formation

Material of the dinosaur Bahariasaurus ingens (1-4, 7-18, 24-26) and indeterminate theropods (5-6, 19-23) from the Bahariya Formation of Egypt.

Arcovenator escotae (Theropoda, Abelisauridae), braincase (MHNAix-PV 2011-12) in dorsal view (Lower Argiles Rutilantes Formation, Jas Neuf Sud, Var)

Left ilium of Stokesosaurus clevelandi, Madsen 1974 (UMNH VP 7473), Morrison Formation, Utah, USA, Late Jurassic (early Tithonian).

Dentary of Echinodon becklesii from the Lower Cretaceous Purbeck Formation of England. Left dentary (NHMUK 48215b) in lateral (A), medial (B), and dorsal (C) views.

Dentary of Echinodon becklesii from the Lower Cretaceous Purbeck Formation of England. Left dentary (NHMUK 48215b) in lateral (A), medial (B), and dorsal (C) views.

Comparison of cranial features between closely related southern Laramidian taxa; (A), Akainacephalus johnsoni (UMNH VP 20202) from the Late Cretaceous Kaiparowits Formation of Utah; and (B), Nodocephalosaurus kirtlandensis (SMP VP-900) from the Late Cretaceous Kirtland Formation of New Mexico, in left lateral views. Various synapomorphies are shared with N. kirtlandensis (highlighted in black and white arrows) and includes “flaring nostrils”; enlarged, laterally projecting, loreal osteoderms that are situated directly dorsal to the external nares. Other synapomorphies include pyramid-shaped nasal and frontal osteoderms positioned on the dorsal regions of the skull. A number of significant differences have been observed between both specimens; in A. johnsoni, the anterior, and posterior supraorbital bosses form an enlarged element that is somewhat backswept, whereas in N. kirtlandensis, the posterior and anterior supraorbital bosses are clearly defined as individual osteoderms, and are much smaller in size. Additionally, the squamosal horn in Akainacephalus is very small but is prominent and tetrahedrally shaped in Nodocephalosaurus. The quadratojugal horn in Akainacephalus is massive, has a subtriangular morphology in lateral view and projects almost entirely ventral, whereas in Nodocephalosaurus, the quadratojugal horn is smaller and has a typical fin-shaped morphology. Study sites: asob, anterior supraorbital boss; ext naris, external naris; laca, lacrimal caputegulum; loca, loreal caputegulum; naca, nasal caputegulae; orb, orbit; psob, posterior supraorbital boss; qjh, quadratojugal horn; sqh, squamosal horn.

Tooth of cf. Zapsalis, with close up of denticles. Specimen UALVP 49582 from the Milk River Formation.

Digital illustration of the Sauropod Dinosaur Isisaurus colberti from the Late Cretaceous (Maastrichtian) of India (72.2-66 MYA). References include Jain & Bandyopadhyay (1997), several papers from Wilson et al. and skeletal reconstruction by Scott Hartman. Illustrated by Ansh Saxena. About Isisaurus– Isisaurus colberti (=Titanosaurus colberti) was a species of Titanosaurian Sauropod Dinosaur from the Late Cretaceous (Maastrichtian) age in the Indian Subcontinent. Isisaurus lived sympatrically with another Titanosaurian Sauropod Jainosaurus. It also lived alongside Theropods like Rajasaurus, Rahiolisaurus, Indosuchus etc. Remains of Isisaurus come from the Lameta formation of Central India.

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.

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.