DOI: 10.5061/dryad.v6wwpzh78
title: Data from: The origins of neural spine elongation in iguanodontian dinosaurs and the osteology of a new sail-back styracosternan (Dinosauria: Ornithischia) from the Lower Cretaceous Wealden Group of England

description: The Wealden Group of southern England was deposited during the late
 Berriasian into the early Aptian. It records a critical time in the
 development of iguanodontian dinosaur diversity, from the low levels of
 the Jurassic to the higher levels in the Aptian and Albian. A new
 iguanodontian dinosaur, Istiorachis macarthurae gen. et sp. nov. from the
 Wessex Formation (Wealden Group) of the Isle of Wight, exhibits
 hyperelongation of the dorsal and caudal neural spines, suggesting that it
 possessed a possible sail structure. Ancestral state reconstruction for
 the relative height of dorsal neural spines in iguanodontians reveals that
 modest elongation began with Ankylopollexia in the Late Cretaceous and
 elongation became established during the Cenomanian stage of the Late
 Cretaceous, albeit with widely disparate values. Hyperelongation of neural
 spines occurred sporadically throughout the Cretaceous, being most
 frequently recorded in the Barremian and early Aptian. Possible
 explanations for neural spine elongation in Ankylopollexia include
 biomechanical advantage, perhaps related to greater mass and a locomotory
 shift towards quadrupedalism, and visual signalling either driven by
 sexual selection or species recognition. The function of elongate neural
 spines was probably pluralistic and differed in different taxa. No single
 explanation fully supports the variation seen throughout the Cretaceous.
description: # Data from: The origins of neural spine elongation in iguanodontian
 dinosaurs and the osteology of a new sail-back styracosternan (Dinosauria:
 Ornithischia) from the Lower Cretaceous Wealden Group of England Dataset
 DOI: [10.5061/dryad.v6wwpzh78](10.5061/dryad.v6wwpzh78) ## Description of
 the data and file structure GENERAL INFORMATION Data set for: The origins
 of neural spine elongation in iguanodontian dinosaurs and the osteology of
 a new sail-back styracosternan (Dinosauria: Ornithischia) from the Lower
 Cretaceous Wealden Group of England. Jeremy A. F. Lockwood
 [http://orchid](http://orchid) .org/000-0002-3233-0819 Fossil Reptiles,
 Amphibians and Birds Section, Natural History Museum, London SW7 5BD, UK.
 [jlockwood156@aol.com](mailto:jlockwood156@aol.com) Susannah C. R.
 Maidment [http://orchid](http://orchid) .org/000-0002-7741-2500 Fossil
 Reptiles, Amphibians and Birds Section, Natural History Museum, London SW7
 5BD, UK. [susannah.maidment@nhm.ac.uk](mailto:susannah.maidment@nhm.ac.uk)
 David M. Martill [http://orchid](http://orchid) .org/000-0002-3208-5702
 School of the Environment and Life Sciences, University of Portsmouth PO1
 2DT, UK. [david.martill@port.ac.uk](mailto:david.martill@port.ac.uk) ####
 **INTRODUCTION** Relative neural spine height in the posterior dorsal
 vertebrae of ornithopod dinosaurs was investigated by performing Log10
 transformed bivariate plots of estimated body mass versus 1. the anterior
 dorsoventral height of the anterior articular surface of the centrum (Ch)
 and 2. the ratio of the neural spine height to the anterior centrum height
 (Nh/Ch ratio). Ancestral state reconstruction for neural spine elongation
 was performed using the most parsimonious tree recovered from an extended
 implied weights analysis (k=3) of iguanodontian dinosaurs . First, the
 tree was time-calibrated using the TimePaleoPhy function in the R package
 Paleotree (Bapst 2012), with minimum branch lengths of 0.5 million years.
 Taxa without neural spine data were then pruned. Ancestral states of
 posterior dorsal vertebrae neural spine heights, expressed as ratios to
 anterior centrum height (Nh/Ch ratio) were calculated using the anc.ML
 function in the R package Phytools (Revell 2024), which uses a Brownian
 motion model of evolution and maximum likelihood. All analyses were
 carried out in R v4.0.4 (R Core Team 2021). ### Files and variables ####
 **File 1.** Neural_Spine_Full_Data.xlsx Type of file: Microsoft Excel
 Worksheet (.xlsx) Description. Spead sheet containing three separate
 sheets. A. 50 ornithopod taxa. Variables: Neural spine dorsoventral
 height, neural spine anteroposterior width, dorsoventral height of
 anterior articular surface of centrum, mass estimate, age range, specimen
 numbers and references for 50 taxa used in bivariate regressions.
 Abbreviations used: Ch, dorsoventral height of centrum; Nh, neural spine
 dorsoventral height; Nw, maximum anteroposterior width of dorsal half of
 the neural spine; Mass (kg), total body mass; Position, estimated position
 of the vertebra in the dorsal column; Stage, stratigraphic position of
 taxon; Time span, based on the International Chronostratigraphic Chart
 2023; Clade names follow Poole, K. E. 2022. Phylogeny of iguanodontian
 dinosaurs and the evolution of quadrupedality. Palaeontologica
 Electronica, 25.3.a30, 1–65. B. Mass Data: Body mass estimates for 50 taxa
 used in bivariate regressions. FL = Femoral length. Body mass A represents
 specimens where the femoral length was known with mass calculated using
 the regression equation for ornithischians in O'Gorman & Hone
 2012, y = 3,0567x - 2.7042, where y = log10 body mass (g) and x = log10
 femoral length (mm). Estimates in Body Mass B are less precise. C.
 Ancestral Data: Taxa, mean age and neural spine height to centrum height
 ratios for use in ancestral states reconstruction. Files 2-5 contain final
 data for ancestral states reconstruction. #### **File 2.**
 Neural_spine_data_for_ancestral_states.csv  Type of file: Microsoft Excel
 Comma Separated Values File (.cvs). Description. Spreadsheet containing
 neural spine to centrum (Nh/Ch) ratios for taxa used in the ancestral
 states reconstruction after pruning. #### **File 3.**
 Age_data_for_Neural_spines_ancestral_states.txt Age data for neural spine
 ancestral states reconstruction. Type of file: Text document (.txt). ####
 **File 4. **R_code_for_Neural_spines_ancestral_states_Dryad.R R Code for
 neural spine ancestral states reconstruction. Type of file: R File (.R). R
 code and instructions used in ancestral states reconstruction. #### **File
 5. Tree_for_Neural_spines_ancestral_states.nex** Tree for neural spine
 ancestral states reconstruction. Type of file: NEX File (.nex).
 **References:** Bapst, D. W. 2012. Paleotree: an R package for
 paleontological and phylogenetic analyses of evolution. Methods in Ecology
 & Evolution, 3, 803–807. R Core Team 2021. R: a language and
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 Statistical Computing.
 [https://www.R-project.org](https://www.R-project.org) Revell, L. J. 2024.
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 (and other things). other things). PeerJ, 12 e16505, 1–75.
 [https://doi.org/10.7717/peerj.16505](https://doi.org/10.7717/peerj.16505). Date of Data Collection: 2023 ### **SHARING/ACCESS INFORMATION** Data for neural spine height, width and the dorsoventral height of the anterior articular surface of the centrum was obtained by personal examination (JAFL) and the following sources (followed by taxon and accession number): Baron, M. G., Norman, D, B. & Barrett, P. M. 2016. Postcranial anatomy of *Lesothosaurus diagnosticus* (Dinosauria: Ornithischia) from the Lower Jurassic of southern Africa: implications for basal ornithischian taxonomy and systematics. Zoological Journal of the Linnean Society, 179, 125–168. ***LESOTHOSAURUS DIAGNOSTICUS*** (SAM-PK-K1107 referred) Bartholomai, A. & Molnar, R. E. 1981. *Muttaburrasaurus*, a new iguanodontid (Ornithischia: Ornithopoda) dinosaur from the Lower Cretaceous of Queensland. Memoirs of the Queensland Museum, 20, 319–49. ***MUTTABURRASAURUS LANGDONI*** (QM F6140 Type) Bertozzo, F., Della Vecchia, F. 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Bernissart dinosaurs and Early Cretaceous Terrestrial ecosystems, Indiana University Press, Bloomington, USA. ***BOLONG YIXIANENSIS*** (YHZ-001 Type) Xing, H., Wang, D., Han, F., Sullivan, C., Ma, Q., He, Y., Hone, D. W. E., Yan, R., Du, F. and Xu, X. 2014. A new basal hadrosauroid dinosaur (Dinosauria: Ornithopoda) with transitional features from the Late Cretaceous of Henan Province, China. PLoS ONE, 9, e98821. doi: 10.1371/journal.pone.0098821. ***ZHANGHENGLONG YANGCHENGENSIS*** (XMDFEC V0014 paratype) Xu, X., Zhao, X., Lu, J., Huang, W., Li, Z. and Dong, Z. 2000. A new iguanodontian from Sangping Formation of Neixiang, Henan and its stratigraphical implication. Vertebrata Palasiatica, 7, 176–191. ***NANYANGOSAURUS ZHUGEII*** (IVPP V.11821 Type) You, H., Ji, Q. and Li, D. 2005. *Lanzhousaurus magnidens* gen. et sp. nov. from Gansu Province, China: the largest-toothed herbivorous dinosaur in the world. Geological Bulletin of China, 24, 785–794. ***LANZHOUSAURUS MAGNIDENS*** (GSLTZP 1- 1 Type) Personal examination (JAFL). ***BARILIUM DAWSONI*** (NHMUK PV R 798A Type), ***BRIGHSTONEUS SIMMONDSI*** (MIWG 6344 Type), ***COMPTONATUS CHASEI*** (IWCMS 2014.80 Type), ***HYPSELOSPINUS FITTONI*** (NHMUK PV R 604 referred), ***ISTIORACHIS MACARTHURAE*** (MIWG 6344 Type). Body mass estimates were calculated where possible from femoral length using the equation y = 3,0567x - 2.7042, where y = log10 body mass (g) and x = log10 femoral length (mm). Reference: O'Gorman, E. J. & Hone, D. W. J. 2012. Body Size Distribution of the Dinosaurs. PLoS ONE 7(12): e51925. doi:10.1371/journal.pone. Data on femoral lengths were obtained from the following sources which are cited on the spreadsheet. Benson, R. B. J., Campione, N.E., Carrano, M. T, Mannion, P. D., Sullivan, C. et al. 2014. Rates of dinosaur body mass evolution indicate 170 Million Years of sustained ecological innovation on the avian stem lineage. PLoS Biol 12(5): e1001853. doi:10.1371/journal.pbio.1001853. Lockwood, J. A. F., Martill, D. M. & Maidment, S. R. M. 2021. A new hadrosauriform dinosaur from the Wessex Formation of the Isle of Wight, southern England, Journal of Systematic Palaeontology, 19, 847–888. Lockwood, J. A. F., Martill, D. M. & Maidment, S. R. M. 2024. *Comptonatus chasei*, a new iguanodontian dinosaur from the Lower Cretaceous Wessex Formation, Wealden Group (Early Cretaceous), of the Isle of Wight, southern England. Journal of Systematic Palaeontology, 22 (1), 2346573. McDonald, A. T., Bird, J., Kirkland, J. I. & Dodson, P. 2012a. Osteology of the basal hadrosauroid *Eolambia caroljonesa* (Dinosauria: Ornithopoda) from the Cedar Mountain Formation of Utah. PLoS ONE 7, e45712. doi: 10.1371/journal.pone.0045712. Norman, D. B. 1986. On the anatomy of *Iguanodon atherfieldensis* (Ornithischia: Ornithopoda). Bulletin de L'institut Royal des Sciences Naturelles de Belgique Sciences de la Terre, 56, 281–372. Prieto-Márquez, A. 2001. Osteology and variation of *Brachylophosaurus canadensis* (Dinosauria, Hadrosauridae) from the Upper Cretaceous Judith River Formation of Montana. Master’s thesis, Montana State University, Bozeman, USA. 390 pp. Ramírez-Velasco, A. A., Benammi, M., Prieto-Márquez, A., Ortega, J. A. & Hernández-Rivera, R. 2012. *Huehuecanauhtlus tiquichensis*, a new hadrosauroid dinosaur (Ornithischia: Ornithopoda) from the Santonian (Late Cretaceous) of Michoacán, Mexico. Canadian Journal of Earth Sciences, 49, 379–395. Tsogtbaatar, K., Weishampel, D. B., Evans, D. C.& Watabe, M. 2019. A new hadrosauroid (Dinosauria: Ornithopoda) from the Late Cretaceous Baynshire Formation of the Gobi Desert (Mongolia). PLoS ONE, 14, e0208480. doi: 10.1371/journal.pone.0208480. Verdú, F. J., Royo-Torres, R., Cobos, A. & Alcalá, L. 2018. New systematic and phylogenetic data about the early Barremian *Iguanodon galvensis* (Ornithopoda: Iguanodontoidea) from Spain. Historical Biology, 30, 437–474. Xing, H., Wang, D., Han, F., Sullivan, C., Ma, Q., He, Y., Hone, D. W. E., Yan, R., Du, F. & Xu, X. 2014. A new basal hadrosauroid dinosaur (Dinosauria: Ornithopoda) with transitional features from the Late Cretaceous of Henan Province, China. PLoS ONE, 9, e98821. doi: 10.1371/journal.pone.0098821. Mass estimates were also taken from Paul, G. S. 2016. The Princeton field guide to dinosaurs. 2nd edition. Princeton University Press, New Jersey, USA. 360 pp.