Dinosauria

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Duck-billed dinosaurs at the Royal Ontario Museum. A Maiasaura skeleton is visible on the foreground, with two Maiasaura juveniles at the foot of the skeletal mount. On the background, flushing with the wall, there's the two-dimensional mount of a Gryposaurus specimen. The unidentified skull of another duck-billed dinosaur is visible on the low right corner of the photograph.

Duck-billed dinosaurs at the Royal Ontario Museum. A Maiasaura skeleton is visible on the foreground, with two Maiasaura juveniles at the foot of the skeletal mount. On the background, flushing with the wall, there's the two-dimensional mount of a Gryposaurus specimen. The unidentified skull of another duck-billed dinosaur is visible on the low right corner of the photograph.

Six examplar sauropods (top to bottom): Patagotitan at the Field Museum of Natural History, Barosaurus at the American Museum of Natural History, Giraffatitan at the Museum fur Naturkunde, Omeisaurus tianfuensis at the Zigong Dinosaur Museum, Shunosaurus, and Amargasaurus

Six maniraptoran dinosaurs (top to bottom): the Zamyn Khondt oviraptorosaur, Sinornithosaurus, the Alaskan troodontid, Patagonykus, a short-tailed albatross, Nothronychus

Map of Cretaceous-aged dinosaur fossil localities of Mongolia. Gobihadros mongoliensis was collected from Bayshin Tsav in Area C. Open squares indicate Late Cretaceous sites, solid squares represent Early Cretaceous localities. Abbreviations: A, Localities of Western Gobi Desert in Mongolia, mainly group of localities of Nemegtian age (early Maastrichtian), Late Cretaceous; B, Localities of Central Gobi Desert in Mongolia, mainly Djadokhtian age (Campanian), Late Cretaceous; C & D- Localities of Eastern Gobi Desert in Mongolia, mainly Baynshirenian age (Cenomanian-Santonian), Late Cretaceous. Figure has been modified from Tsogtbaatar et al. 2014, Figure 1 [24].

Restoration of the spinosaurid dinosaur Siamosaurus in the Sao Khua Formation palaeoenvironment, with Sunosuchus in the middle left and a herd of Phuwiangosaurus in the background. References: Siamosaurus based on tooth specimens [1] and the neural spine of a possibly referable skeleton[2], with other missing elements filled in with relatives (Suchomimus[3], Baryonyx[4], IchthyovenatorFile:Ichthyovenator_laosensis_skeletal_reconstruction_by_PaleoGeek.png). Phuwiangosaurus based on skeletal by Suteethorn et al. (2009)[5] and missing elements of skull of EuhelopusFile:Euhelopus.png. Sunosuchus based on Suteethorn and Ingavat (1983)[6] and missing elements based on Goniopholis[7].

Dinosaur Park Formation in Dinosaur Provincial Park, Alberta

The distictive banding of the Morrison Formation, a group of rock layers that occur throughout Dinosaur National Monument. The formation originated as muds and sands laid down by ancient rivers, and some of its outcrops have been found to contain 150-million-year-old dinosaur fossils like those found at the monument's Dinosaur Quarry.

Wide angle photo from the visitor’s walkway inside Lark Quarry Dinosaur Trackways, Australia. Here, the camera is pointing towards the south west corner of the building. On the top (in the far corner) is the natural landscape. In the middle ground of the photo, some of the overburden has been cleared. In the foreground is the dinosaur tracks.

The Natural Science Museum at El Chocón, in the northwestern Argentine Patagonia (the Comahue region). Fossil of dinosaur

historická budova Národního muzea v Praze - západní dvorana s proskleným stropem a kostrou dinosaura / historic building of the National Museum in Prague - West hall with glass ceiling and dinosaur skeleton location: Prague, Czech Republic author: Jan Helebrant www.juhele.blogspot.com license CC0 Public Domain Dedication

Nyasasaurus is a basal dinosauromorph that may be the earliest known dinosaur. It was a small bipedal animal at about 2-3 m in length. Nyasasaurus is difficult to classify due to inconclusive fossil evidence, but if it is a true dinosaur, it pushes the dinosaur lineage back about 12 million years to the Middle Triassic.

Sidersaura is a rebbachisaurid sauropod dinosaur from the Late Cretaceous of Argentina. Rebbachisaurids are the last known dipldocoids, and lived alongside the titanosaurs until fairly late in the Cretaceous before disappearing from the fossil record, presumably going extinct. They have long tails and relatively short necks, by sauropod standards. Sidersaura one of the most recent rebbachisaurids yet found, living in the Cenomanian–Turonian ages of the Late Cretaceous. It was large for a rebbachisaurid, growing to about 20 m in length.

Fossil of Mei long (holotype), on temporary display at the Shanghai Natural History Museum as part of the exhibition "China's Dinosaur World". Shot on July 22, 2025.

Achelousaurus horneri skull, collected in Glacier County, Montana, at the Museum of the Rockies in Bozeman, Montana. The Ceratopsidae are those dinosaurs with head frills. There are three large subgroups of Ceratopsidae: Centrosaurinae, Ceratopsinae, and Chasmosaurinae. The Triceratopsini are a "tribe" of the Chasmosaurinae -- a genus so vast that it gets the special name "tribe". The Pachyrhinosaurini are a "tribe" within the Centrosaurinae. Achelousaurus is a genus within the Pachyrhinosaurini. So far, only three skulls and some limited skeletal remains have been collected anywhere in the world -- and all of them in Montana. Their bony frills are quite similar to the Styracosaurus albertensis, although their other skull features (such as big bony bosses on the nose and behind the eyes) are not.