Ornithopods: from early forms to duck-billed dinosaurs

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• Aralosaurus: Kazakhstan's early crested hadrosaur

  Aralosaurus tuberiferus from the Bostobe Formation: its incomplete skull, nasal crest, changing classification and the limits of its life reconstruction.

• Amurosaurus: the hadrosaur from the Amur bonebed

  Amurosaurus riabinini from the Amur region: its Blagoveshchensk bonebed, type specimen, disputed Sahaliyania synonymy, size estimates and incomplete crest.

• Mantellisaurus: a lightly built European iguanodont

  A detailed Mantellisaurus profile covering the nearly complete Isle of Wight skeleton, its naming history, anatomy, size and uncertain relationships.

• Tethyshadros: a small-bodied dinosaur from Italy

  Tethyshadros insularis from Italy: Antonio and Bruno, the Villaggio del Pescatore fossils, anatomy, growth, diet and the disputed dwarf-island idea.

• Atlascopcosaurus: what a jaw fragment can establish

  Atlascopcosaurus loadsi is anchored by a maxilla from Victoria’s Early Cretaceous Eumeralla Formation. Later fossil finds broaden the Australian ornithopod record, but they do not turn the type into a complete skeleton.

• Nipponosaurus: the young lambeosaurine from Sakhalin

  Nipponosaurus is known from one juvenile skeleton found on Sakhalin. Bone histology confirms its age, while a 2017 reanalysis separates growth-related traits from features that may diagnose the genus.

• Oryctodromeus: a dinosaur linked to a fossil burrow

  An adult and two juveniles were preserved in a sediment-filled burrow in Montana. Burrow dimensions and digging-related anatomy support Oryctodromeus as the maker, while family life and exact behaviour remain interpretations.

• Probactrosaurus: before the duck-billed dinosaurs

  A detailed profile of Probactrosaurus gobiensis, its Maortu fossils, debated age, tooth batteries, species history and place near the origin of hadrosauroids.

• Prosaurolophus: a hadrosaurid with a low nasal crest

  Prosaurolophus is represented by numerous skulls from Alberta and Montana. Their variation helps test how its low nasal crest changed with age and whether the named species P. blackfeetensis is distinct.

• Protohadros: the Texan dinosaur named the first hadrosaur

  Protohadros is based mainly on a damaged skull from the Cenomanian Woodbine Formation of Texas. Its downturned snout is real anatomy; its exact feeding range and position near Hadrosauridae remain matters of interpretation.

• Rhabdodon: a robust ornithopod of Late Cretaceous Europe

  A detailed Rhabdodon profile covering the type jaw, changing species names, French fossils, size, diet and the limits of its European range.

• Secernosaurus: a hadrosaurid from southern Patagonia

  Secernosaurus is known from incomplete fossils in Patagonia and later referred material. Revisions of the type, changing formation names and competing hypotheses about related South American hadrosaurids shape what can be said about it.

• Telmatosaurus: a revised hadrosauroid from Transylvania

  Telmatosaurus is anchored by a crushed skull from the Hațeg Basin. A 2026 revision narrowed the secure fossil list and placed it with Tethyshadros and Kryptohadros in a proposed southeastern European clade.

• Thescelosaurus: a sturdy dinosaur near the end of the Cretaceous

  Meet Thescelosaurus, a sturdy Late Cretaceous ornithischian known from western North America, and see what its fossils reveal about anatomy and possible ecology.

• Yandusaurus: a damaged Jurassic fossil and a shifting family tree

  Yandusaurus hongheensis is known from a damaged partial skeleton from Zigong, China. Its original species Y. multidens was transferred to Hexinlusaurus; the type species remains difficult to place within Neornithischia.

• Zalmoxes: what remains of a once broader genus

  Zalmoxes robustus is based on Late Cretaceous fossils from Romania. A 2026 reassessment changed the status of the former second species Z. shqiperorum and left the placement of Z. robustus uncertain, so older summaries of the genus need qualification.

• Zephyrosaurus: a distinctive skull, a very incomplete skeleton

  Zephyrosaurus schaffi was named from a fragmentary skull and associated bones from Montana’s Cloverly Formation. Its distinctive skull features support comparison with other small ornithischians, while proposed trackmakers, burrowing habits and a complete body reconstruction remain uncertain.

• Ornithopods and hadrosaurs: a broader group and one branch

  Hadrosaurids are one branch of the broader ornithopod group. Compare their classification, beaks, tooth batteries and fossil evidence without treating the names as synonyms.

• Lambeosaurines and Saurolophines: two duck-billed dinosaur branches

  Compare the hollow nasal crests of lambeosaurines with the varied skull ornaments of saurolophines, and learn why hadrosaurid names and relationships remain nuanced.

• Brachylophosaurus: what Leonardo’s fossil preserves

  Brachylophosaurus canadensis is known from skulls, articulated skeletons and the exceptional specimen Leonardo. Its skin impressions and possible gut contents reveal both the power and limits of fossil preservation.

• Eolambia: an early relative of duck-billed dinosaurs

  Explore Eolambia caroljonesa through its Cedar Mountain fossils, changing classification, growth evidence, estimated size and Cretaceous floodplain habitat.

• Equijubus: an early hadrosauroid from China

  Equijubus normani is an Early Cretaceous ornithopod from Gansu, known from a complete skull and partial skeleton. Its dental fossils preserve a rare association with early grass microfossils.

• Fukuisaurus: the Japanese Early Cretaceous ornithopod

  A fossil-based guide to Fukuisaurus tetoriensis, its Kitadani skull material, disputed relationships, estimated size and life in Early Cretaceous Japan.

• Gasparinisaura: skull anatomy, swallowed stones and a changing family tree

  Gasparinisaura cincosaltensis is represented by several specimens from Argentina’s Anacleto Formation. CT-based skull work published in 2026 and fossil gastroliths add evidence, while its exact relationships and growth remain debated.

• Gilmoreosaurus: a revised name built from scattered bones

  Gilmoreosaurus mongoliensis was first named Mandschurosaurus mongoliensis from fossils collected by the Central Asiatic Expeditions. A 2010 redescription revised its type material and diagnosis; the age of the Iren Dabasu beds remains contested.

• Gryposaurus: a nasal arch, a tooth battery and a changing taxonomy

  Gryposaurus is a North American hadrosaurid recognised by a raised nasal profile. Multiple species and specimens preserve variation in the skull and skin, while the limits of each species remain a taxonomic question.

• Jaxartosaurus: the crest is mostly missing

  Jaxartosaurus aralensis is a lambeosaurine hadrosaur from Kazakhstan, anchored by a partial skull roof and braincase. Its crest, body and exact age are less certain than many reconstructions imply.

• Jinzhousaurus: one skeleton, several rounds of description

  Jinzhousaurus yangi is represented by a largely complete individual from Liaoning. Later preparation and study revised its cranial diagnosis and expanded knowledge of its postcranial skeleton.

• Lurdusaurus: a heavy-built ornithopod from Niger

  Lurdusaurus explained through its partial skeleton, thick limb bones, quadrupedal gait, size estimates and the evidence against a specialised semi-aquatic life.

• Leaellynasaura: a polar dinosaur with a fragmentary fossil record

  Leaellynasaura is based chiefly on a partial skull from Early Cretaceous Victoria. Its high-latitude setting is secure, but the famous long-tailed reconstruction and claims about night vision rely on material or interpretations that remain disputed.

• Olorotitan: a long-necked hadrosaur from the Amur region

  Olorotitan arharensis from Kundur: its nearly complete skeleton, hollow crest, long neck, disputed species and the limits of size and behaviour estimates.

• Dinosaur sounds: what fossils can tell us

  What hollow crests, skull scans and living bird and crocodile comparisons can suggest about dinosaur sound, and why no fossil lets us hear an exact call.

• Asian dinosaur discoveries from the Gobi to China

  From the Central Asiatic Expeditions and the Flaming Cliffs to Chinese feathered dinosaurs and modern Mongolian fieldwork, follow discoveries across Asia.

• Hypacrosaurus: a hollow-crested hadrosaurid

  Hypacrosaurus explained through H. altispinus fossils, its hollow crest, tall neural spines, growth series and the reassignment of H. stebingeri.

• Shantungosaurus: a giant hadrosaur from China

  A detailed Shantungosaurus profile covering its giant size, Chinese fossils, hadrosaur anatomy, feeding, growth and the limits of its skeletal record.

• Anatosaurus: an obsolete name for Edmontosaurus

  Anatosaurus explained as a historical name for Edmontosaurus annectens, including Anatotitan, skull growth, skin evidence and taxonomic synonymy.

• Parasaurolophus

  A detailed Parasaurolophus guide covering three species, fossils, 8–10 m size, hollow crest anatomy, possible sounds, growth, feeding and locomotion.

• Saurolophus: the solid-crested hadrosaur of two continents

  Saurolophus osborni and S. angustirostris: Canadian and Mongolian fossils, crest growth, skin impressions, hatchlings, diet and uncertain mass estimates.

• Lambeosaurus

  A detailed Lambeosaurus guide covering its two species, 7–9 m size, hatchet-shaped hollow crest, fossils, growth, dental batteries and movement.

• Kritosaurus: the hadrosaur with a missing nose

  Kritosaurus navajovius from New Mexico: its incomplete type skull, the history of the Roman-nosed reconstruction, revised species and uncertain body proportions.

• Edmontosaurus

  A detailed Edmontosaurus guide covering its two species, 9–12 m size, fossils, skin mummies, soft crest, dental batteries, movement and habitat.

• Corythosaurus

  A detailed Corythosaurus guide covering Alberta fossils, 7.5–9 m size, hollow helmet crest, growth, species debate, sound hypotheses and habitat.

• Tsintaosaurus: more than a ‘unicorn’ crest

  Tsintaosaurus spinorhinus from China: its disputed horn-like crest, the 2013 skull revision, uncertain sound claims and incomplete fossil record.

• Hadrosaurus: the historic skeleton with no complete skull

  Hadrosaurus foulkii explained through its 1858 discovery, first museum mount, incomplete holotype, uncertain skull, feeding anatomy and taxonomic debate.

• Bactrosaurus: an early relative of the duck-billed dinosaurs

  Bactrosaurus johnsoni from the Iren Dabasu Formation: discovery, growth, dental batteries, uncertain age and the evidence behind its flat skull.

• Maiasaura

  A detailed Maiasaura guide covering Montana nesting grounds, eggs, hatchlings, 7–9 m adults, rapid growth, parental-care evidence and bonebeds.

• Muttaburrasaurus: a distinctive Cretaceous plant-eater

  A detailed Muttaburrasaurus profile covering Queensland discoveries, its unusual skull, teeth, diet, movement and uncertain species diversity.

• Ouranosaurus: the high-backed ornithopod of Niger

  Explore Ouranosaurus nigeriensis through its two major skeletons, tall neural spines, uncertain soft-tissue outline, size estimates and Early Cretaceous habitat.

• Vectisaurus: an old name from the Isle of Wight

  Vectisaurus is a historical name based on incomplete Early Cretaceous fossils from the Isle of Wight. Later reviews linked its material with Mantellisaurus rather than a separate accepted genus.

• Camptosaurus: a Jurassic ornithopod under revision

  An evidence-led Camptosaurus profile covering its Morrison Formation fossils, changing species list, anatomy, size and plant-based diet.

• Callovosaurus: a Jurassic name anchored to one femur

  Callovosaurus leedsi is based chiefly on one incomplete femur from England’s Middle Jurassic Oxford Clay. Its history from Camptosaurus leedsi to a separate genus illustrates how classification depends on the diagnostic value of a single bone.

• Iguanodon

  A detailed Iguanodon guide covering the Bernissart skeletons, classification, 8–10 m size, teeth, thumb spike, locomotion and changing reconstructions.

• Iguanodonts and the rise of large herbivorous dinosaurs

  Iguanodontians were a long-lived branch of ornithopod dinosaurs. Their fossils record changes in size, teeth and locomotion, while the limits of the group remain debated.

• Pisanosaurus

  Pisanosaurus mertii from Argentina's Ischigualasto Formation: the single PVL 2577 specimen, herbivorous teeth, body-size limits and competing placements among ornithischians and silesaurids.

• Lycorhinus: jaws, caniniforms and a changing classification

  Follow Lycorhinus from a jaw first mistaken for a cynodont to a recognised heterodontosaurid, and see what its teeth can reveal.

• Heterodontosaurids and their unusual teeth

  Heterodontosaurids were small ornithischian dinosaurs with distinctive combinations of teeth. Their skulls offer clues to feeding, but diet and family-tree placement remain under study.

• Echinodon: a heterodontosaurid known from its jaws

  Echinodon becklesii is an Early Cretaceous dinosaur from Dorset known from fragmentary jaws. Explore its lectotype, teeth, classification and limits of reconstruction.

• Scutellosaurus: an early dinosaur with small armour plates

  Scutellosaurus lawleri was a small Early Jurassic thyreophoran from Arizona. Learn what its osteoderms, skeletons, growth and habitat can establish.

• Lesothosaurus: a small dinosaur with a complicated family tree

  Lesothosaurus is a small Early Jurassic ornithischian known from skulls and skeletons in Lesotho and South Africa. CT scans, histology and changing phylogenetic analyses have refined – and complicated – its story.

• Fabrosaurus: what three teeth can tell us

  Fabrosaurus australis is based on a jaw fragment from Lesotho. Learn what MNHN LES9 shows, why the name is doubtful and how it relates to Lesothosaurus.

• Tenontosaurus: a long-tailed Early Cretaceous ornithopod

  Explore Tenontosaurus anatomy, growth, two recognised species and the evidence behind fossils found with Deinonychus teeth.

• Fulgurotherium: one fragment behind a disputed name

  Fulgurotherium australe is based on one opalised femoral fragment from Lightning Ridge. Its changing classification and doubtful diagnostic status show why a real fossil may not support a secure species-level identification.

• Hypsilophodon: the small ground-dwelling ornithischian

  Explore Hypsilophodon foxii through Isle of Wight fossils, growth, teeth and movement, and learn why the tree-climbing and armour myths are wrong.

• Dryosaurus: the lightly built Morrison ornithopod

  Learn about Dryosaurus species, Morrison fossils, growth, teeth and movement, and why the genus's maximum size remains uncertain.

• Hypsilophodonts: a historical name for early ornithischians

  “Hypsilophodonts” is often used for small early ornithischians, but the traditional family Hypsilophodontidae is not consistently recovered as one natural group.

• Ornithischian dinosaurs: a branch with many forms

  Explore ornithischian anatomy and the diversity of stegosaurs, ankylosaurs, ornithopods, hadrosaurs, ceratopsians and pachycephalosaurs, with the limits of their family tree.

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