Some days we just have busy morning. Coelurus does not mind at all. As long as I get to introduce him to everyone I strongly doubt that Coelurus would care. The genus Coelurus consists of one species, Coelurus fragilis, though it does have two synonymous names; C. agilis and Elaphrosaurus agilis. Elaphrosaurus is a rather odd name, though it sounds interesting, and I for one am glad that it was the junior to Coelurus and not the other way around (Coelurus Marsh 1879 versus Elaphrosaurus Marsh 1884). Elaphrosaurus, just to avoid confusion, has been raised since that time (Janensch 1920) as an ceratosaurine genus; more about Elaphrosaurus in the future though. Meaning "hollow tail" Coelurus' description was a product of what has come to be called the "Bone Wars" of the 19th century between Marsh and Cope. As such, it was not given much thought after it was named and described. A full year of quarrying, September 1879 to September 1880, revealed many different aspects of the skeleton of Coelurus, but the passage of time and the disassociated elements lead to confusion and the misidentification of the remains as belonging to more than one species, thus the synonymy that is present now. Cope and Lydekker also named species of Coelurus, only to have them changed later to other genera; Cope redescribing the two Coelurus specimens he had named as belonging to Coelophysis and Lydekker's specimen being transferred to Thecospondylus. Thankfully, however, all of that misinformation and confusion has been cleared today and we recognize, and know, a single species of hollow-tailed fragile dinosaur as Coelurus fragilis.