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
Data files
Aug 16, 2025 version files 57.74 KB
Abstract
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.
Dataset DOI: 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 .org/000-0002-3233-0819
Fossil Reptiles, Amphibians and Birds Section, Natural History Museum, London SW7 5BD, UK.
Susannah C. R. Maidment
http://orchid .org/000-0002-7741-2500
Fossil Reptiles, Amphibians and Birds Section, Natural History Museum, London SW7 5BD, UK.
David M. Martill
http://orchid .org/000-0002-3208-5702
School of the Environment and Life Sciences, University of Portsmouth PO1 2DT, 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 environment for statistical computing. Version 4.0.4. R Foundation for Statistical Computing. https://www.R-project.org
Revell, L. J. 2024. phytools 2.0: an updated R ecosystem for phylogenetic comparative methods (and other things). other things). PeerJ, 12 e16505, 1–75. 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. M. and Fabbri, M. 2017a. The Venice specimen of Ouranosaurus nigeriensis (Dinosauria, Ornithopoda). PeerJ. 5, 1–70. e3403; doi: 10.7717/peerj.3403. OURANOSAURUS NIGERIENSIS (MSNVE 3714 referred)
Borinder, N. H., Poropat, S. F., Campione, N. E., Wigren, T. and Kear, B. P. 2021. Postcranial osteology of the basally branching hadrosauroid dinosaur Tanius sinensis from the Upper Cretaceous Wangshi Group of Shandong, China, Journal of Vertebrate Paleontology, 41, doi: 10.1080/02724634.2021.1914642. TANIUS SINENSIS (PMU 24720/11 Type)
Brown, B. 1913. A new trachodont dinosaur, Hypacrosaurus, from the Edmonton Cretaceous of Alberta. Bulletin of the American Museum of Natural History, 32, 395–406. HYPACROSAURUS ALTISPINUS (AMNH 5206 paratype)
Butler, R. J., Smith, R. M. H. and Norman, D. B. 2007. A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia. Proceedings of the Royal Society B; Biological Sciences. 274 (1621) 2041–6. EOCURSOR PARVUS (SAM-PK-K8025 Type)
Carpenter, K. and Galton, P. M. 2018 A photo documentation of bipedal ornithischian dinosaurs from the Upper Jurassic Morrison Formation, USA. Geology of the Intermountain West, 5, 167–207. DRYOSAURUS ALTUS (YPM VP 1876 Type)
Carpenter, K. and Wilson, Y. 2008. A new species of Camptosaurus (Ornithopoda: Dinosauria) from the Morrison Formation (Upper Jurassic) of Dinosaur National Monument, Utah, and a biomechanical analysis of its forelimb. Annals of Carnegie Museum, 76, 227–263. UTEODON APHANOECETES (CM 11337 Type)
Chanthasit, P. 2010. The ornithopod dinosaur Rhabdodon from the Late Cretaceous of France: anatomy, systematics and paleobiology. Ph.D. thesis paléontology, Université Claude Bernard, Lyon, France, 196 pp. RHABDODON PRISCUS (CM-496 referred)
Dalla Vecchia, F. M. 2009. Tethyshadros insularis, a new hadrosauroid dinosaur (Ornithischia) from the Upper Cretaceous of Italy. Journal of Vertebrate Paleontology, 29, 1100–1116. TETHYSHADROS INSULARIS (SC 57021 Type)
Forster, C. A. 1990. The postcranial skeleton of the ornithopod dinosaur Tenontosaurus tilletti. Journal of Vertebrate Paleontology, 10, 273–294. TENONTOSAURUS TILLETTI (OMNH 10132 referred)
Galton, P. M. 1974. The ornithischian dinosaur Hypsilophodon from the Wealden of the Isle of Wight. Bulletin of the British Museum (Natural History), Geology, 25, 1–152. HYPSILOPHODON FOXII (NHMUK PV R 195 referred)
Gasulla, J. M., Escaso, F. Narvaez, I., Otega, F. and Sanz, J. L. 2015. A new sail-backed styrocasternan (Dinosauria: Ornithopoda) from the Early Cretaceous of Morella, Spain. PLoS ONE, 10, e0144167. doi: 10.1371/journal.pone.0144167. MORELLADON BELTRANI (CMP-MS-03 Type)
Gilmore, C. 1909. Osteology of the Jurassic reptile Camptosaurus, with a revision of the species of the genus, and descriptions of two new species. Proceedings of the United States National Museum, 36, 197–332. CAMPTOSAURUS DISPAR (USNM 4282 referred)
Gilmore, C. W. 1913. A new dinosaur from the Lance Formation of Wyoming. Smithsonian Miscellaneous Collections, 61, 1–5. THESCELOSAURUS NEGLECTUS (USNM 7757 Type)
Gilmore, C. W. 1933. On the dinosaurian fauna of the Iren Dabasu Formation. Bulletin of the American Museum of Natural History, 67, 23–78. BACTROSAURUS JOHNSONI (AMNH 6553 Type)
Godefroit P., Codrea V. & Weishampel D. B. 2009. Osteology of Zalmoxes shqiperorum (Dinosauria, Ornithopoda), based on new specimens from the Upper Cretaceous of Nalat-Vad (Romania). Geodiversitas, 31, 525–553. ZALMOXES SHQIPERORUM (UBB NVZ1-5 referred)
He, X.-L. and Cai, K.-J. 1983 A new species of Yandusaurus (hypsilophodont dinosaur) from the Middle Jurassic of Dashanpu, Zigong, Sichuan (in Chinese). Journal of Chengdu College of Geology (Supplement 1), 5–14. HEXINLUSAURUS MULTIDENS (T6001 Type)
Janensch, W. 1955. Der Ornithopode Dysalotosaurus der Tendaguruschichten. Palaeontographica (Supplementbände 7), 3, 105–176. DYSALOTOSAURUS LETTOWVORBECKI (dy III referred)
Lambe, L. M. 1920. The hadrosaur Edmontosaurus from the Upper Cretaceous of Alberta, Canada. Geological Survey Memoir, Canada Department of Mines, 120, 1–79. EDMONTOSAURUS REGALIS (NMC 2289 paratype)
Makovicky, P. J., Kilbourne. B. M., Sadleir, R. W. and Norell, M. A. 2011. A new basal ornithopod (Dinosauria, Ornithischia) from the Late Cretaceous of Mongolia. Journal of Vertebrate Paleontology. 31 (3): 626–640. HAYA GRIVA (IGM 100/2015 referred)
Maryańska, T. and Osmólska, H. 1981. First lambeosaurine dinosaur from Nemegt Formation, Upper Cretaceous, Mongolia. Acta Palaeontologica Polonica, 26, 243–255. BARSBOLDIA SICINSKII (ZPal MgD-I/110)
McDonald, A. T., Bird, J., Kirkland, J. I. and Dodson, P. 2012. 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. EOLAMBIA CAROLJONESA (CEUM 52173 (WS8) referred)
McDonald, A. T., Kirkland, J. I., DeBlieux, D. D., Madsen, S. K., Cavin, J., Milner, A. R. C. and Panzarin, l. 2010. New basal iguanodonts from the Cedar Mountain Formation of Utah and the evolution of thumb-spiked dinosaurs. PLoS ONE, 5, e14075. doi: 10.1371/journal.pone.0014075. HIPPODRACO SCUTODENS (UMNH VP 20208 Type)
McDonald, A. T., Kirkland, J. I., DeBlieux, D. D., Madsen, S. K., Cavin, J., Milner, A. R. C. and Panzarin, l. 2010. New basal iguanodonts from the Cedar Mountain Formation of Utah and the evolution of thumb-spiked dinosaurs. PLoS ONE, 5, e14075. doi: 10.1371/journal.pone.0014075. IGUANACOLOSSUS FORTIS (UMNH VP 20205 Type)
Norman, D. B. 1980. On the ornithischian dinosaur Iguanodon bernissartensis of Bernissart (Belgium). Mémoires de l'Institut Royal des Sciences Naturelles de Belgique, 178, 1–105. IGUANODON BERNISSARTENSIS (RBINS R342 referred)
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. RBINS R57 ‘DOLLODON BAMPINGI’ (RBINS R57)
Novas, F. E., Cambiaso, A. V. and Ambrosio, A. 2004. A new basal iguanodontian (Dinosauria, Ornithischia) from the Upper Cretaceous of Patagonia. Ameghiniana, 41 (1): 75-82. TALENKAUEN SANTACRUCENSIS (MPM 10001 Type)
Parks, W. A. 1922. Parasaurolophus walkeri, a new genus and species of trachodont dinosaur. University of Toronto Studies: Geological Series, 13, 5–32. PARASAUROLOPHUS WALKERI (ROM 768 Type)
Peng, G. 1990. A new small ornithopod (Agilisaurus louderbacki gen. et sp. nov.) from Zigong, China. Newsletter of the Zigong Dinosaur Museum, 2, 19–27. AGILISAURUS LOUDERBACKI (ZDM 6011 Type)
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. BRACHYLOPHOSAURUS CANADENSIS (MOR 1071 referred)
Prieto-Márquez, A. and Norell, M. A. 2010. Anatomy and relationships of Gilmoreosaurus mongoliensis (Dinosauria: Hadrosauroidea) from the Late Cretaceous of Central Asia. American Museum Novitiates, 3694, 1–52. GILMOREOSAURUS MONGOLIENSIS (AMNH FARB 30683 referred)
Ramírez-Velasco, A. A., Benammi, M., Prieto-Márquez, A., Ortega, J. A. and 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. HUEHUECANAUHTLUS TIQUICHENSIS ( IGM 6253 Type)
Scheetz, R. D., 1999, Osteology of Orodromeus makelai and the phylogeny of basal ornithopod dinosaurs Ph.D. thesis in biology, Montana State University, Bozeman, USA. 189 pp. ORODROMEUS MAKELAI (MOR 473 referred)
Sues, H., Evans, D. C., Galton, P. M. and Brown, C. M. 2023. Anatomy of the neornithischian dinosaur Parksosaurus warreni (Parks, 1926) from the Upper Cretaceous (lower Maastrichtian) Horseshoe Canyon Formation of Alberta, Canada. Cretaceous Research, 141, 105369. PARKSOSAURUS WARRENI (ROM 804 Type)
Taquet, P. and Russell, D. A. 1999. A massively constructed iguanodont from Gadoufaoua, Lower Cretaceous of Niger. Annales de paléontologie, 85(1), 85–96. LURDUSAURUS ARENATUS (MNHN GDF 1700 Type)
Tsogtbaatar, K., Weishampel, D. B., Evans, D. C.and 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. GOBIHADROS MONGOLIENSIS (MPC-D100/746)
Verdú, F. J., Royo-Torres, R., Cobos, A. and Alcalá, L. 2021. Systematics and paleobiology of a new articulated axial specimen referred to Iguanodon cf. galvensis (Ornithopoda, Iguanodontoidea), Journal of Vertebrate Paleontology, doi: 10.1080/02724634.2021.1878202. IGUANODON GALVENSIS (MAP 2063 referred)
Wang, X., Pan, R., Butler, R. J. and Barrett, P. M. 2010. The postcranial skeleton of the iguanodontian ornithopod Jinzhousaurus yangi from the Lower Cretaceous Yixian Formation of western Liaoning, China. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 101, 1–25. JINZHOUSAURUS YANGI (IVPP V12691 Type)
Weishampel, D. B., Jianu, C-M., Csiki, Z. and Norman, D. B. 2003. Osteology and phylogeny of Zalmoxes (n. g.), an unusual euornithopod dinosaur from the latest Cretaceous of Romania. Journal of Systematic Palaeontology, 1, 65–123. ZALMOXES ROBUSTUS (NHMUK PV R 4972 referred)
Winkler, D. A., Murry, P. A. and Jacobs, L. L. 1997. A new species of Tenontosaurus (Dinosauria: Ornithopoda) from the Early Cretaceous of Texas. Journal of Vertebrate Paleontology, 17, 330–348. TENONTOSAURUS DOSSI (FWMSH 93B1 Type)
Wu, W. and Godefroit P. 2012. Anatomy and relationships of Bolong yixianensis, an Early Cretaceous iguanodontoid dinosaur from Western Liaoning, China. Pp. 292–333 in P. Godefroit (ed.) 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.