Foremost

Becklespinax altispinax holotype BMNH R1828 (originally assigned to Megalosaurus bucklandii). Owen's description follows: Three anterior dorsal vertebræ : p, parapophysis, or lower transverse process: t, accessory tubercle contributing some attachment to the head of the rib : d, diapophyses, or upper transverse process, fractured, which gave attachment to the tubercle of the rib: b, oblique buttress extending from the parapophysis to the diapophysis, and contributing to the support of the neural platform : z, the prozygapophysis, z', the zygapophysis, forming the ends of the neural platform and articulating the neural arches of the vertebræ with each other, ns, the neural spine of the foremost of these vertebras, ns', the neural spine of the second vertebra; it expands at its extremity, overhangs the anterior shorter spine, and developes a strong bony plate from its back part which fixes it to n", the similarly developed and modified spine of the third vertebra. The extraordinary size and strength of the spines of these anterior dorsal vertebræ, indicate the great force with which the head and jaws of the Megalosaurus must have been used. From the Wealden, near Battle. In the Museum of Samuel H. Beckles, Esq., F.G.S.

Becklespinax altispinax holotype BMNH R1828 (originally assigned to Megalosaurus bucklandii). Owen's description follows: Three anterior dorsal vertebræ : p, parapophysis, or lower transverse process: t, accessory tubercle contributing some attachment to the head of the rib : d, diapophyses, or upper transverse process, fractured, which gave attachment to the tubercle of the rib: b, oblique buttress extending from the parapophysis to the diapophysis, and contributing to the support of the neural platform : z, the prozygapophysis, z', the zygapophysis, forming the ends of the neural platform and articulating the neural arches of the vertebræ with each other, ns, the neural spine of the foremost of these vertebras, ns', the neural spine of the second vertebra; it expands at its extremity, overhangs the anterior shorter spine, and developes a strong bony plate from its back part which fixes it to n", the similarly developed and modified spine of the third vertebra. The extraordinary size and strength of the spines of these anterior dorsal vertebræ, indicate the great force with which the head and jaws of the Megalosaurus must have been used. From the Wealden, near Battle. In the Museum of Samuel H. Beckles, Esq., F.G.S.

Geographic and stratigraphic relationships of the holotype EMK 0012 and the Loki Quarry in northern Montana. (A) Regional relationships between the cross-border paleontological sites in the Oldman and Judith River formations along the Milk River and in Kennedy Coulee in Alberta and Montana. (B) Generalized stratigraphic section in the Kennedy Coulee area modified after Goodwin & Deino (1989) and Rogers, Eberth & Ramezani (2023) with the relationships between the Foremost and Oldman formations in Canada and the Judith River Formation in Montana. Relative placements of important taxa in this area are indicated. Position of 40Ar/39Ar dates originally obtained by Goodwin & Deino (1989) are shown in relation to the new U–Pb CA-ID-TIMS date for KC061517-1 by Ramezani et al. (2022). Bentonite ash beds are only 5 to 7 cm thick so they are exaggerated for clarity. Scale bars delineated in map view are indicated kilometers and in meters stratigraphically.

Outcrops of the Foremost Formation along the Milk River.