Did the sinosauropteryx fly?
871655#22
Despite its feathers, most palaeontologists do not consider "Sinosauropteryx" to be a bird. Phylogenetically, the genus is only distantly related to the clade Aves, usually defined as "Archaeopteryx lithographica" plus modern birds. The scientists who described "Sinosauropteryx", however, used a character-based, or apomorphic, definition of the Class Aves, in which any animal with feathers is considered to be a bird. They argued that the filamentous plumes of "Sinosauropteryx" represent true feathers with a rachis and barbs, and thus that "Sinosauropteryx" should be considered a true bird. They classified the genus as belonging to a new biological order, Sinosauropterygiformes, family Sinosauropterygidae, within the subclass Sauriurae. These proposals have not been accepted, and "Sinosauropteryx" is generally classified in the family Compsognathidae, a group of small-bodied long-tailed coelurosaurian theropods known from the Late Jurassic and Early Cretaceous of Asia, Europe, and South America.
Sinosauropteryx
871655#13
Longrich's conclusions were supported in a paper first published online in the journal "Nature" in January 2010. Fucheng Zhang and colleagues examined the fossilized feathers of several dinosaurs and early birds, and found evidence that they preserved melanosomes, the cells that give the feathers of modern birds their colour. Among the specimens studied was a previously undescribed specimen of "Sinosauropteryx", IVPP V14202. By examining melanosome structure and distribution, Zhang and colleagues were able to confirm the presence of light and dark bands of colour in the tail feathers of "Sinosauropteryx". Furthermore, the team was able to compare melanosome types to those of modern birds to determine a general range of colour. From the presence of phaeomelanosomes, spherical melanosomes that make and store red pigment, they concluded that the darker feathers of "Sinosauropteryx" were chestnut or reddish brown in colour. More research on the coloration of "Sinosauropteryx" reveals that it had a raccoon-like bandit mask and countershading patterns most likely associated with an open habitat, indicating that the Jehol likely had a range of habitat types.
Sinosauropteryx
871655#0
Sinosauropteryx (meaning "Chinese reptilian wing", ) is a compsognathid dinosaur. Described in 1996, it was the first dinosaur taxon outside of Avialae (birds and their immediate relatives) to be found with evidence of feathers. It was covered with a coat of very simple filament-like feathers. Structures that indicate colouration have also been preserved in some of its feathers, which makes "Sinosauropteryx" the first non-avialian dinosaurs where colouration has been determined. The colouration includes a reddish and light banded tail. Some contention has arisen with an alternative interpretation of the filamentous impression as remains of collagen fibres, but this has not been widely accepted.
Sinosauropteryx
871655#26
The possible "Sinosauropteryx" specimen GMV 2124 ("Sinosauropteryx?" sp.) was found with three mammal jaws in its gut region. Hurum, Luo, and Kielan-Jaworowska (2006) identified two of these jaws as belonging to "Zhangheotherium" and the third to "Sinobaatar", showing that these two mammals were part of the animal's diet. "Zhangheotherium" is known to have had a spur on the ankle, like the modern platypus, which would indicate that "Sinosauropteryx" fed on possibly venomous mammals.
Sinosauropteryx
871655#25
The specimen NIGP 127587 was preserved with the remains of a lizard in its gut region, indicating that small, fast-moving animals made up part of the diet of "Sinosauropteryx prima". Numerous lizards of this type have been found in the same rocks as "Sinosauropteryx". These lizards have been interpreted as most likely belonging to the genus "Dalinghosaurus". "Dalinghosaurus" was probably a fast-running lizard adapted to living in open habitats, much like "Sinosauropteryx" itself.
Sinosauropteryx
871655#14
The first fossil specimen of the dinosaur later named "Sinosauropteryx prima" was uncovered in August 1996 by Li Yumin. Yumin was a farmer and part-time fossil hunter who often prospected around Liaoning Province to acquire fossils to sell to individuals and museums. Yumin recognized the unique quality of the specimen, which was separated into two slabs, and sold the slabs to two separate museums in China: the National Geological Museum in Beijing, and the Nanjing Institute of Geology and Paleontology. The director of the Beijing museum, Ji Qiang, recognized the importance of the find, as did visiting Canadian palaeontologist Phil Currie and artist Michael Skrepnick, who became aware of the fossil by chance as they explored the Beijing museum's collections after leading a fossil tour of the area during the first week of October, 1996. Currie recognized the significance of the fossil immediately. As "The New York Times" quoted him, "When I saw this slab of silt stone mixed with volcanic ash in which the creature is embedded, I was bowled over." When originally described, the authors named "Sinosauropteryx", meaning "Chinese Reptilian Wing".
Sinosauropteryx
871655#23
Below is a cladogram showing the placement of "Sinosauropteryx" within Coelurosauria by Senter "et al." in 2012.
There is only one named species of "Sinosauropteryx", "S. prima". A possible second species is represented by the specimen GMV 2124 (aka NGMC 2124), which was described as a third, larger specimen of "S. prima" by Ji and Ji in 1997. However, in a 2002 presentation and abstract for the Society of Vertebrate Paleontology, Nick Longrich showed that this specimen differs in several anatomical aspects from the others, including its relatively large size, proportionally longer shins, and shorter tail. Longrich suggested that GMV 2124 was a compsognathid coelurosaurian, while "Sinosauropteryx" proper was a more primitive kind of coelurosaurian or even a basal carnosaurian. In 2007, Gishlick and Gauthier concurred that this specimen was probably a new taxon, and tentatively re-classified it as "Sinosauropteryx?" sp., though they suggested it may belong in a new genus. Also in 2007, Ji, Ji and colleagues wrote that GMV 2124 is probably a new genus, noting the differences in tail length and hindlimb proportions.
Sinosauropteryx
871655#11
While "Sinosauropteryx" had feather-like structures, it was not very closely related to the previous "first bird" "Archaeopteryx". There are many dinosaur clades that were more closely related to "Archaeopteryx" than "Sinosauropteryx" was, including the deinonychosaurians, the oviraptorosaurians, and the therizinosauroids. This indicates that feathers may have been a characteristic of many theropod dinosaurs, not just the obviously bird-like ones, making it quite likely that equally distant animals such as "Compsognathus" had feathers as well.
Sinosauropteryx
32398527#3
In 2010 Dr. Mike Benton from the University of Bristol analyzed the remains of "Sinosauropteryx", "Confuciusornis", "Caudipteryx", and "Sinornithosaurus" from the Yixian and also discovered melanosomes. It was determined that "Sinosauropteryx" had orange feathers and that its tail was striped. Given the feathers were brightly colored and ill-suited for flight it is hypothesized that this species used its feathers for display. A 2017 study also reported that the body coloration of "Sinosauropteryx" extended to the face, creating a raccoon-like "mask" around the eyes.
Dinosaur coloration
871655#17
Controversy regarding the identity of the filaments preserved in the first "Sinosauropteryx" specimen began almost immediately, as the team of scientists spent three days in Beijing examining the specimen under a microscope. The results of their studies (reported during a press conference at the Philadelphia Academy of Natural Sciences on Thursday, April 24, 1997) were inconclusive; the team agreed that the structures preserved on "Sinosauropteryx" were not modern feathers, but suggested further research was required to discover their exact nature. Palaeontologist Alan Feduccia, who had not yet examined the specimen, wrote in "Audubon Magazine" that the structures of "Sinosauropteryx" (which he considered at the time to be a synonym of "Compsognathus", as "Compsognathus prima") were stiffening structures from a frill running along the back, and that dinosaur palaeontologists were engaging in wishful thinking when equating the structures with feathers. Subsequent publications saw some of the team members disagreeing over the identity of the structures.
Sinosauropteryx