Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

A Jurassic acanthocephalan illuminates the origin of thorny-headed worms

Nature volume 641, pages 674–680 (2025)Cite this article

Subjects

Abstract

Acanthocephala (thorny-headed worms), characterized by the presence of an eversible proboscis with hooks, are a diverse endoparasitic group that infect a wide range of vertebrates and invertebrates1. Although long regarded as a separate phylum, they have several putative sister taxa based on morphological features, including Platyhelminthes (flatworms)2, Priapulida (penis worms)3 and Rotifera (wheel animals)4. Molecular phylogenies have instead recovered them within rotifers5,6,7,8,9,10, suggesting acanthocephalans are derived from free-living worms with a jaw apparatus (Gnathifera). Their only fossil record is Late Cretaceous eggs11, contributing limited palaeontological information to deciphering their early evolution. Here we describe an acanthocephalan body fossil, Juracanthocephalus daohugouensis gen. et. sp. nov., from the Middle Jurassic Daohugou biota of China. Juracanthocephalus shows unambiguous acanthocephalan characteristics, for example a hooked proboscis, a bursa, as well as a jaw apparatus with discrete elements that is typical of other gnathiferans. Juracanthocephalus shares features with Seisonidea (an epizoic member of Rotifera) and Acanthocephala, bridging the evolutionary gap between jawed rotifers and the obligate parasitic, jawless acanthocephalans. Our results reveal previously unrecognized ecological and morphological diversity in ancient Acanthocephala and highlight the significance of transitional fossils, revealing the origins of this highly enigmatic group of living organisms.

Access through your institution
Buy or subscribe

This is a preview of subscription content, access via your institution

Access options

Access through your institution

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Gross morphology of holotype of J. daohugouensis gen. et sp. nov., NIGP206848, and comparison with extant Acanthocephala.
Fig. 2: Proboscis and jaw apparatus of J. daohugouensis gen. et sp. nov., NIGP206848.
Fig. 3: Posterior area of J. daohugouensis gen. et sp. nov., NIGP206848.
Fig. 4: Represetiative hypotheses concerning the phylogenetic relationships of Syndermata and the phylogenetic position of J. daohugouensis.

Similar content being viewed by others

Data availability

All data analysed in this paper, including the phylogenetic datasets, are available as part of the Article, Extended Data Figs. 1–6 or the Supplementary Information. The nomenclature of J. daohugouensis gen. et sp. nov. has been registered at ZooBank (LSID, urn:lsid:zoobank.org:act:4F294930-AE20-45E4-A9E2-8FC96919B56B).

Code availability

The phylogenetic datasets and the commands necessary for executing the MrBayes, PAUP and TNT analyses are included as NEXUS and TNT formatted files in Supplementary Data 1–3.

References

  1. Kennedy, C. R. Ecology of the Acanthocephala (Cambridge Univ. Press, 2006).

  2. Van Cleave, H. J. Relationships of the Acanthocephala. Am. Nat. 75, 31–47 (1941).

    Article  Google Scholar 

  3. Conway Morris, S. & Crompton, D. W. T. The origins and evolution of the Acanthocephala. Biol. Rev. 57, 85–115 (1982).

    Article  Google Scholar 

  4. Ahlrichs, W. H. Epidermal ultrastructure of Seison nebaliae and Seison annulatus, and a comparison of epidermal structures within the Gnathifera. Zoomorphology 117, 41–48 (1997).

    Article  Google Scholar 

  5. Garey, J. R., Near, T. J., Nonnemacher, M. R. & Nadler, S. A. Molecular evidence for Acanthocephala as a subtaxon of Rotifera. J. Mol. Evol. 43, 287–292 (1996).

    Article  ADS  CAS  PubMed  Google Scholar 

  6. Herlyn, H., Piskurek, O., Schmitz, J., Ehlers, U. & Zischler, H. The syndermatan phylogeny and the evolution of acanthocephalan endoparasitism as inferred from 18S rDNA sequences. Mol. Phylogenet. Evol. 26, 155–164 (2003).

    Article  CAS  PubMed  Google Scholar 

  7. Sørensen, M. V. & Giribet, G. A modern approach to rotiferan phylogeny: combining morphological and molecular data. Mol. Phylogenet. Evol. 40, 585–608 (2006).

    Article  PubMed  Google Scholar 

  8. Wey-Fabrizius, A. R. et al. Transcriptome data reveal syndermatan relationships and suggest the evolution of endoparasitism in Acanthocephala via an epizoic stage. PLoS ONE 9, e88618 (2014).

    Article  ADS  PubMed  PubMed Central  Google Scholar 

  9. Laumer, C. E. et al. Spiralian phylogeny informs the evolution of microscopic lineages. Curr. Biol. 25, 2000–2006 (2015).

    Article  CAS  PubMed  Google Scholar 

  10. Sielaff, M. et al. Phylogeny of Syndermata (syn. Rotifera): mitochondrial gene order verifies epizoic Seisonidea as sister to endoparasitic Acanthocephala within monophyletic Hemirotifera. Mol. Phylogenet. Evol. 96, 79–92 (2016).

    Article  CAS  PubMed  Google Scholar 

  11. Cardia, D. F. F., Bertini, R. J., Camossi, L. G. & Letizio, L. A. First record of Acanthocephala parasites eggs in coprolites preliminary assigned to Crocodyliformes from the Adamantina Formation (Bauru Group, Upper Cretaceous), São Paulo, Brazil. An. Acad. Bras. Ciênc. 91, e20170848 (2019).

    Article  Google Scholar 

  12. Smith, M. R., Harvey, T. H. P. & Butterfield, N. J. The macro- and microfossil record of the Cambrian priapulid. Ottoia. Palaeontology 58, 705–721 (2015).

    Article  Google Scholar 

  13. Giribet, G. & Edgecombe, G. D. Current understanding of Ecdysozoa and its internal phylogenetic relationships. Integr. Comp. Biol. 57, 455–466 (2017).

    Article  PubMed  Google Scholar 

  14. Smith, M. R. A palaeoscolecid worm from the Burgess Shale. Palaeontology 58, 973–979 (2015).

    Article  Google Scholar 

  15. Palm, H. W. The Trypanorhyncha Diesing, 1863 (PKSPL-IPB, 2004).

  16. Wang, S. et al. High-resolution taphonomic and palaeoecological analyses of the Jurassic Yanliao Biota of the Daohugou area, northeastern China. Palaeogeogr. Palaeoclim. Palaeoecol. 530, 200–216 (2019).

    Article  ADS  Google Scholar 

  17. Yang, J., Smith, M. R., Zhang, X.-G. & Yang, X.-Y. Introvert and pharynx of Mafangscolex, a Cambrian palaeoscolecid. Geol. Mag. 157, 2044–2050 (2020).

    Article  ADS  CAS  Google Scholar 

  18. Howard, R. J., Parry, L. A., Clatworthy, I., D’Souza, L. & Edgecombe, G. D. Palaeoscolecids from the Ludlow Series of Leintwardine, Herefordshire (UK): the latest occurrence of palaeoscolecids in the fossil record. Pap. Palaeontol. 10, e1558 (2024).

    Article  Google Scholar 

  19. Luo, C. et al. Exceptional preservation of a marine tapeworm tentacle in Cretaceous amber. Geology 52, 497–501 (2024).

    Article  CAS  Google Scholar 

  20. Fonseca, M. C. G. D. et al. Acanthocephalan parasites of the flounder species Paralichthys isosceles, Paralichthys patagonicus and Xystreurys rasile from Brazil. Rev. Bras. Parasitol. V. 28, 346–359 (2019).

    Article  Google Scholar 

  21. Bekkouche, N. & Gąsiorowski, L. Careful amendment of morphological data sets improves phylogenetic frameworks: re-evaluating placement of the fossil Amiskwia sagittiformis. J. Syst. Palaeontol. 20, 1–14 (2022).

    Article  Google Scholar 

  22. Herlyn, H. in The Evolution and Fossil Record of Parasitism: Identification and Macroevolution of Parasites (eds De Baets, K. & Huntley, J. W.) 273–313 (Springer International Publishing, 2021).

  23. Ahlrichs, W. H. Zur Ultrastruktur und Phylogenie von Seison nebaliae Grube, 1859 und Seison annulatus Claus, 1876. Hypothesen zu phylogenetischen Verwandtschaftsverhältnissen innerhalb der Bilateria (Georg-August-Univ., 1995).

  24. Vasilikopoulos, A. et al. Whole-genome analyses converge to support the Hemirotifera hypothesis within Syndermata (Gnathifera). Hydrobiologia 851, 2795–2826 (2024).

    Article  ADS  Google Scholar 

  25. Melone, G., Ricci, C., Segers, H. & Wallace, R. L. Phylogenetic relationships of phylum Rotifera with emphasis on the families of Bdelloidea. Hydrobiologia 387, 101–107 (1998).

    Article  Google Scholar 

  26. Mauer, K. M. et al. Genomics and transcriptomics of epizoic Seisonidea (Rotifera, syn. Syndermata) reveal strain formation and gradual gene loss with growing ties to the host. BMC Genomics 22, 604 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Hagemann, L., Mauer, K. M., Hankeln, T., Schmidt, H. & Herlyn, H. Nuclear genome annotation of wheel animals and thorny-headed worms: inferences about the last common ancestor of Syndermata (Rotifera s.l.). Hydrobiologia 851, 2827–2844 (2023).

    Article  ADS  Google Scholar 

  28. Ferraguti, M. & Melone, G. Spermiogenesis in Seison nebaliae (Rotifera, Seisonidea): further evidence of a rotifer-acanthocephalan relationship. Tissue Cell 31, 428–440 (1999).

    Article  CAS  PubMed  Google Scholar 

  29. Struck, T. H. et al. Platyzoan paraphyly based on phylogenomic data supports a noncoelomate ancestry of Spiralia. Mol. Biol. Evol. 31, 1833–1849 (2014).

    Article  CAS  PubMed  Google Scholar 

  30. Clément, P. The phylogeny of rotifers: molecular, ultrastructural and behavioural data. Hydrobiologia 255, 527–544 (1993).

    Article  Google Scholar 

  31. Ricci, C. Are lemnisci and proboscis present in the Bdelloidea? Hydrobiologia 387, 93–96 (1998).

    Article  Google Scholar 

  32. Sørensen, M. V. On the evolution and morphology of the rotiferan trophi, with a cladistic analysis of Rotifera. J. Zool. Syst. Evol. Res. 40, 129–154 (2002).

    Article  Google Scholar 

  33. Koch, N. M. & Parry, L. A. Death is on our side: paleontological data drastically modify phylogenetic hypotheses. Syst. Biol. 69, 1052–1067 (2020).

    Article  PubMed  Google Scholar 

  34. De Baets, K., Dentzien-Dias, P., Harrison, G. W. M., Littlewood, D. T. J. & Parry, L. A. in The Evolution and Fossil Record of Parasitism: Identification and Macroevolution of Parasites (eds De Baets, K. & Huntley, J. W.) 231–271 (Springer International Publishing, 2021).

  35. Verweyen, L., Klimpel, S. & Palm, H. W. Molecular phylogeny of the Acanthocephala (class Palaeacanthocephala) with a paraphyletic assemblage of the orders Polymorphida and Echinorhynchida. PLoS ONE 6, e28285 (2011).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  36. Vinther, J. & Parry, L. A. Bilateral jaw elements in Amiskwia sagittiformis bridge the morphological gap between gnathiferans and chaetognaths. Curr. Biol. 29, 881–888 (2019).

    Article  CAS  PubMed  Google Scholar 

  37. Park, T.-Y. S. et al. A giant stem-group chaetognath. Sci. Adv. 10, eadi6678 (2024).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  38. Sullivan, C. et al. The vertebrates of the Jurassic Daohugou Biota of northeastern China. J. Vertebr. Paleontol. 34, 243–280 (2014).

    Article  Google Scholar 

  39. Hejnol, A. in Evolutionary Developmental Biology of Invertebrates 2: Lophotrochozoa (Spiralia) (ed. Wanninger, A.) 1–12 (Springer, 2015).

  40. Ricci, C., Melone, G. & Sotgia, C. Old and new data on Seisonidea (Rotifera). Hydrobiologia 255, 495–511 (1993).

    Article  Google Scholar 

  41. Haustein, T., Lawes, M., Harris, E. & Chiodini, P. L. An eye-catching acanthocephalan. Clin. Microbiol. Infec. 16, 787–788 (2010).

    Article  CAS  Google Scholar 

  42. Nickol, B. B. in Fish Diseases and Disorders, Volume 1: Protozoan and Metazoan Infections (ed. Woo, P. T. K.) 444–465 (CAB International, 2006).

  43. Al-Jahdali, M. O., Hassanine, R. M. E.-S. & Touliabah, H. E.-S. The life cycle of Sclerocollum saudii Al-Jahdali, 2010 (Acanthocephala: Palaeacanthocephala: Rhadinorhynchidae) in amphipod and fish hosts from the Red Sea. J. Helminthol. 89, 277–287 (2015).

    Article  CAS  PubMed  Google Scholar 

  44. Cong, P. et al. Host-specific infestation in early Cambrian worms. Nat. Ecol. Evol. 1, 1465–1469 (2017).

    Article  PubMed  Google Scholar 

  45. Massini, J. G., Escapa, I. H., Guido, D. M. & Channing, A. First glimpse of the silicified hot spring biota from a new Jurassic chert deposit in the Deseado Massif, Patagonia, Argentina. Ameghiniana 53, 205–230 (2016).

    Article  Google Scholar 

  46. Southcott, R. V. & Lange, R. T. Acarine and other microfossils from the Maslin Eocene, South Australia. Rec. S. Aust. Mus. 16, 1–21 (1971).

    Google Scholar 

  47. Poinar, G. O. & Ricci, C. Bdelloid rotifers in Dominican amber: evidence for parthenogenetic continuity. Experientia 48, 408–410 (1992).

    Article  Google Scholar 

  48. Waggoner, B. M. & Poinar, G. O. Fossil habrotrochid rotifers in Dominican amber. Experientia 49, 354–357 (1993).

    Article  Google Scholar 

  49. Near, T. J., Garey, J. R. & Nadler, S. A. Phylogenetic relationships of the Acanthocephala inferred from 18S ribosomal DNA sequences. Mol. Phylogenet. Evol. 10, 287–298 (1998).

    Article  CAS  PubMed  Google Scholar 

  50. Kapli, P., Yang, Z. & Telford, M. J. Phylogenetic tree building in the genomic age. Nat. Rev. Genet. 21, 428–444 (2020).

    Article  CAS  PubMed  Google Scholar 

  51. Huelsenbeck, J. P. & Ronquist, F. MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics 17, 754–755 (2001).

    Article  CAS  PubMed  Google Scholar 

  52. Lewis, P. O. A likelihood approach to estimating phylogeny from discrete morphological character data. Syst. Biol. 50, 913–925 (2001).

    Article  CAS  PubMed  Google Scholar 

  53. Swofford, D. L. PAUP*. [Phylogenetic analysis using parsimony (and other methods)] v.4 (Sinauer Associates, 2003).

  54. Goloboff, P. A. & Morales, M. E. TNT version 1.6, with a graphical interface for MacOS and Linux, including new routines in parallel. Cladistics 39, 144–153 (2023).

    Article  PubMed  Google Scholar 

Download references

Acknowledgements

We are grateful to H. Herlyn, H. Zhang, M. V. Sørensen, A. Rasnitsyn, J. Zhang and D. Zheng for helpful discussions and comments, Y. Fang for the energy-dispersive X-ray spectroscopy analyses and D. Yang for artistic reconstruction. We also thank M. Knoff for providing the image of S. sagittifer. This study was supported by the National Natural Science Foundation of China (grant nos. 42125201 and 42293280) and the Jiangsu Innovation Support Plan for International Science and Technology Cooperation Programme (BZ2023068). This paper is a contribution to the IUGS “Deep-time Digital Earth” Big Science Program, Geobiodiversity Database. L.A.P. is supported by a NERC independent research fellowship (NE/W007878/1).

Author information

Authors and Affiliations

  1. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China

    Cihang Luo, Shengyu Wang, Edmund A. Jarzembowski, Haichun Zhang & Bo Wang

  2. University of Chinese Academy of Sciences, Beijing, China

    Cihang Luo

  3. Department of Terrestrial Zoology, Entomology II, Senckenberg Research Institute and Natural History Museum, Frankfurt am Main, Germany

    Cihang Luo & Brendon E. Boudinot

  4. Department of Earth Sciences, University of Oxford, Oxford, UK

    Luke A. Parry

  5. Department of Earth Sciences, Natural History Museum, London, UK

    Edmund A. Jarzembowski

Authors
  1. Cihang Luo
    View author publications

    Search author on:PubMed Google Scholar

  2. Luke A. Parry
    View author publications

    Search author on:PubMed Google Scholar

  3. Brendon E. Boudinot
    View author publications

    Search author on:PubMed Google Scholar

  4. Shengyu Wang
    View author publications

    Search author on:PubMed Google Scholar

  5. Edmund A. Jarzembowski
    View author publications

    Search author on:PubMed Google Scholar

  6. Haichun Zhang
    View author publications

    Search author on:PubMed Google Scholar

  7. Bo Wang
    View author publications

    Search author on:PubMed Google Scholar

Contributions

B.W. designed the project. C.L., L.A.P. and B.E.B. carried out the phylogenetic analysis. S.W. conducted the SEM and energy-dispersive X-ray spectroscopy analyses. H.Z. and B.W. collected the specimen. C.L., L.A.P. and B.W. wrote the original draft with review and editing from B.E.B., S.W., E.A.J. and H.Z. All authors carried out the morphological analysis, discussed the results and approved the final manuscript.

Corresponding author

Correspondence to Bo Wang.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature thanks Tae-Yoon Park, Jakob Vinther and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended Data Fig. 1 Elemental analysis of holotype of J. daohugouensis gen. et sp. nov., NIGP206848.

a, Photograph in alcohol. b, Backscatter scanning electron (BSE) image under a scanning electronic microscope. c–h, Elemental maps of b from energy-dispersive X-ray spectroscopy. c, Overlay image of element C (green colour), O (red colour), Al (blue colour), Si (purple colour), and K (yellow colour) concentrations. d, O map. e, Al map. f, Si map. g, K map. h, Fe map. i, EDS spectrum of the complete montage. Scale bar, 2.0 mm.

Extended Data Fig. 2 Proboscis of holotype of J. daohugouensis gen. et sp. nov., NIGP206848.

a–d, Elemental maps from energy-dispersive X-ray spectroscopy. a, C map. b, O map. c, Si map. d, K map. e, Higher magnification of proboscis (dry), white arrows mark hooks. f, Higher magnification of mouth opening area (in alcohol). at, alimentary tract. All analyses were performed three times. Scale bars, 0.5 mm (a–d), 0.2 mm (e, f).

Extended Data Fig. 3 Topology from Bayesian inference phylogenetic analysis.

a, Majority-rule consensus tree including J. daohugouensis from Bayesian inference analysis (Methods). b, Majority-rule consensus tree excluding J. daohugouensis from Bayesian inference analysis (Methods). Node labels show posterior probability values.

Extended Data Fig. 4 Phylogenetic tree from strict consensus tree of parsimony analysis.

a, Strict consensus tree including J. daohugouensis of 593 most parsimonious trees (410 scores each) from PAUP parsimony analysis (Methods), CI = 0.566, RI = 0.834. b, Strict consensus tree excluding J. daohugouensis of 659 most parsimonious trees (409 scores each) from PAUP parsimony analysis (Methods), CI = 0.567, RI = 0.833. The strict consensus tree fails to resolve the relationship between Seisonidea, Rotifera and Acanthophala when Juracanthocephalus is excluded.

Extended Data Fig. 5 Phylogenetic tree from 50% majority rule bootstrap consensus tree of parsimony analysis.

a, 50% majority rule bootstrap consensus tree including J. daohugouensis from PAUP parsimony analysis (Methods). b, 50% majority rule bootstrap consensus tree excluding J. daohugouensis from PAUP parsimony analysis (Methods). Node labels indicate bootstrap support.

Extended Data Fig. 6 Full list of apomorphies of Gnathifera.

Apomorphies are optimized computationally unless followed by an asterisk, which denotes an apomorphy suggested by our results but lacking sufficient sampling to optimise computationally. The apomorphic losses of Acanthocephala are also added. The topology is derived from the strict consensus tree based on a matrix of 68 taxa and 247 characters; the non-gnathiferans were omitted for clarity but were included in the analyses in which synapomorphies were optimised; the precise systematic position of Gnathostomulida has not been recovered in the strict consensus tree, but it is widely considered as the sister group of other gnathiferans. Yellow rectangles represent characters associated with jaw apparatus, green rectangles represent characters associated with gut (including mouth and anus), red rectangles represent characters associated with body shape, and grey rectangles represent characters associated with other body structures. Characters that can be observed in J. daohugouensis are in red colour, otherwise in black. Cross indicates extinct taxa.

Supplementary information

Supplementary Note 1

Characters used in phylogenetic analysis.

Reporting Summary

Supplementary Data 1

Matrix of the Bayesian approach.

Supplementary Data 2

Matrix of parsimony analyses using PAUP.

Supplementary Data 3

Matrix of parsimony analyses using TNT.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Luo, C., Parry, L.A., Boudinot, B.E. et al. A Jurassic acanthocephalan illuminates the origin of thorny-headed worms. Nature 641, 674–680 (2025). https://doi.org/10.1038/s41586-025-08830-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue date:

  • DOI: https://doi.org/10.1038/s41586-025-08830-5

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing