Coloradisaurus brevis was originally named Coloradia brevis by José Bonaparte in 1978, but that genus name was preoccupied by the pine moth Coloradia, so it needed a replacement name. In 1983, David Lambert used the name Coloradisaurus for the genus, but did not indicate it was a replacement or diagnose it. Lambert had gotten the name from Bonaparte in a personal communication and mistakenly thought that Bonaparte had already published it.
The original name for the dinosaur *Coloradisaurus* was "Coloradia brevis" given by José Bonaparte in 1978, but this name was taken by another species of moth.  David Lambert used the name *Coloradisaurus* in 1983, but did not clarify that it replaced the previous name or diagnose it. He got the name from Bonaparte through a personal conversation and thought Bonaparte had already published it.