ryan, J. F., & Jondelius, U. (2026) · Genome Biology and Evolution · doi:10.1093/gbe/evag094
Morphology and Development of Reproductive Organs in the Acoel Hofstenia atroviridis
Parekh, R., Hermine, C., Otomo, Y., & Miura, T. (2026) · ZOOLOGICAL SCIENCE · doi:10.2108/zs250119
Metadata
- Authors
- Hejnol, A., & Martindale, M. Q.
- Affiliations
- University of Hawaiʻi at Mānoa (US)
- Venue
- Philosophical Transactions of the Royal Society B: Biological Sciences
- Publisher
- The Royal Society
- Published
- 2008-01-11
- Volume
- 363
- Issue
- 1496
- Pages
- 1493-1501
- ISSN
- 0962-8436 (ISSN-L)
- 1471-2970
- PMC
- PMC2614228
- OpenAlex
- W2127207904
- Cited by
- 161
- References
- 88
- Citations by year
- 2026: 4 · 2025: 6 · 2024: 5 · 2023: 2 · 2022: 6 · 2021: 21 · 2020: 4 · 2019: 5 · 2018: 7 · 2017: 3 · 2016: 7 · 2015: 11 · 2014: 7 · 2013: 9 · 2012: 5
- FWCI
- 1.52
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Philosophical Transactions of the Royal Society B Biological Sciences (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- National Science Foundation
- Deutsche Forschungsgemeinschaft
- Topics
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Developmental Biology and Gene Regulation
- Life Sciences › Agricultural and Biological Sciences › Animal Science and Zoology › Marine Invertebrate Physiology and Ecology
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Planarian Biology and Electrostimulation
- Keywords
- acoels, gene co-option, gastrulation, morphological complexity, evolutionary developmental biology, Platyhelminthes
- MeSH terms
- Animals, Biological Evolution, Female, Male, Models, Biological, Phylogeny, Platyhelminths, Developmental Biology, Evolution, Molecular, Body Patterning, Gastrulation
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
