joined the expedition in 1987. This reflected the fact that the expedition members had started to take the possibility into account that the species was completely new to science, informally referring to it as "Styracosaurus makeli" in honour of Bob Makela, who had died in a traffic accident in June 1987. In 1990, this name, as an invalid nomen nudum because it lacked a description, appeared in a photo caption in a book by Stephen Czerkas. Horner was an expert on the Hadrosauridae, several sites of which had also been discovered in Landslide Butte, including the juveniles and eggs that were the focus of his research. He had less affinity for other kinds of dinosaurs. In 1987 and 1989, to resolve the Styracosaurus question, horned dinosaur specialist Peter Dodson was invited to investigate the new ceratopsian finds. In 1990, the fossil material was seen by Dodson as strengthening the case for the validity of a separate Styracosaurus ovatus, to be distinguished from Styracosaurus albertensis. Horner had gradually changed his mind on the subject. While still thinking that a single population of horned dinosaurs had been present, he began to see it as a chronospecies, an evolutionary series of taxa. In 1992, he described them in an article as three "transitional taxa" that had spanned the gap between the older Styracosaurus and the later Pachyrhinosaurus. He deliberately declined to name these three taxa. The oldest form was indicated as "Transitional Taxon A", mainly represented by skull MOR 492. Then came "Taxon B" – the many skeletons of the Dinosaur Ridge Quarry and the Canyon Bone Bed. The youngest was "Taxon C", represented by skull MOR 485 found in 1987 and the horned dinosaur fossils of the Blacktail Creek North. Sampson names Einiosaurus In 1994, Sampson, in a talk during the annual meeting of the Society of Vertebrate Paleontology, named Horner's "Taxon B" as a new genus and species, Einiosaurus procurvicornis. Although an abstract was published containing a sufficient description, making the name valid, it did not yet identify by inventory number a holotype, a name-bearing specimen. The same abstract named Type C as Achelousaurus horneri. In 1995, Sampson published a larger article, indicating the holotype. The generic name Einiosaurus is derived from the Blackfeet eini, "American bison", and Latinised Greek saurus, "lizard". The name was chosen to honour the Blackfeet tribe but also to reflect the fact that ceratopsids were, in