An incredibly well-preserved microraptorian nicknamed "Dave" (specimen NGMC 91), was first described in a paper published in the journal "Nature" by Ji Qiang and colleagues in 2001. They declined to name the specimen because, although it is completely articulated, almost all of the bones shattered when the fossil slabs were split, so that only the silhouettes of these bones are clear in most of the part and counterpart. This obscured diagnostic skeletal features, which made the specimen's genus uncertain. They noted that it was similar in some respects to "Sinornithosaurus millenii", and they suggested that the differences between the two could have been due to age. Ji, along with another team of scientists, further emphasized this similarity in a 2002 paper, in which they formally referred the specimen to "Sinornithosaurus", though they considered the exact species questionable. Meanwhile, Stephen Czerkas and colleagues considered the specimen to represent an example of their newly described species "Cryptovolans pauli" (now usually considered a synonym of "Microraptor gui"), based on supposed wing proportions.