Simplify the following text for a Grade 10 native English-speaking person.
Original: Sinosauropteryx prima is among the smallest known non-avian theropods , with the type specimen ( a nearly mature individual ) measuring only 68 c in length , including a very long tail .
Simplified: It is among the smallest known non-avian theropods , with the holotype specimen measuring only 68 c in length , including the tail .