Uetz, P. et al. The Reptile Database (accessed 29 January 2024); http://www.reptile-database.org.
Evans, S. E. & Borsuk-Białynicka, M. A small lepidosauromorph reptile from the Early Triassic of Poland. Palaeontol. Pol. 65, 179–202 (2009).
Jones, M. E. H. et al. Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara). BMC Evol. Biol. 13, 208 (2013).
Sobral, G., Simões, T. R. & Schoch, R. R. A tiny new Middle Triassic stem-lepidosauromorph from Germany: implications for the early evolution of lepidosauromorphs and the Vellberg fauna. Sci. Rep. 10, 2273 (2020).
Tałanda, M., Fernandez, V., Panciroli, E., Evans, S. E. & Benson, R. J. Synchrotron tomography of a stem lizard elucidates early squamate anatomy. Nature 611, 99–104 (2022).
Evans, S. E. in Biology of the Reptilia Vol. 20 (eds Gans C. et al.) 1–347 (Society for the Study of Amphibians and Reptiles, 2008).
Evans, S. E. The skull of a new eosuchian reptile from the Lower Jurassic of South Wales. Zool. J. Linn. Soc. 70, 203–264 (1980).
Whiteside, D. The head skeleton of the Rhaetian sphenodontid Diphydontosaurus avonis gen. et sp. nov. and the modernizing of a living fossil. Phil. Trans. R. Soc. B 312, 379–430 (1986).
Nicholson, D. B., Holroyd, P. A., Benson, R. B. J. & Barrett, P. M. Climate-mediated diversification of turtles in the Cretaceous. Nat. Commun. 6, 7848 (2015).
Cleary, T. J., Benson, R. B. J., Evans, S. E. & Barrett, P. M. Lepidosaurian diversity in the Mesozoic–Palaeogene: the potential roles of sampling biases and environmental drivers. R. Soc. Open Sci. 5, 171830 (2018).
Ford, D. P., Evans, S. E., Choiniere, J. N., Fernandez, V. & Benson, R. B. J. A reassessment of the enigmatic diapsid Paliguana whitei and the early history of Lepidosauromorpha. Proc. R. Soc. B 288, 43 (2021).
Sues, H. D. & Schoch, R. R. The oldest known rhynchocephalian reptile from the Middle Triassic (Ladinian) of Germany and its phylogenetic position among Lepidosauromorpha. Anat. Rec. 307, 776–790 (2024).
Whiteside, D. I., Chambi-Trowell, S. A. V. & Benton, M. J. A Triassic crown squamate. Sci. Adv. 8, eabq8274 (2022).
Whiteside, D. I., Chambi-Trowell, S. A. V. & Benton, M. J. Late Triassic †Cryptovaranoides microlanius is a squamate, not an archosauromorph. R. Soc. Open Sci. 11, 231874 (2024).
Coram, R. A., Radley, J. D. & Benton, M. J. The Middle Triassic (Anisian) Otter Sandstone biota (Devon, UK): review, recent discoveries and ways ahead. Proc. Geol. Ass. 130, 294–306 (2019).
Jones, M. E. H. Skull shape and feeding strategy in Sphenodon and other Rhynchocephalia (Diapsida: Lepidosauria). J. Morphol. 269, 945–966 (2008).
De Queiroz, K., Cantino, P. & Gauthier, J. 2020. Phylonyms: A Companion to the PhyloCode (CRC Press, 2020).
Romer, A. S. Osteology of the Reptiles (Univ. Chicago Press, 1956).
De Mar, D. G. Jr, Jones, M. E. H. & Carrano, M. T. A nearly complete skeleton of a new eusphenodontian from the Upper Jurassic Morrison Formation, Wyoming, USA, provides insight into the evolution and diversity of Rhynchocephalia (Reptilia: Lepidosauria). J. Syst. Palaeontol. 20, 1–64 (2022).
Fraser, N. C. A new rhynchocephalian from the British Upper Triassic. Palaeontology 25, 709–725 (1982).
Chambi-Trowell, S. A. V., Whiteside, D. I. & Benton, M. J. Diversity in rhynchocephalian Clevosaurus skulls based on CT reconstruction of two Late Triassic species from Great Britain. Acta Palaeontol. Pol. 64, 41–64 (2019).
Robinson, P. L. A problematic reptile from the British Upper Trias. J. Geol. Soc. 129, 457–479 (1973).
Evans, S. E. & Jones, M. E. H. in New Aspects of Mesozoic Biodiversity (ed. Bandyopahyay, S.) 27–44 (Springer, 2010).
Fraser, N. C. The osteology and relationships of Clevosaurus (Reptilia: Sphenodontida). Phil. Trans. R. Soc. B 321, 125–178 (1988).
Apesteguia, S. & Novas, F. E. Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana. Nature 425, 609–612 (2003).
Chambi-Trowell, S. A. V., Whiteside, D. I., Benton, M. J. & Rayfield, E. J. Biomechanical properties of the jaws of two species of Clevosaurus and a reanalysis of rhynchocephalian dentary morphospace. Palaeontology 63, 919–939 (2020).
Jones, M. E. H., Curtis, N., O’Higgins, P., Fagan, M. & Evans, S. E. The head and neck muscles associated with feeding in Sphenodon (Reptilia: Lepidosauria: Rhynchocephalia). Palaeontol. Electron. 12, 12.2.7A (2009).
Whiteside, D. I., Duffin, C. J. & Furrer, H. The Late Triassic lepidosaur fauna from Hallau, North-Eastern and a new “basal” rhynchocephalian Deltadectes elvetica gen et. sp. nov. Neues Jahrb Geol. Paläontol. 285, 53–74 (2017).
Chambi-Trowell, S. A. V. et al. The diversity of Triassic South American sphenodontians: a new basal form, clevosaurs, and a revision of rhynchocephalian phylogeny. J. Syst. Palaeontol. 19, 787–820 (2021).
Hsiou, A. S. et al. A new clevosaurid from the Triassic (Carnian) of Brazil and the rise of sphenodontians in Gondwana. Sci. Rep. 9, 11821 (2019).
Simões, T. R. et al. The origin of squamates revealed by a Middle Triassic lizard from the Italian Alps. Nature 557, 706–709 (2018).
Martínez, R. N., Simões, T. R., Sobral, G. & Apesteguia, S. A. Triassic stem lepidosaur illuminates the origin of lizard-like reptiles. Nature 597, 235–238 (2021).
Griffiths, E. F., Ford, D. P., Benson, R. B. J. & Evans, S. E. New information on the Jurassic lepidosauromorph Marmoretta oxoniensis. Pap. Palaeontol. 7, 2255–2278 (2021).
Schoch, R. R. & Sues, H. D. A new lepidosauromorph reptile from the Middle Triassic (Ladinian) of Germany and its phylogenetic relationships. J. Vertebr. Paleontol. 38, e1444619 (2018).
Freisem, L. S., Müller, J., Suesd, H.-D. & Sobral, G. A new sphenodontian (Diapsida: Lepidosauria) from the Upper Triassic (Norian) of Germany and its implications for the mode of sphenodontian evolution. BMC Ecol. Evol. 24, 35 (2024).
Benton, M. J. & Donoghu, P. C. J. Paleontological evidence to date the tree of life. Mol. Biol. Evol. 24, 26–53 (2007).
Benton, M. J. Constraints on the timescale of animal evolutionary history. Palaeontol. Electron. 18.1.1FC, 1–106 (2015).
Ksepka, D. T. et al. The fossil calibration database—a new resource for divergence dating. Syst. Biol. 64, 853–859 (2015).
Simões, T. R. & Pyron, R. A. The squamate tree of life. Bull. Mus. Comp. Zool. 163, 47–95 (2021).
Simões, T. R., Kammerer, C. F., Caldwell, M. W. & Pierce, S. E. Successive climate crises in the deep past drove the early evolution and radiation of reptiles. Sci. Adv. 8, eabq1898 (2022).
Benton, M. J. & Wu, F. Triassic revolution. Front. Earth Sci. 10, 899541 (2022).
O’Brien, A., Whiteside, D. I. & Marshall, J. E. A. Anatomical study of two previously undescribed specimens of Clevosaurus hudsoni (Lepidosauria: Rhynchocephalia) from Cromhall Quarry, UK, aided by computed tomography, yields additional information on the skeleton and hitherto undescribed bones. Zool. J. Linn. Soc. 183, 163–195 (2018).
Jones, M. E. H., Curtis, N., O’Higgins, P., Fagan, M. J. & Evans, S. E. Hard tissue anatomy of the cranial joints in Sphenodon (Rhynchocephalia): sutures, kinesis and skull mechanics. Palaeontol. Electron. 14, 17A (2011).
Mahler, D. L. & Kearney, M. The palatal dentition in squamate reptiles: morphology, development, attachment, and replacement. Fieldiana Zool. 108, 1–61 (2006).
Matsumoto, R. & Evans, S. E. The palatal dentition of tetrapods and its functional significance. J. Anat. 230, 47–65 (2017).
Clapham, M. E. & Karr, J. A. Environmental and biotic controls on the evolutionary history of insect body size. Proc. Natl Acad. Sci. USA 109, 10927–10930 (2012).
Ambrose, K., Hough, E., Smith, N. J., Warrington, G. Lithostratigraphy of the Sherwood Sandstone Group of England, Wales and south-west Scotland. Report RR/14/01 (British Geological Survey Research, 2014).
Hounslow, M. W. & McIntosh, G. Magnetostratigraphy of the Sherwood Sandstone Group (Lower and Middle Triassic), south Devon, UK: detailed correlation of the marine and non-marine Anisian. Palaeogeogr. Palaeoclimatol. Palaeoecol. 193, 325–348 (2003).
Coram, R. A., Radley, J. D. & Benton, M. J. Triassic tragedy—a bone bed in the Otter Sandstone of East Devon, south‐west England. Geol. Today 37, 176–183 (2021).
Gallois, R. The stratigraphy of the Permo-Triassic rocks of the Dorset and East Devon Coast World Heritage Site, UK. Proc. Geol. Ass. 130, 274–293 (2019).
Zaher, M., Coram, R. A. & Benton, M. J. The Middle Triassic procolophonid Kapes bentoni: computed tomography of the skull and skeleton. Pap. Palaeontol. 5, 111–138 (2019).
Cavicchini, I., Zaher, M. & Benton, M. J. An enigmatic neodiapsid reptile from the Middle Triassic of England. J. Vertebr. Paleontol. 40, e1781143 (2020).
Avizo v.2020.2. (Thermo Fisher Scientific, 2020).
Blender v.2.93.3 (Stichting Blender Foundation, 2018).
Paganin, D., Mayo, S., Gureyev, T. E., Miller, P. R. & Wilkins, S. W. Simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object. J. Microsc. 206, 33–40 (2002).
Paganin, D. M. et al. Boosting spatial resolution by incorporating periodic boundary conditions into single-distance hard-X-ray phase retrieval. J. Optics 22, 115607 (2020).
Paleo, P., Mirone, A., Nemoz, C. and Viganò, N. R. Nabu. GitLab https://gitlab.esrf.fr/tomotools/nabu (2019).
Lyckegaard, A., Johnson, G. & Tafforeau, P. Correction of ring artifacts in X-ray tomographic images. Int. J. Tomo. Stat. 18, 1–9 (2011).
Drakopoulos, M. T. et al. I12: the Joint Engineering, Environment and Processing (JEEP) beamline at Diamond Light Source. J. Synchrotron Radiat. 22, 828–838 (2015).
Vo, N. T., Atwood, R. C., Drakopoulos, M. & Connolley, T. Data processing methods and data acquisition for samples larger than the field of view in parallel-beam tomography. Opt. Express 29, 17849–17874 (2021).
Kazanstev, D., Wadeson, N. & Basham, M. High performance Savu software for fast 3D model-based iterative reconstruction of large data at Diamond Light Source. SoftwareX 19, 101157 (2021).
Aarle, W. et al. Fast and flexible X-ray tomography using the ASTRA toolbox. Opt. Express 24, 25129–25147 (2016).
Dragonfly v.2022.2 (Comet Technologies Canada Inc., 2022).
Carroll, R. L. & Lindsay, W. Cranial anatomy of the primitive reptile. Procolophon. Can. J. Earth Sci. 22, 1571–1587 (1985).
Debraga, M. The postcranial skeleton, phylogenetic position, and probable lifestyle of the Early Triassic reptile Procolophon trigoniceps. Can. J. Earth Sci. 40, 527–556 (2003).
Jenkins, K. M., Bell, C. J., Hancox, P. J. & Lewis, P. J. A new species of Palacrodon and a unique form of tooth attachment in reptiles. J. Vertebr. Paleontol. 43, e2328658 (2023).
Gauthier, J. A., Kearney, M., Maisano, J. A., Rieppel, O. & Behlke, A. D. B. Assembling the squamate tree of life: perspectives from the phenotype and the fossil record. Bull. Peabody Mus. Nat. Hist. 53, 3–308 (2012).
Burbrink, F. T. et al. Interrogating genomic-scale data for Squamata (lizards, snakes, and amphisbaenians) shows no support for key traditional morphological relationships. Syst. Biol. 69, 502–520 (2020).
Singhal, S. et al. Congruence and conflict in the higher-level phylogenetics of squamate reptiles: an expanded phylogenomic perspective. Syst. Biol. 70, 542–557 (2021).
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).
The R Development Core Team. R: A Language and Environment for Statistical Computing v.3.6.9 (R Foundation for Statistical Computing, 2021).
Paradis, E., Claude, J. & Strimmer, K. APE: analyses of phylogenetics and evolution in R language. Bioinformatics 20, 289–290 (2004).
Swofford, D. L. PAUP* Phylogenetic Analysis Using Parsimony (*and Other Methods) version 4. PhyloSolutions http://paup.csit.fsu.edu/ (2003).
Ronquist, F. et al. MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space. Syst. Biol. 61, 539–542 (2012).
Bapst, D. W. paleotree: Paleontological and phylogenetic analyses of evolution. Methods Ecol. Evol. 3, 803–807 (2012).
Bell, M. A. & Lloyd, G. T. strap: an R package for plotting phylogenies against stratigraphy and assessing their stratigraphic congruence. Palaeontology 58, 379–389 (2015).
Benton, M. & Fernandez, V. Synchrotron X-ray CT raw data for the characterization of the skull of Agriodontosaurus helsbypetrae BRSUG 29950-14 (Version 1) [Dataset]. European Synchrotron Radiation Facility https://doi.org/10.15151/ESRF-DC-2158672188 (2025).
Benton, M. J. & Fernandez, V. Synchrotron X-ray CT processed data of the skull of Agriodontosaurus helsbypetrae BRSUG 29950-14 (Version 1) [Dataset]. European Synchrotron Radiation Facility https://doi.org/10.15151/ESRF-DC-2160804068 (2025).
