The holotype
femur and
tooth were discovered by
Carlos Ameghino, Florentino's brother, between 1887 and 1898. Ameghino named this dinosaur in 1899 from a
proximal femur (MACN-1629) and tooth found near
Rio Sehuen, Santa Cruz, in the
Cardiel Formation Upon further review, von Zittel assigned it to the
Coeluridae, recognized today as a "
wastebasket taxon" for small
carnivorous dinosaurs. The carnivore tooth helped this misidentification take hold. It was ignored for decades until
Ralph Molnar reassessed it. He found that the tooth did not belong to the same animal as the femur and removed it from the type, and suggested that the femur belonged to a
hypsilophodont or
turtle. Professional opinion has not changed much since then, although based on size, it appears more likely to be an
iguanodont than a hypsilophodont. a view which has not been followed since. == Paleobiology ==