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. Phylogenetic studies did not support the idea that NGMC 91 was a close relative of S. millenii. In a 2004 analysis, Phil Senter and colleagues found that it was, in fact, more closely related to Microraptor. Subsequent studies, also by Senter, have continued to show support for this finding despite the fact that some data used in the original study was later found to be flawed. However, in a 2011 publication Senter stated that a personal examination of the holotype of S. millenii led him to conclude that his earlier separation of NGMC 91 from S. millenii was based on anatomical misinterpretations. As the two specimens were "identical in all character states" used in his phylogenetic analysis, were from similar stratigraphic levels and "uniquely share the presence of a triangular coracoid with a large, oval foramen", Senter concluded that NGMC 91 does belong to the species Sinornithosaurus millenii. The same conclusion was also reached independently from Senter by Turner, Makovicky and Norell (2012). According to these authors, NGMC 91 shares several apomorphies with both Microraptor zhaoianus and Sinornithosaurus millenii; however, as it "lacks elongate middle caudals that are three to four times the length of the dorsal vertebrae", it cannot be referred to M. zhaoianus. On the other hand, it does possess a posteriorly bifurcated dentary, which is an apomorphy of Sinornithosaurus. The authors concluded that NGMC 91 was a subadult specimen of S. millenii. Cladogram (2012): Discovery and specimens Sinornithosaurus was discovered by Xu Xing, Wang Xiaolin and Wu Xiaochun of the Institute of Vertebrate Paleontology and Paleoanthropology of Beijing. An almost-complete fossil with feather impressions, was recovered from Liaoning Province, China, in the Yixian Formation; the same incredibly rich location where four dinosaurs with feathers were discovered previously, Protarchaeopteryx, Sinosauropteryx, Caudipteryx, and Beipiaosaurus. Sinornithosaurus was the first dromaeosaurid discovered with feathers. The holotype specimen is IVPP V12811, in the collection of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China. The NGMC 91 specimen is in the collection of the National Geological Museum of China. It was collected in Fanzhangzi quarry, near Lingyuan City, Liaoning Province. This location is part of the Dawangzhangzi fossil beds, which have been dated to about 122 million years