Patterns of floral turnover and plant-insect interactions through the Guadalupian-Lopingian biotic crisis

Project overview

Project period: 2023 - 2026

Participating departments from the museum: Paleobiology

This project will resolve the patterns of extinction and recovery of plant groups and their arthropod herbivores across the Guadalupian-Lopingian (middle-upper Permian) boundary—one of the most neglected biotic crises in Earth’s history.

Analyses of diagnostic feeding and egg-laying traces enable patterns of plant utilization by terrestrial arthropods to be charted through this extinction event. The study will utilize novel X-ray and fluorescence microscopy techniques and globally unique fossil assemblages from polar to equatorial paleolatitudes to provide unparalleled insights into continental ecosystem changes through the critical interval leading up to the end-Permian mass extinction.

This project will chart the changes in key terrestrial arthropod feeding strategies and document how plants responded to insect attack over evolutionary time scales. The results will elucidate the evolution of herbivory, parasitism, saprotrophy, detritivory and plant defences immediately prior to Earth’s greatest biotic crisis.

Project description

This study addresses five key questions related to the evolution, extinction and interactions of plants and insects during the final 15 million years of the Paleozoic using diverse techniques.

Did plant diversity and representation change across the end-Guadalupian event? Since the record of turnover among plants in continental ecosystems for this event has been little studied, this project will provide crucial data for changes in taxon richness, intra-order diversity, and group representation on land.

Are plant-arthropod damage traces informative of insect diversity and herbivory through time? Since insect body fossils are scarce, trace fossils on leaves and other plant organs arguably provide the best means of evaluating insect feeding-guild diversity for the middle–late Permian. In some cases, specific arthropod taxa can be linked to the traces based on diagnostic damage scar or coprolite form. This project will examine high-quality fossil assemblages through the critical 15-Myr interval from the mid-Guadalupian to end of the Permian (267–252 Ma: (Tables 1, 2; Figs 7, 8). Each assemblage will be surveyed for damage diversity, abundance, host plants, and plant responses, enabling assessment of how herbivore diversity/guild representation fared across the critical EGE and the lead-up to the end-Permian extinction.

How did component communities respond to biotic crises? Permian temperate and tropical forests were dominated by very different plants (Glossopteridales-Cordaitales in the south, and Voltziales-Gigantopteridales in the tropics). This project will study biotic associations linked to the dominant plant groups and assess whether communities collapsed as a whole during crises, or whether arthropods were able to switch to new hosts with the demise of their host plants.

Can borings in fossil wood inform about biotic shifts in guild dominance? Some have argued that wood-boring guilds fundamentally shifted in the Triassic: earlier examples being dominated by oribatid mites and later examples by insects. However, few Permian wood assemblages have been systematically analysed for arthropod damage. This project will evaluate wood-boring strategies based on woods from successive Australian–Antarctic units.

Can permineralized remains reveal parasitism/pathogen strategies on woody plants? Few studies have targeted certain invertebrate life strategies (e.g. gall-producers and fungivores) that are important parasites and pathogen vectors in modern ecosystems. Preliminary data show galls and fungi to be common in Permian silicified woods of Gondwana. Investigations of these fossils via thin-sectioning and tomography offer the potential to reveal the ecology of multitrophic (plant-fungal-arthropod) interactions.

Can coprolites reveal guild diversification in terrestrial herbivory through time? Microcoprolites are an under-appreciated resource in paleoecology. Bulk acid-maceration of plant-rich strata yields a wealth of fossil faecal pellets that can be used to identify diverse feeding strategies not easily detected from plant or insect macrofossils. Strategies such as palynophagy, fungivory, and saprophagy are readily detectable from microcoprolites, and their quantitative analysis through the middle to late Permian will gauge the relative success of generalist vs specialist herbivores.

Funding

• Vetenskapsrådet project 2022-03920 https://www.vr.se/

Selected publications

• Agnihotri, D., Srivastava, A. & McLoughlin, S. (2025). Satpuraphyllum furcatum—a new genus and species of Peltaspermales foliage from the mid-Permian Barakar Formation of India. Alcheringa 49, 40–50. https://doi.org/10.1080/03115518.2024.2415097 External link.
• Coiro, M., McLoughlin, S., Steinthorsdottir, M., Vajda, V., Fabrikant, D. & Seyfullah, L.J., (2024). Parallel evolution of angiosperm-like venation in Peltaspermales: a reinvestigation of Furcula. New Phytologist 242, 2845–2856. https://doi.org/10.1111/nph.19726 External link.
• Feng, Z., Sui, Q., Guo, Y. & McLoughlin, S. (2023). Specialized herbivory in fossil leaves reveals multi-evolutionary origins of nyctinasty. Current Biology 33, 720-726. https://doi.org/10.1016/j.cub.2022.12.043 External link.
• Fielding, C.R., McLoughlin, S., Mays, C., Tevyaw, A.P., Frank, T.D., (2025). Fluvial architectural style and stacking patterns in a high-accommodation coal-bearing succession: the upper Permian Newcastle Coal Measures, eastern Australia. International Journal of Coal Geology 307, 104829 https://doi.org/10.1016/j.coal.2025.104829 External link.
• Fielding, C.R., Bryan, S.E., Crowley, J.L., Frank, T.D., Hren, M.T., Mays, C., McLoughlin, S., Shen, J., Wagner, P.J., Winguth, A., Winguth, C., (2023). A multidisciplinary approach to resolving the end-Guadalupian extinction. Evolving Earth 1, 100014. https://doi.org/10.1016/j.eve.2023.100014 External link.
• McLoughlin, S., Shevchuk, O.A., Windell, M.M. and Slater, B.J. (2024). Evidence for saprotrophic digestion of glossopterid pollen from Permian silicified peats of Antarctica. Grana 63, 3–15. https://doi.org/10.1080/00173134.2024.2312610 External link.
• McLoughlin, S. & Santos, A.A., (2024). Excavating the fossil record for evidence of leaf-mining. New Phytologist 242, 2391–2393. https://doi.org/10.1111/nph.19652 External link.
• McLoughlin, S., Prevec, R., Cariglino, B. & Philippe, M., (2024). Revision of Halle’s Permian plant fossils from the Falkland (Malvinas) Islands. Palaeontologia Africana 58, 53–93. https://hdl.handle.net/10539/43014 External link.
• McLoughlin, S., Santos, A.A., Donaldson, S., Pott, C., and McCurry, M., (2024). Termite activity in the mid-Cretaceous of Australia. Palaeontologia Electronica, 27(3):a48. https://doi.org/10.26879/1420 External link.
• McLoughlin, S. & Nagalingum, N.S., (2025). Seedless Land Plants: Fossil Record, Evolution and Diversification. Encyclopedia of Evolutionary Biology, 2nd Edition. Reference Module in Life Sciences. Elsevier, Amsterdam. 22 pp. https://doi.org/10.1016/B978-0-443-15750-9.00055-0 External link.
• Molina-Solís, A., Cleal, C.J., Santos, A.A., McLoughlin, S., Diez, J.B., Cascales-Miñana, B., (2026). Resource partitioning and modernization of arthropod feeding strategies on Pennsylvanian medullosalean foliage from the Nord-Pas-de-Calais Coalfield, France. Palaeogeography, Palaeoclimatology, Palaeoecology 685, 113517. https://doi.org/10.1016/j.palaeo.2025.113517 External link.
• Santos, A.A., Wappler, T. & McLoughlin, S. (2024). Earliest evidence of granivory from China (Shanxi Formation) points to seeds as a food source and nursing habitat for insects in the earliest Permian humid tropical forests of Cathaysia. Plos One 19(10): e0311737. https://doi.org/10.1371/journal.pone.0311737 External link.
• Santos, A.A., Rodríguez-Barreiro I., McLoughlin, S., Pons, D., Valenzuela-Ríos, J.I., Diez, J.B., (2024). Plant colonization of isolated palaeoecosystems: palynology of a Middle Jurassic extinct volcanic island (Camarena, eastern Spain). Palaeogeography, Palaeoclimatology, Palaeoecology 639, 112081. https://doi.org/10.1016/j.palaeo.2024.112081 External link.
• Santos, A.A., Dunlop, J.A., Hernández-Orúe, A., McLoughlin, S., Diez, J.B. & Selden, P.A., (2026). Trigonotarbids “hidden” in plant debris from a Late Pennsylvanian tropical forest at El Bierzo, Castilla y León Spain. PalZ 99, 567 – 580. https://doi.org/10.1007/s12542-025-00745-w External link.
• Santos, A.A., McLoughlin, S., Mottequin, B., Robin, N. & Nel, A., (2025). Old collections, new taxa: late Carboniferous (Moscovian) roachoids (stem group Dictyoptera) among plants with insect interactions from the Benxi Formation, China, stored in European museums. Palaeoentomology 47–72. https://doi.org/10.11646/palaeoentomology.8.1.7 External link.
• Santos, A.A., Hernández-Orúe, A., Peñalver, E., McLoughlin, S., Diez, J.B. & Nel, A., (2025). First Iberian aspidothoracid megasecopteran insect and associated plants evidencing herbivory in a tropical Carboniferous forest from León, Spain. Acta Palaeontologia Polonica 70 (1), 2025: 115–124 doi:10.4202/app.01203.2024
• Santos, A.A., McLoughlin, S. & Nel, A., (2025). A new representative of the roachoid family Necymylacridae (stem group Dictyoptera) and associated vegetation with insect interactions from the Shanxi Formation (lower Permian), China. Palaeoworld 34, 200991. https://doi.org/10.1016/j.palwor.2025.200991 External link.
• Santos, A.A., McLoughlin, S., Villanueva-Amadoz, U., Rubalcaba-Knoth, M., Hernández-Damian, A.L., Sergio Cevallos-Ferriz, S., (2024). Plant-insect interactions in the mid-Cretaceous paleotropical El Chango Lagerstätte (Cintalapa Fm., Mexico)—patterns of herbivory during the Angiosperm Terrestrial Revolution. Frontiers in Ecology and Evolution 12, 1381539. https://doi.org/10.3389/fevo.2024.1381539 External link.
• Sui, Q., Sheng, Z.-H., Yang, J.-Y., Guo, Y., McLoughlin, S. & Feng, Z. (2023). Two new isoetalean (Lycopsida) megaspore species representing the earliest occurrence of Henrisporites from upper Permian strata of Southwest China. Review of Paleobotany and Palynology 314, 104894 https://doi.org/10.1016/j.revpalbo.2023.104894 External link.
• Turner, H.-A., McLoughlin, S. & Mays, C., (2024). Comprehensive survey of Early to Middle Triassic Gondwanan floras reveals under-representation of plant–arthropod interactions. Frontiers in Ecology and Evolution 12, 1419254. https://doi.org/10.3389/fevo.2024.1419254 External link.
• Vajda, V. & McLoughlin, S., (2025). Devon till perm – från skog till öken. In Sveriges geologi: en resa i tid och rum. Vajda, V. & Wohlfarth, B. (eds), Daidalos, Gothenburg, pp. 350–371.
• Vajda, V., McLoughlin, S., Slater, S.M., Gustafsson, O. & Rasmusson, A.G., (2023). The ‘seed-fern’ Lepidopteris mass-produced the abnormal pollen Ricciisporites during the end-Triassic biotic crisis. Paleogeography, Paleoclimatology, Paleoecology 627, 111723. https://doi.org/10.1016/j.paleo.2023.111723 External link.
• Xu, Y., Wang, Y., Li, L., Lu, N., Zhu, Y., Huang, Z. & McLoughlin, S. (2024). Plant-insect interactions across the Triassic–Jurassic boundary in the Sichuan Basin, South China. Frontiers in Ecology and Evolution 11, 1338865. https://doi.org/10.3389/fevo.2023.1338865 External link.
• Zhan, H.-X., Sui, Q., Wu, H., Lu, W.-Y., Chen, J., McLoughlin, S., Zhuo Feng, Z., (2025). Tenellisporites capillaris sp. nov., a new dispersed lycopsid megaspore from the Middle Triassic Badong Formation, Hunan Province, China. Review of Palaeobotany and Palynology XX, 105384. https://doi.org/10.1016/j.revpalbo.2025.105384 External link.