English: Size comparison showing several of the big ornithopod dinosaurs. Several giant length estimates have been proposed for different taxa, with varying degrees of accuracy. This diagram uses more rigorous estimates to avoid inaccuracy. The seven shown taxa are:

• Shantungosaurus giganteus (red) A large Chinese taxon measuring 15 meters long and weighing 13 tonnes. Zhuchengosaurus maximus and Huaxiaosaurus aigahtens are now considered to be larger specimens of this species.^[1] References: Skeletal^[2] Restoring of Fossils^[1]
• Magnapaulia laticaudus (yellow) Long considered to be a giant species of Lambeosaurus, this Mexican hadrosaur was about 12.5 meters long (no more recent mass estimate to my knowledge).^[3] References: Skeletal^[3]
• Edmontosaurus annectens (brown) This common American and Canadian hadrosaurid was generally around 9 meters long and 3.2 tonnes in mass, although some specimens could be considerably larger (up to 13 meters). Anatosaurus is synonymous with this genus, and the giant Anatotitan copei with this species, the latter likely represents the fully mature ontogenetic stage of this species.^[1][4][5][6] References: Skeletal^[1] Skull^[6]
• Saurolophus angustirostris (blue) This large Mongolian species is related to the more famous (although smaller) North American S. osborni. S. angustirostris could reach lengths of 13 meters and weights of 11 tonnes, and yet rarely receives the same attention as some of the other taxa shown here, despite being known from a nearly complete skeleton and ontogenetic series.^[1][7] References: Skeletal^[8][1] Skull^[7]
• Hypsibema missouriensis (orange) This poorly known dinosaur with taxonomic issues was nevertheless chosen to be Missouri's state fossil. It was approximately 10 meters long.^[9] References: Skeletal^[10]
• Charonosaurus jiayinensis (violet) Another Chinese species, Charonosaurus was similar to the famous Parasaurolophus. Charonosaurus was the larger of the two, growing up to 10 meters and 5 tonnes.^[1] References: Skeletal^[11]
• Iguanodon bernissartensis (green) The only Brittish taxon here, and the only non-hadrosaurid, Iguanodon was, on average, 8 meters long and 3.2 tonnes in mass. However, it did get bigger than this.^[1][5] References: Skeletal^[12]

1. ↑ ^{a b c d e f g h} Paul, Gregory S. The Princeton Field Guide to Dinosaurs. 2nd ed. Princeton, NJ: Princeton UP, 2016. Print.
2. ↑ GetAwayTrike (2017-2018). Super Edmontosaur
3. ↑ ^{a b} Prieto-Márquez A, Chiappe LM, Joshi SH (2012) The Lambeosaurine Dinosaur Magnapaulia laticaudus from the Late Cretaceous of Baja California, Northwestern Mexico. PLoS ONE 7(6): e38207. https://doi.org/10.1371/journal.pone.0038207
4. ↑ Horner JR, Goodwin MB, Myhrvold N (2011) Dinosaur Census Reveals Abundant Tyrannosaurus and Rare Ontogenetic Stages in the Upper Cretaceous Hell Creek Formation (Maastrichtian), Montana, USA. PLoS ONE 6(2): e16574. https://doi.org/10.1371/journal.pone.0016574
5. ↑ ^{a b} Palmer, Douglas, Simon Lamb, Angeles Gavira Guerrero, Peter Frances, and Jamie Ambrose. Prehistoric Life: The Definitive Visual History of Life on Earth. DK Publishing, 2012.
6. ↑ ^{a b} Campione NE, Evans DC (2011) Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America. PLoS ONE 6(9): e25186. https://doi.org/10.1371/journal.pone.0025186
7. ↑ ^{a b} Bell, Phil R. (2011). "Cranial Osteology and Ontogeny of Saurolophus angustirostris from the Late Cretaceous of Mongolia with Comments on Saurolophus osbornifrom Canada". Acta Palaeontologica Polonica 56 (4): 703–722. https://doi.org/10.4202/app.2010.0061.
8. ↑ GetAwayTrike (2019) Tarbosaurus killer
9. ↑ Powers, Marc (February 19, 2004). "A bone to pick for Missouri". Southeast Missourian. Southeast Missourian. Archived from the original on February 4, 2011. Retrieved on January 12, 2011.
10. ↑ Hartman, Scott (2011). "Gryposaurus monumentensis". Skeletal Drawing.
11. ↑ Godefroit, Pascal; Zan, Shuqin; Jin, Liyong (200) Charonosaurus jiayinensis ng, n. sp., a lambeosaurine dinosaur from the Late Maastrichtian of northeastern China. Comptes Rendus de l'Académie des Sciences-Series IIA-Earth and Planetary Science 330(12): 875-882.
12. ↑ Hartman, Scott (2016). "Iguanodon bernissartensis". Skeletal Drawing.