Size and Weight:
As you can guess from its name, Similicaudipteryx closely resembled one of the prototypical "dino-birds" of the Cretaceous period, Caudipteryx, which also lived in Asia. What set this seven-syllable dinosaur apart from its more famous namesake was its pygostyle, the small, feathered structure, supported by bone, at the end of its tail--a feature shared by modern peacocks and by only one other known feathered dinosaur, Nomingia.
Pygostyle aside, Similicaudipteryx has become famous thanks to the recent, detailed research of Chinese paleontologists, who claim (based on the analysis of two associated fossils) that juveniles of this species had a different feather structure than adults--which implies that this feathered dinosaur molted like modern birds. However, it's notoriously difficult to draw firm conclusions from hundred-million-year-old feather impressions, and not all experts are convinced that the differences are as pronounced as the scientists say.