Hypsibema

Cope, 1869 HIP-see-BEE-ma Nomen dubium

From Greek hypsi (high) and bema (step); meaning 'high step', because Edward Cope believed the animal walked particularly erect on its toes

83.6–72.2 million years ago Campanian, Late Cretaceous

Late Cretaceous stages

Hypsibema is a dubious genus of very large dinosaur from the Late Cretaceous of eastern North America, of uncertain affinities. The type species, H. crassicauda, is known mainly from the Tar Heel Formation of North Carolina and the Marshalltown Formation of New Jersey, and its fragmentary material has been interpreted as sauropod as well as hadrosaurian. A second species, H. missouriensis from the Maastrichtian of Missouri, was originally named Neosaurus and then Parrosaurus before being referred to Hypsibema by Baird and Horner (1979); Brownstein (2018) returns it to Parrosaurus.

Under dispute

Baird and Horner (1979) restricted Hypsibema crassicauda to a lectotype caudal, the type series being a mixture of three suborders, and referred it to Sauropoda, a placement later work rejects. Prieto-Márquez and colleagues (2016) list H. crassicauda and the Missouri species among the nondiagnostic Appalachian hadrosaurids, while Brownstein (2018) treats both as valid giant hadrosauroids, the Missouri species as Parrosaurus missouriensis, of uncertain placement within or outside Hadrosauridae. It is placed at Hadrosauroidea incertae sedis.

Species (2)

Hypsibema crassicauda Cope, 1869 Nomen dubium

Type species

From Latin 'crassus' meaning 'thick' or 'fat' and 'cauda' meaning 'tail', together meaning 'with a fat tail', in reference to the massively constructed tail of the species.

Holotype: USNM 7189 , National Museum of Natural History, Smithsonian Institution
Material: Humerus, tibia, fibula, metatarsus, caudal vertebra, cervical vertebrae, ungueal phalange
Horizon: Black Creek Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality: Marl pits of James King, North Carolina, United States

Hypsibema missouriensis (Gilmore & Stewart, 1945) Disputed

First named as Neosaurus missouriensis

Named for Missouri, the U.S. state where the holotype was discovered, with the Latin suffix '-ensis'.

Holotype

USNM 16735 , National Museum of Natural History, Smithsonian Institution

Material

13 caudal centra and two unidentified fragments; all neural arches missing

Horizon

McNairy Sand Member, Ripley Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago

Locality

Chronister farm, Missouri, United States

Diagnosis

Caudal centra amphicoelous, longer than wide, with angularly rounded sides shallowly concave from end to end
Articular ends with a flattened peripheral border surrounding a concave central area bearing radiating bumps and depressions
Sides of the centra divided subequally by a low longitudinal ridge that fades posteriorly
Chevron facets restricted to the posterior ends of the centra, the ventral surface scooped out between them

Synonyms

Neosaurus missouriensis reassigned

Original combination (Gilmore and Stewart, 1945); the genus name Neosaurus was preoccupied.
Parrosaurus missouriensis reassigned

Combination under Parrosaurus, the replacement name Gilmore (1945) coined for the preoccupied Neosaurus; referred to Hypsibema by Baird and Horner (1979).

Synonyms of the genus

Name	Type	Reason
Neosaurus	preoccupied	Name preoccupied by Neosaurus (Reptilia).
Parrosaurus	reassigned	Coined by Gilmore (1945) as a replacement for the preoccupied Neosaurus; its type species was referred to Hypsibema by Baird and Horner (1979). Brownstein (2018) uses Parrosaurus missouriensis.

References

Cope, E. D. (1869). [Remarks on Eschrichtius polyporus, Hypsibema crassicauda, Hadrosaurus tripos, and Polydectes biturgidus]. Proceedings of the Academy of Natural Sciences of Philadelphia 21: 191-192.
Records the type material from Sampson County, North Carolina, of Cretaceous age but intrusive in Miocene beds, without a closer locality.
cope1869a
Gilmore, C. W.; Stewart, D. R. (1945). A new sauropod dinosaur from the Upper Cretaceous of Missouri. Journal of Paleontology 19(1): 23-29. https://www.jstor.org/stable/1299165
Original description of the type material, as the sauropod Neosaurus missouriensis.
gilmore1945a
Gilmore, C. W. (1945). Parrosaurus, n. name, replacing Neosaurus Gilmore, 1945. Journal of Paleontology 19(5): 540. https://www.jstor.org/stable/1299009
Replacement genus name (Parrosaurus) for the preoccupied Neosaurus Gilmore, 1945.
gilmore1945b
Baird, D.; Horner, J. R. (1979). Cretaceous dinosaurs of North Carolina. Brimleyana 2: 1-28. https://www.biodiversitylibrary.org/part/442233
Referred Parrosaurus missouriensis to Hypsibema. Traces the type material of H. crassicauda to the marl pits of James King in Sampson County, in the "blue marl", now the Black Creek Formation.
baird1979a
Horner, J. R. (1979). Upper Cretaceous dinosaurs from the Bearpaw Shale (marine) of south-central Montana with a checklist of Upper Cretaceous dinosaur remains from marine sediments in North America. Journal of Paleontology 53(3): 566-577.
Lists the type of Parrosaurus missouriensis, now this genus's second species, as USNM 16733; Gilmore (1945) prints U.S.N.M. 16735.
horner1979b
Prieto-Márquez, A.; Erickson, G. M.; Ebersole, J. A. (2016). Anatomy and osteohistology of the basal hadrosaurid dinosaur Eotrachodon from the uppermost Santonian (Cretaceous) of southern Appalachia. PeerJ. PeerJ.
Lists Hypsibema crassicauda and Parrosaurus missouriensis among the nondiagnostic hadrosaurids of the Appalachian record.
prieto-márquez2016b
Brett-Surman, M. K. (1989). A revision of the Hadrosauridae (Reptilia: Ornithischia) and their evolution during the Campanian and Maastrichtian. 1-272. Doctoral thesis, The George Washington University.
Finds none of the elements diagnostic and calls Hypsibema a nomen dubium, questioning its transfer to Sauropoda.
brett-surman1989a
Brownstein, C. D. (2018). The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia. Palaeontologia Electronica 21.1.5A: 1-56. doi:10.26879/801
Treats Hypsibema crassicauda and the Missouri species, as Parrosaurus missouriensis, as valid giant hadrosauroids of uncertain placement within or outside Hadrosauridae.
brownstein2018a