Pronunciation: HIP-see-BEE-ma
Meaning: High stepper
Author/s: E.D. Cope (1869)
Synonyms: See below
First Discovery: North Carolina, U.S.A.
Acta Ordinal: #30
Hypsibema crassicauda
Based on a tail vertebra, a piece of upper arm, a calf, a shin and a partial foot bone—found in James King's marl pits of North Carolina by Washington Carruthers Kerr in 1869—Edward Drinker Cope named Hypsibema crassicauda—"thick-tailed, high-stepper"—assuming its affinities lay close to Hadrosaurus, and that its odd-shaped foot bone suggested a critter that walked, ballerina-like, on its tippy-toes.
Because of fragmentary remains, Hypsibema was, and still is, a bit obscure; its appearance left to cautious inference rather than confident reconstruction. Not even Lull and Wright's 1942 hadrosaurian magnum opus could make much sense of it. Hypsibema lay low until 1979, when Baird and Horner reidentified the arm bone and now-missing shin as tyrannosauroid thigh fragments, reinterpreted the calf bone as a shin and judged it—like the foot bone—worthless, trimmed the type series to one tail vertebra, and classified Hypsibema crassicauda as a sauropod. Their conclusions leaned heavily on material from farther west—most notably richer finds in Missouri—which they also assigned to Hypsibema, but as a second species.
Upon initial inspection of these remains—later identified as coming from the Ripley Formation—Charles Gilmore supposed they belonged to a modestly sized sauropod and, in 1945, he named them Neosaurus missouriensis. As it turned out, Nopcsa had already attached Neosaurus to a pelycosaur—Neosaurus cynodus, which is a taxonomic odyssey in and of itself, so the name was changed to Parrosaurus later that year in honour of Albert Eide Parr. Unfortunately, Gilmore died soon after, leaving the material in limbo for many years.
Baird and Horner revisited the bones in 1979 and lumped Parrosaurus into Hypsibema as Hypsibema missouriensis, arguing that the vertebrae and tail proportions matched those of Hypsibema crassicauda. It wasn’t until further discoveries in the 1980s—by Stinchcomb, Parris, and Grandstaff at the Chronister farm, now owned by Stinchcomb—that the animal's true family ties came into focus. Cope was right: Hypsibema was a giant duck-billed hadrosaur.
Despite several name changes, reassignments, and ongoing debate, Hypsibema missouriensis was still adopted by Missouri as their official state dinosaur in 2004, largely because there weren't many other contenders. Several palaeontologists have since questioned whether Hypsibema missouriensis should be assigned to Hypsibema at all and have suggested reverting to Parrosaurus.
Because of fragmentary remains, Hypsibema was, and still is, a bit obscure; its appearance left to cautious inference rather than confident reconstruction. Not even Lull and Wright's 1942 hadrosaurian magnum opus could make much sense of it. Hypsibema lay low until 1979, when Baird and Horner reidentified the arm bone and now-missing shin as tyrannosauroid thigh fragments, reinterpreted the calf bone as a shin and judged it—like the foot bone—worthless, trimmed the type series to one tail vertebra, and classified Hypsibema crassicauda as a sauropod. Their conclusions leaned heavily on material from farther west—most notably richer finds in Missouri—which they also assigned to Hypsibema, but as a second species.
Hypsibema missouriensis
Discovered in lumps of clay by Lulu Chronister and her family while digging a well in 1942 near Glen Allen, a total of thirteen huge vertebrae eventually found their way to the Smithsonian via "Dinosaur Dan" and a $50 sweetener that the Chronisters used to secure the services of a cow.Upon initial inspection of these remains—later identified as coming from the Ripley Formation—Charles Gilmore supposed they belonged to a modestly sized sauropod and, in 1945, he named them Neosaurus missouriensis. As it turned out, Nopcsa had already attached Neosaurus to a pelycosaur—Neosaurus cynodus, which is a taxonomic odyssey in and of itself, so the name was changed to Parrosaurus later that year in honour of Albert Eide Parr. Unfortunately, Gilmore died soon after, leaving the material in limbo for many years.
Baird and Horner revisited the bones in 1979 and lumped Parrosaurus into Hypsibema as Hypsibema missouriensis, arguing that the vertebrae and tail proportions matched those of Hypsibema crassicauda. It wasn’t until further discoveries in the 1980s—by Stinchcomb, Parris, and Grandstaff at the Chronister farm, now owned by Stinchcomb—that the animal's true family ties came into focus. Cope was right: Hypsibema was a giant duck-billed hadrosaur.
Despite several name changes, reassignments, and ongoing debate, Hypsibema missouriensis was still adopted by Missouri as their official state dinosaur in 2004, largely because there weren't many other contenders. Several palaeontologists have since questioned whether Hypsibema missouriensis should be assigned to Hypsibema at all and have suggested reverting to Parrosaurus.
Etymology
Described by Edward Drinker Cope in 1869, Hypsibema is derived from the Greek "hypsi" (high) and "bema" (step), a reference to its odd-shaped metatarsal which Cope assumed made it walk "more directly on its toes".
The species epithet, crassicauda, means "thick tail" in Latin. The species epithet, missouriensis, means "from Missouri" in Latin.
Discovery
The first remains of Hypsibema crassicauda were discovered in the Tar Heel Formation of the Black Creek Group (previously called the Black Creek Formation) in James King's marl pits of Sampson County, North Carolina, by state geologist Washington Carruthers Kerr in 1869. The holotype (USNM 7189) originally consisted of one tail vertebra, a piece of humerus and tibia that turned out to be tyrannosauroid femur fragments, a fibula that turned out to be a tibia, and a metatarsal.
Only the vertebra remains, as the lectotype. A second vertebra (USNM 6136), discovered by Edward Wilber Berry at Phoebus Landing, Bladen County, in 1907, was cited erroneously as cotype and referred to Hypsibema crassicauda by Lull and Wright in 1942.
A very large partial hadrosaur humerus (UNC 5735), found in the Tar Heel Formation at Milepost 49, Bladen County, by Everett Brett and Walter H. Wheeler, was described by Baird and Horner in 1979. An estimated complete length of 830 mm suggests a behemoth hadrosaurid, perhaps upwards of fifteen meters long and twelve tons in weight, which would plonk it almost in the same league as Asia's colossus, Shantungosaurus.
Remains assignable to Hypsibema crassicauda have also been reported from the Ellisdale Fossil Site of New Jersey. The first remains of Hypsibema missouriensis were discovered in the McNairy sand member of the Ripley formation at Chronister Farm near Glen Allen, Bollinger County, Missouri, USA, in the early spring of 1942 by Mrs. Lulu Chronister, during the digging of a well which was abandoned when sufficient water was not found. The holotype (USNM 16735) is a series of 13 tail vertebrae and two unidentified fragments. A fourteenth vertebra was given to a relative by Mrs. Chronister but hasn't been seen since.
Excavations Chronister farm are ongoing.
