Cretaceous

Speculative reconstruction of Aoniraptor'’ from the Late Cretaceous of Argentina, here restored as a megaraptoran as recovered by most studies

Garumbatitan is a sauropod dinosaur from the Early Cretaceous of what is now Spain. It is classified as a basal somphospondylan - a Titanosauriform, but not a true Titanosaur.

Braincase of WSC 10058, holotype of Ornatops Braincase of Ornatops incantatus in digital 3D model in right lateral (A and C) and left lateral (D and F) views, with enlarged images of the right (B) and left (E) auditory regions. Credit: McDonald AT, Wolfe DG, Freedman Fowler EA, Gates TA. 2021. A new brachylophosaurin (Dinosauria: Hadrosauridae) from the Upper Cretaceous Menefee Formation of New Mexico. PeerJ 9:e11084 https://doi.org/10.7717/peerj.11084

The hadrosaurid dinosaur Wulagasaurus dongi gen. et sp. nov. from the Upper Cretaceous Yuliangze Formation at the Wulaga quarry, China. A. Holotype GMH W184, right dentary in lateral (A1) and medial (A2) views. B. GMH W217, right dentary in lateral (B1) and medial (B2) views.

Holotype of the polycotylid[1] plesiosaur Edgarosaurus muddi DRUCKENMILLER, 2002, (MOR 751) comprising the skull, the neck, and the left front flipper, on display in the Museum of the Rockies in Bozeman, Montana. The specimen was collected in Edgar, Carbon County, Montana, from the Shell Creek member of the Thermopolis Shale Formation, Upper Albian, uppermost Lower Cretaceous.[2]

Closeup of the camellate pneumaticity inside the vertebrae of Vectiraptor greeni, from the Early Cretaceous of the Isle of Wight, UK. Photo by Nick Longrich.

Ningchengopterus liuae, early Cretaceous of China. digital.

A skull reconstruction and cranial bones from Shaochilong maortuensis, a small-bodied mid Cretaceous (Turonian) carcharodontosauri-an theropod from Inner Mongolia, China. A, skull reconstruction (courtesy of Brett Booth); B, right maxilla in lateral view (IVPP V.2885.4); C, braincase and skull roof in dorsal view (IVPP V.2885.1-2). Scale bars equal 5 centimeters.

Abelisaurid theropod Kryptops palaios gen. et sp. nov. MNN GAD1−1 from the Lower Cretaceous Elrhaz Formation of Niger. Left maxilla in lateral view; stereopair (A) and line drawing (B). Cross−hatching indicates broken bone; dashed lines indicate estimated edges.

Ceratopsipes goldenensis Lockley & Hunt, 1995 - ceratopsian dinosaur trackway in the Cretaceous of Colorado, USA. Ceratopsians are the "horned dinosaurs". They were large, quadrupedal, herbivorous dinosaurs having a beaked skull and a frill - an extension of bone behind the skull that partially covered the neck. Ceratopsian dinosaurs are known from the Jurassic and Cretaceous. The last members of the group died out at the Cretaceous-Tertiary boundary, 65 million years ago. Seen here is a ceratopsian dinosaur trackway. Ceratopsian footprints are very rare. The best examples are in Colorado's Laramie Formation, a nonmarine, coastal plain to deltaic succession of mostly mixed siliciclastic sedimentary rocks - sandstones, siltstones, claystones, and coals. The footprints here consist of convex bulges on the basal surfaces of structurally-tilted sandstone beds. The ichnospecies Ceratopsipes goldenensis was named based on footprints at this locality. The trackmaker was very likely Triceratops, the # 1 most famous ceratopsian dinosaur. From on-site signage: Triceratops Tracks Several tracks of Triceratops, or a closely related horned dinosaur were first discovered in this area and named Ceratopsipes goldenensis (meaning tracks of a horned dinosaur from Golden). By happy coincidence, the first Triceratops known to science also comes from the greater Denver area near 13th Avenue and Federal Blvd. Growing to a length of almost 25 feet, Triceratops and other members of the horned dinosaur family were herbivorous animals that roamed in herds. Their trademark horns and frills that covered their necks probably served for defense. A replica Triceratops skull is on display in the clubhouse at the Fossil Trace Golf Club. These tracks (identified by small signs) help us understand that Triceratops walked with a narrow gait and erect front limbs than with a wide, sprawling gait as previously depicted. In 1887, the first Triceratops bones known to science were also discovered locally at a site near 13th Avenue and Federal Boulevard in Denver. Nearby one may see many other traces of life such as burrows, probably made by invertebrates and impressions of plant debris. Note that you are looking at all tracks and traces from the underside - in negative aspect - what one might call a worm’s eye view. All of these trace fossils indicate that the Golden area once had a warm, temperate to subtropical climate. Classification: Animalia, Chordata, Vertebrata, Reptilia, Archosauria, Dinosauria, Ornithischia, Marginocephalia, Ceratopsia, Ceratopsidae Stratigraphy: Laramie Formation, Maastrichtian Stage, upper Upper Cretaceous Locality: outcrop along Triceratops Trail, Parfet Prehistoric Preserve, southern side of the town of Golden, Colorado, USA (~vicinity of 39° 44' 35.24" North latitude, 105° 13’ 09.69" West longitude) Some info. from: Lockley & Hunt (1995) - Ceratopsid tracks and associated ichnofauna from the Laramie Formation (Upper Cretaceous: Maastrichtian) of Colorado. Journal of Vertebrate Paleontology 15: 592-614.

Left maxilla (A) and left dentary (B) of carcharodontosaurid theropod Kelmayisaurus petrolicus Dong, 1973 (IVPP V 4022, China, Lianmugin For− mation, Lower Cretaceous). Photographs in lateral (A1, B1), medial (A2, B2), ventral (A3), and dorsal (B3) views. Scale bars 5 cm. Designation “d” refers to dentary tooth, designation “m” refers to maxillary tooth position. Dorsal view of dentary shows tooth row only.

Left ilium of the camarasauromorph sauropod Brontomerus mcintoshi from the Lower Cretaceous Cedar Mountain Formation of Utah, type specimen OMNH 66430 in lateral view reconstructed from the three fragments (A), and ventral view (B).

Forearm and hand of Machairasaurus leptorhynchos Longrich et al. 2010 (Dinosauria: Theropoda: Oviraptoridae: Ingeniinae) from the Late Cretaceous Djadokhta Formation beds of Bayan Mandahu, Inner Mongolia, China. Digital photography and editing by Nick Longrich

Hypothetical reconstruction of the Late Cretaceous abelisaurid Elemgasem nubilus.

Spinosaurus aegyptiacus, a spinosaurid from the Middle Cretaceous of Egypt

Spinosaurus aegyptiacus, a spinosaurid from the Middle Cretaceous of Egypt