The
type species,
Hypsibema crassicauda, was described by
Edward Drinker Cope, and was found in
Sampson County, North Carolina in 1869. The generic name is derived from Greek υψι/
hypsi, "high", and βεμα/
bema, "step", as Cope believed that the species walked particularly erect on its toes. The
specific name means "with a fat tail" in
Latin. The syntypic series, USNM 7189, originally consisted of a caudal vertebra, a metatarsal, and two femoral fragments that were originally identified as humeral and tibial fragments, all found in 1869 by North Carolina state
geologist professor
Washington Carruthers Kerr in the
Black Creek Group of North Carolina. A second vertebra referred to the species, USNM 6136, was later discovered by
Edward Wilber Berry and referred to
H. crassicauda in 1942. In their 1979 review of dinosaur remains from the Black Creek Group, Baird and Horner (1979) noted that the femoral fragments come from a
tyrannosauroid similar to
Dryptosaurus, and made the caudal vertebra included in the syntype series of
H. crassicauda the
lectotype, while stating that the metatarsal could not belong to the same individual as the caudal. Remains assignable to
H. crassicauda have also been reported from the
Ellisdale Fossil Site of New Jersey. although Chase Brownstein considers
Parrosaurus valid and distinct from
Hypsibema based on new discoveries at the
holotype site. It has sometimes been theorized that
Hypsibema represents an adult
Hadrosaurus, which it coexisted with at the sites where it is known, but morphological differences, especially in the vertebrae, support both being distinct taxa. == Description ==