Utahraptor ostrommaysi
Pound for pound, Utahraptor ostrommaysi might have been the most ferocious predator of all time. It might have been Utahraptor spielbergi too, but a certain film director — mentioning no Steven Spielberg names — turned out to be "all talk and no action", and when financial support for the Utah digs failed to materialise, Jim Kirkland pulled the plug and opted to honour John Ostrom and Chris Mays instead.
(Ostrom and May's Utah Plunderer)
Etymology
Utahraptor is derived from "Utah" (its place of discovery) and the Latin "raptor" (plunderer or thief). The species epithet, ostrommaysi, honours John Ostrom from Yale University's Peabody Museum of Natural History and Chris Mays of Dinamation International.
In 2000, George Olshevsky amended the Latin singular ostrommaysi to ostrommaysorum in line with Latin plural rules, as it honours both Ostrom and Mays. But that rule is only enforced by the ICZN (International Commission on Zoological Nomenclature) when two or more people share the same first or last name, for example: degrootorum for John and Sandra DeGroot. Therefore, ostrommaysi stands.
Discovery
Jim Jensen found the first remains of what would later become Utahraptor in the Dalton Wells Quarry of the Cedar Mountain Formation near Moab town, east-central Utah, in 1975, but they barely raised an eyebrow. However, the discovery of a claw by Carl Limoni at Gaston Quarry (CMF) during the excavation of Gastonia in October 1991, similar to those on the second toes of Deinonychus and Velociraptor but much bigger, piqued the interest of James Kirkland, Robert Gaston and Donald Burge, who discovered more remains in the Yellow Cat and Poison Strip members of the same quarry later that year. Yes, both Gaston Quarry and Gastonia honour Robert Gaston.
The holotype (CEUM 184v.86) is a foot claw from digit II which suggests an animal about twice the size of Deinonychus, and Utahraptor was long reconstructed as a similarly agile predator. However, the discovery of perhaps a dozen specimens in a fossilised sandtrap at Utah's Stikes Quarry showed that Utahraptor was incredibly robust and stocky, with a huge head, short torso, tall spines on its back vertebrae for anchoring wads of muscle, and remarkably powerful legs.
Many more specimens have since been assigned to Utahraptor, including a toe claw
(CEUM 184v.294), a shin (CEUM 184v.260) and the tip of an upper jawbone (CEUM 184v.400) that might pertain to the holotype, and more remain entombed in stone blocks awaiting their appointment with the preparator. But some are not what they initially appeared to be. What were previously identified as hand claws of the specimens M184v.294, BYU 9438 and BYU 13068 are toe claws, while a skull bone (CEUM 184v.83: also potentially part of the holotype) turned out to belong to a different dinosaur entirely: the nodosaur Gastonia.
Some as-yet undescribed specimens in the collections of Brigham Young University are rumoured to belong to a critter almost eleven meters long. That length has been explained away by some experts as a gross overestimate due to several different aged critters being jumbled together, which cunningly ignores the presence of bones large enough to proffer such an estimate in the first place.
