Alternative spellings: Hydrosauridae, Madrosauridae
Invalid subtaxa: Arstanosaurus Shilin and Suslov 1982 [nomen dubium], Arstanosaurus akkurganensis Shilin and Suslov 1982 [nomen dubium], Cionodon Cope 1874 [nomen dubium], Cionodon arctatus Cope 1874 [nomen dubium], Claorhynchus Cope 1892 [nomen dubium], Claosauridae Marsh 1890, Craspedodon hillii Newton 1892 [nomen dubium], Diclonius Cope 1876 [nomen dubium], Edmontosaurus minor Cope 1869 [nomen dubium], Hadrosaurus breviceps Marsh 1889 [nomen dubium], Hadrosaurus cavatus Cope 1871 [nomen dubium], Hadrosaurus minor Cope 1869 [nomen dubium], Hypsibema Cope 1869 [nomen dubium], Hypsibema missouriense Gilmore and Stewart 1945 [nomen dubium], Hypsibema missouriensis Gilmore and Stewart 1945 [nomen dubium], Iguanodon hilli Newton 1892 [nomen dubium], Iguanodon hillii Newton 1892 [nomen dubium], Kritosaurus breviceps Marsh 1889 [nomen dubium], Limnosaurus hilli Newton 1892 [nomen dubium], Microhadrosaurus Dong 1979 [nomen dubium], Neosaurus missouriensis Gilmore and Stewart 1945 [nomen dubium], Orthomerus Seeley 1883 [nomen dubium], Orthomerus hilli Newton 1892 [nomen dubium], Orthomerus hillii Newton 1892 [nomen dubium], Parrosaurus Gilmore 1945 [nomen dubium], Parrosaurus missouriensis Gilmore and Stewart 1945 [nomen dubium], Prohadrosauridae Huene 1956, Pteropelyx Cope 1889 [nomen dubium], Pterypelyx Cope 1889 [nomen dubium], Saurolophus krischtofovici Riabinin 1930 [nomen dubium], Saurolophus kryschtofovici Riabinin 1930 [nomen dubium], Saurolophus krystofovici Riabinin 1930 [nomen dubium], Saurornithoides isfarensis Nessov 1995 [nomen dubium], Thespesius Leidy 1856 [nomen dubium], Trachodon Leidy 1856 [nomen dubium], Trachodon (Pteropelyx) Cope 1889 [nomen dubium], Trachodon breviceps Marsh 1889 [nomen dubium], Trachodon cavatus Cope 1871 [nomen dubium], Trachodon minor Cope 1869 [nomen dubium], Trachodontidae Lydekker 1888, Trachydontidae Lydekker 1888, Trachyodontidae Lydekker 1888, Troodon isfarensis Nessov 1995 [nomen dubium], Tyrannosauropus Haubold 1971 [nomen dubium]
Full reference: E. D. Cope. 1870. Synopsis of the extinct Batrachia, Reptilia and Aves of North America. Transactions of the American Philosophical Society, New Series 14(1):1-252
Parent taxon: Hadrosauroidea according to A. A. Ramírez-Velasco et al. 2012
Sister taxa: Bactrosaurus, Batyrosaurus, Bolong, Cedrorestes, Claosaurus, Eolambia, Equijubus, Fukuisaurus, Gilmoreosaurus, Glishades, Huehuecanauhtlus, Jeyawati, Jintasaurus, Jinzhousaurus, Levnesovia, Mantellisaurus, Nanyangosaurus, Penelopognathus, Probactrosaurus, Protohadros, Saurolophidae, Shuangmiaosaurus, Spheroolithidae, Tanius, Telmatosaurus, Tethyshadros, Xuwulong
Subtaxa: Edmontosaurinae, Euhadrosauria, Gryposaurinae, Hadrosaurinae, Hadrosauropodus, Hadrosaurus, Lambeosaurinae, Lapampasaurus, Maiasaurinae, Prohadrosaurinae, Protrachodontinae, Saurolophinae, Sphenospondylus, Taponichnus, Telosichnus, Trachodon imperfectus
Ecology: ground dwelling herbivore