Dromiceiomimus (Greek for "emu mimic"); pronounced DROE-mih-SAY-oh-MIME-us
Plains of North America
Late Cretaceous (80-65 million years ago)
Size and Weight:
About 12 feet long and 200 pounds
Relatively large eyes and brain; long legs; bipedal posture
A close relative of the North American ornithomimids ("bird mimic" dinosaurs) Ornithomimus and Struthiomimus, the late Cretaceous Dromiceiomimus may have been the fastest of the bunch, at least according to one analysis of this theropod's unusually long legs. At full tilt, Dromiceiomimus may have been capable of hitting speeds of 45 or 50 miles per hour, though it probably stepped on the gas pedal only when it was being pursued by predators or itself in pursuit of small, skittering prey. Dromiceiomimus was also notable for its relatively large eyes (and correspondingly big brain), which matched up oddly with this dinosaur's weak, toothless jaws. As with most ornithomimids, paleontologists speculate that Dromiceiomimus was omnivorous, feeding mostly on insects and vegetation but pouncing on the occasional small lizard or mammal when the opportunity presented itself.
Now for the catch: many, if not most, paleontologists believe that Dromiceiomimus was actually a species of Ornithomimus, and not deserving of genus status. When this dinosaur was discovered, in Canada's Alberta province in the early 1920's, it was initially classified as a species of Struthiomimus, until Dale Russell reexamined the remains in the early 1970's and erected the genus Dromiceiomimus ("emu mimic"). A few years later, though, Russell changed his mind and "synonymized" Dromiceiomimus with Ornithomimus, arguing that the main feature distinguishing these two genera (the length of their legs) wasn't truly diagnostic. Long story short: while Dromiceiomimus persists in the dinosaur bestiary, this difficult-to-spell dinosaur may soon go the way of Brontosaurus!