Sinosauropteryx
"Sinosauropteryx" was a small theropod with an unusually long tail and short arms. The longest known specimen reaches up to in length, with an estimated weight of It was a close relative of the similar but older genus "Compsognathus", both genera belonging to the family Compsognathidae. Only one species of "Sinosauropteryx" has been named: "S. prima", meaning "first" in reference to its status as the first feathered non-avialian dinosaur species discovered. Three specimens have been described. The third specimen previously assigned to this genus represents either a second, as-yet unnamed species or a distinct, related genus.
Dinosaur size
There were larger dinosaurs, but knowledge of them is based entirely on a small number of fragmentary fossils. Most of the largest herbivorous specimens on record were discovered in the 1970s or later, and include the massive titanosaur "Argentinosaurus huinculensis", which is the largest dinosaur known from uncontroversial evidence, estimated to have been and long. Some of the longest sauropods were those with exceptionally long, whip-like tails, such as the "Diplodocus hallorum" (formerly "Seismosaurus") and the 33- to 35-metre-long (108–115 ft) "Supersaurus". The tallest was the "Brachiosaurus".