Crétacé

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.

Hypothetical reconstruction of the Late Cretaceous abelisaurid Elemgasem nubilus.

Riojavenatrix: "La Rioja huntress" Early Cretaceous, Europe

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.

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.

Diagram featuring the holotype (BNMNH-PV030) skull of the troodontid Papiliovenator neimengguensis, from the Bayan Mandahu Formation. Abbreviations: a, angular; d, dentary; f, frontal; j, jugal; l, lacrimal; m, maxilla; n, nasal; p, parietal; q, quadrate; s, surangular; sp, splenial.[1] References ↑ (2022). "A new troodontid from the Upper Cretaceous Gobi Basin of inner Mongolia, China". Cretaceous Research 130: Article 105052. DOI:10.1016/j.cretres.2021.105052.

Skull of troodontid theropod Xixiasaurus henanensis gen. et sp. nov. (HGM 41HIII−0201; holotype), lower–middle Majiacun Formation (Upper Cretaceous: Coniacian–Campanian), Henan Province, China; in dorsal (A); lateral (B), and ventral (C) views. Note that this version of the image does not include the interpretative lines of the version in the paper.

Life reconstruction of the Late Cretaceous south american paravian, Overoraptor chimentoi

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

Alvarezsauridae gen. et sp. indet., posterior caudal vertebrae. Dzharakuduk, Uzbekistan; Bissekty Formation, Upper Cretaceous (Turonian). a-e, ZIN PH 2441/16, two vertebrae preserved in articulation, in anterior (a), dorsal (b), posterior (c), lateral (d), and ventral (e) views. f-j, ZIN PH 2442/16, vertebra missing ventral part of the centrum, in dorsal (f), lateral (g), ventral (h), anterior (i), and posterior (j).

Ceratonykus oculatus, Late Cretaceous of Mongolia. Digital.

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

Skull diagram featuring the holotype skull (ROM 1790) of the ornithomimid Rativates evadens, from the Late Cretaceous period. Abbreviations: d, dentary; f, frontal; l, lacrimal; m, maxilla; n, nasal; pm, premaxila; ps, paraphenoid.

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.

Ornithischian dinosaur Stenopelix valdensis Meyer, 1857, holotype (GZG 741/2, formerly GPI Gö 741−2), from the Obernkirchen Sandstone (Early Cretaceous: Berriasian), near Bückeburg, Niedersachsen, Germany. A. Large sandstone slab. B. Interpretative outline drawing of large latex cast (prepared from large sandstone slab), showing majority of postcranial skeleton in dorsal view. C. Small sandstone slab. D. Interpretative outline drawing of small la− tex cast (prepared from small sandstone slab), showing sacrum and caudals, pelvic region and partial hindlimbs in ventral view. For clarity elements in and around the sacral region have not been labelled—these areas are shown in greater detail in Fig. 3. Roman numerals II–IV correspond to respective digits. Abbreviations: mt, metatarsals; f, femur; ?, unidentified element.

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