crâne

Reconstructed skull of Einiosaurus procurvicornis on display at the Natural History Museum of Los Angeles County.

Kronosaurus queenslandicus (QM F18827; proposed neotype [part]) skull in dorsal view (modified from McHenry Citation2009). Scale = 30 cm.

Brontotholus is a relatively large pachycephalosaurian dinosaur. Like all pachycephalosaurs, it was bipedal and sported the characteristic bony dome on top of its skull. Brontotholus grew to nearly 4 m in length, making it one of the largest known pachycephalosaurs, and the largest from the Campanian age.

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.

Fossil samples – e.g. ‘primitive’ bony fish (1, 2), a skull of a temnospondyl ‘amphibian’ (probably a metoposauroid) in dorsal view (3), a skull of an archosaur of the crocodile lineage (probably a phytosaur) in palatal view (4), holotype of the “gliding reptile” Icarosaurus siefkeri [1] (5) and Atreipus-Grallator-type dinosaur tracks (bottom right) – from the Newark Supergroup, i.e. a series of mainly Late Triassic to Early Jurassic sedimentary rocks of eastern North America ↑ Edwin H. Colbert: A gliding reptile from the Triassic of New Jersey. American Museum Novitates, 2230. American Museum of Natural History, New York 1966, digitallibrary.amnh.org, cf. fig. 3 therein.

Type skull of Pentaceratops sternbergii, American Museum of Natural History # AMNH6325

Science Museum - Carcharodontosaurus Skull - 2014

Science Museum - Carcharodontosaurus Skull - 2014

Hypothetical Plesiolophus skull reconstruction with known elements in white. Missing elements in grey. Scale bar 20 cm.

Brontotholus is a relatively large pachycephalosaurian dinosaur. Like all pachycephalosaurs, it was bipedal and sported the characteristic bony dome on top of its skull. Brontotholus grew to nearly 4 m in length, making it one of the largest known pachycephalosaurs, and the largest from the Campanian age.

Fossil skull of Luskhan

Skeletal reconstruction of Heyuannia yanshini (previously Ajancingenia yanshini). Specimens as: blue: MPC-D 100/30 (holotype); green: MPC-D 100/31; red: MPC-D 100/32; tan: MPC-D 100/20 (holotype skull of Conchoraptor gracilis).

Crâne de Ajancingenia yanshini. Mongolie.

Ajancingenia mounted cast (labeled as Ingenia), detail of skull, on display at the Museum of Ancient Life, Utah.

The skull of Janusaurus lundi (PMO 222.654). A: Photo in right lateral view of the skull. B: Right lateral view with interpretation of the individual elements. Abbreviations: a, angular; art, articular; d, dentary; en, external naris; j, jugal; l, lacrimal; mx, maxilla; n, nasal; or, orbit; p, parietal; pmx, premaxilla; po, postorbital; pof, postfrontal; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; st, supratemporal. Scale = 5 cm.

Beg tse - skull and drawing. a Skull in lateral view. b Schematic drawing of skull in left lateral view. Abbreviations: af, antorbital fossa; an, angular; de, dentary; fr, frontal; j, jugal; la, lacrimal; mx, maxilla; na, nasal; or, orbit; pd, predentary; pf, prefrontal; pm, premaxilla; po, postorbital; qu, quadrate; sa, surangular.