formation

Skeletal reconstructions of Dinosaur Park Formation caenagnathids. Skeletal reconstructions of Citipes elegans (left), Chirostenotes pergracilis (middle), and Caenagnathus collinsi (right), showing variation in skeletal representation and body size. Previously referred material is indicated in white and newly referred material is indicated in red for each taxon. Blue asterisks indicate elements that have been histologically sampled for each taxon. Citipes elegans: dentaries, metatarsal IV; Chirostenotes pergracilis: dentaries, tibia; Caenagnathus collinsi: pubis.

Pterodactylus compressirostris, holotype NHMUK PV 39410 (Cenomanian / Turonian, Chalk Formation). A–D proposed lectotype, fragment of the mandibular symphysis A left lateral view B respective line drawing C dorsal view D respective line drawing. E–H referred specimen, portion of the rostrum E left lateral view F respective line drawing G ventral view H respective line drawing. Abbreviations: ch – choanae, d – dentary, m – maxillae, naof – nasoantorbital fenestra, pl – palatine, pm – premaxillae, prid – palatal ridge, sul– sulcus. Arrows indicate alveoli or teeth. Scale bar = 10 mm. Photos courtesy of The Natural History Museum.

Pterodactylus compressirostris, holotype NHMUK PV 39410 (Cenomanian / Turonian, Chalk Formation). A–D proposed lectotype, fragment of the mandibular symphysis A left lateral view B respective line drawing C dorsal view D respective line drawing. E–H referred specimen, portion of the rostrum E left lateral view F respective line drawing G ventral view H respective line drawing. Abbreviations: ch – choanae, d – dentary, m – maxillae, naof – nasoantorbital fenestra, pl – palatine, pm – premaxillae, prid – palatal ridge, sul– sulcus. Arrows indicate alveoli or teeth. Scale bar = 10 mm. Photos courtesy of The Natural History Museum.

Pterodactylus compressirostris, holotype NHMUK PV 39410 (Cenomanian / Turonian, Chalk Formation). A–D proposed lectotype, fragment of the mandibular symphysis A left lateral view B respective line drawing C dorsal view D respective line drawing. E–H referred specimen, portion of the rostrum E left lateral view F respective line drawing G ventral view H respective line drawing. Abbreviations: ch – choanae, d – dentary, m – maxillae, naof – nasoantorbital fenestra, pl – palatine, pm – premaxillae, prid – palatal ridge, sul– sulcus. Arrows indicate alveoli or teeth. Scale bar = 10 mm. Photos courtesy of The Natural History Museum.

Right dentary of Zalmoxes shqiperorum holotype NHMUK R4900in dorsal and lateral views, from the Sinpetru Formation of Sânpetru (Romania; outline based on the specimen UBB NVZ1-1).

Holotype specimen of Hylaeosaurus armatus Mantell, 1833 (NMH R3775) from the Grinstead Clay Formation (late Valanginian) of Tilgate Forest, Sussex, southern England.

Holotype specimen of Hylaeosaurus armatus Mantell, 1833 (NMH R3775) from the Grinstead Clay Formation (late Valanginian) of Tilgate Forest, Sussex, southern England.

The nodosaurid dinosaur, Glyptodontopelta is mostly known from isolated osteoderms ("armor plates"). The specimen SMP VP-1580 (State Museum of Pennysylvania) is however, the most complete known specimen, comprising parts of the skull, hundreds of osteoderms and fragments. This specimen was discovered in 2003 by Warwick Fowler, in the Naashoibito Member of the Ojo Alamo Formation (Maatrichtian, Late Cretaceous) of the San Juan Basin, New Mexico, during an expedition led by Dr. Robert Sullivan.

Figure description from the paper: "The segmented model of right lateral side of the skull of mixosaurid ichthyosaur Phalarodon fraasi (Merriam, 1910) PMO 235.393, from the Botneheia Formation, Middle Triassic of the Isfjorden area in Spitsbergen, Svalbard." References: Roberts, A.J.; Engelschiøn, V.S.; Hurum, J.H. (2022). "First three-dimensional skull of the Middle Triassic mixosaurid ichthyosaur Phalarodon fraasi from Svalbard, Norway". Acta Palaeontologica Polonica 67 (1): 51–62. DOI:https://doi.org/10.4202/app.00915.2021.

Figure description from the paper: "The segmented model of right lateral side of the skull of mixosaurid ichthyosaur Phalarodon fraasi (Merriam, 1910) PMO 235.393, from the Botneheia Formation, Middle Triassic of the Isfjorden area in Spitsbergen, Svalbard." References: Roberts, A.J.; Engelschiøn, V.S.; Hurum, J.H. (2022). "First three-dimensional skull of the Middle Triassic mixosaurid ichthyosaur Phalarodon fraasi from Svalbard, Norway". Acta Palaeontologica Polonica 67 (1): 51–62. DOI:https://doi.org/10.4202/app.00915.2021.

Dinosaur eggs (Dendroolithus sp.) from Kaoguo Formation, Henan, China, on display at the San Diego County Fair, California, USA.

Dinosaur eggs (Dendroolithus sp.) from Kaoguo Formation, Henan, China, on display at the San Diego County Fair, California, USA.

Drawing of lectoholotype skull BMNH R.3386 (desigated by Weishampel et al., 1993)[1][2] of Limnosaurus transsylvanicus NOPCSA 1900 (later renamed Telmatosaurus transsylvanicus), a basal hadrosaurid dinosaur from the Late Maastrichtian (latest Upper Cretaceous) Sanpetru Formation of West Central Romania.

Right dentary of Zalmoxes robustus holotype NHMUK R3392 in dorsal and lateral views, from the Sinpetru Formation, Sânpetru (Romania)

Tetrapodosaurus borealis footprint from the Dunvegan Formation, Canada.

Coelophysis bauri (Cope, 1887) theropod dinosaur from the Triassic of New Mexico, USA. This is a remarkable complete skeleton of the small early theropod Coelophysis. It comes from a nearly monospecific concentration of numerous complete to disarticulated skeletons in reddish-colored fluvial siltstones, often called a "Coelophysis graveyard". This occurrence has been interpreted as a carcass-jammed channel filling following mass mortality of dinosaurs by regional drought (see Schwartz & Gillette, 1994). Stratigraphy: Rock Point Member, Chinle Formation, Upper Triassic Locality: Whitaker Quarry (Coelophysis Quarry), Ghost Ranch, Rio Arriba County, northern New Mexico, USA Some info. from: Hunt, A.P. & S.G. Lucas. 1991. Rioarribasaurus, a new name for a Late Triassic dinosaur from New Mexico (USA). Paläontologische Zeitschrift 65: 191-198. Schwartz, H.L. & D.D. Gillette. 1994. Geology and taphonomy of the Coelophysis Quarry, Upper Triassic Chinle Formation, Ghost Ranch, New Mexico. Journal of Paleontology 68: 1118-1130. Theropod were small to large, bipedal dinosaurs. Almost all known members of the group were carnivorous (predators and/or scavengers). They represent the ancestral group to the birds, and some theropods are known to have had feathers. Some of the most well known dinosaurs to the general public are theropods, such as Tyrannosaurus, Allosaurus, and Spinosaurus.