Cryptovolans
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| Cryptovolans Fossil range: Early Cretaceous |
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C. pauli Czerkas et al., 2002 (type) |
Cryptovolans (meaning 'hidden flyer') is a genus of feathered, dromaeosaurid, dinosaur represented by a 90 cm long individual preserved in 3 fossils. Feduccia et al. (2005) treated "Cryptovolans" as a junior synonym for Microraptor[1]. If this move was formally adopted the name Cryptovolans would be abandoned.[1] Its specific name, C. pauli, honors paleontologist Gregory S. Paul. This fossil is in the collection of the Paleontology Museum of Beipiao, in Liaoning, China. The type specimens were collected from the Jiufotang Formation. They are referred to as LPM 0200 (or BPM 1 3-13), LPM 0201, and LPM 0159. Norell et al. (2002) were the first to publish a study of the specimens, but they did not assign the animal a formal name.[2] Czerkas et al. (2002) coined the name "Cryptovolans" and diagnosed this genus on the basis of primary feathers (which in the authors' opinion made it a bird), an ossified sternum, and a third finger with a short phalanx III-3. Some of the feathers Czerkas described as primary were actually attached to the leg, rather than the arm. This, along with all of the other diagnostic characters, is also present in the genus Microraptor, which was first described earlier than Cryptovolans.[3]However, BPM 1 3-13 has a longer tail, proportionately, than other Microraptor specimens that had been described by 2002.[2]
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[edit] Study and Debate
Norell et al (2002) described BPM 1 3-13 (nicknaming it "Chong") as the first dinosaur known to have asymmetric, primary flight feathers on its legs as well as on its arms.[4]
Czerkas (2002) mistakenly described the fossil as having no long feathers on its legs, but only on its hands and arms, as he illustrated on the cover of his book Feathered Dinosaurs and the Origin of Flight.[5] In his discussion of "Cryptovolans" in this book, Czerkas strongly denounces Norell's conclusions; "The misinterpretation of the primary wing feathers as being from the hind legs stems directly to seeing what one believes and wants to see" -(sic). In fact, though, multiple specimens of Microraptor have shown that Norell was correct. Czerkas corrected his own mistake in later versions of the art for his traveling exhibit Feathered Dinosaurs and the Origin of Flight'.[1]
Czerkas also denounced Norell for failing to conclude that dromaeosaurs are birds, accusing him of succumbing to "...the blinding influences of preconceived ideas." In fact, though, Norell uses an explicit definition of the term "bird" - as a subset of avialae, which definitely excludes BPM 1 3-13. See Avialae.
Czerkas also believed that Cryptovolans may have been able to fly better than Archaeopteryx, the animal usually referred to as the earliest known bird. He cited the fused sternum and asymmetrical feathers, and argued that Cryptovolans has modern bird features that make it more derived than Archaeopteryx. Czerkas cited the fact that this possibly volant animal is also very clearly a dromaeosaurid to suggest that the Dromaeosauridae might actually be a basal bird group, and that later, larger, species such as Deinonychus were secondarily flightless (Czerkas, 2002). The current consensus is that there is not enough evidence to conclude whether dromaeosaurs descended from an ancestor with some aerodynamic abilities. The work of Xu et al. (2003) suggested that basal dromaeosaurs were probably small, arboreal, and could glide[6]. The work of Turner et al. (2007) suggested that the ancestral dromaeosaurs could not glide or fly, but that there was good evidence that they were small bodied (around 65 centimeters long and 600-700 grams in mass).[7].See Dromaeosauridae, Relationship with Birds.
[edit] References
- ^ a b Feduccia, Alan, Lingham-Soliar, Theagarten, Hinchliffe, J. Richard. "Do feathered dinosaurs exist? Testing the hypothesis on neontological and paleontological evidence" "Journal of Morphology" 266:125-166
- ^ a b Norell, Mark, Ji, Qiang, Gao, Keqin, Yuan, Chongxi, Zhao, Yibin, Wang, Lixia. (2002). "'Modern' feathers on a non-avian dinosaur". Nature, 416: pp. 36. 7 March 2002.>
- ^ Xu, Xing, Zhou, Zhinghe, Wang, Xiaolin, KUang, Xuewen, Zhang, Fucheng, Du, Xiangke. (2003) "Four-winged dinosaurs from China". "Nature", 421: pp. 335-340. 23 January 2003.
- ^ Norell, Mark, Ji, Qiang, Gao, Keqin, Yuan, Chongxi, Zhao, Yibin, Wang, Lixia. (2002). "'Modern' feathers on a non-avian dinosaur". Nature, 416: pp. 36. 7 March 2002.
- ^ Czerkas, Sylvia J. ed. (2002) "Feathered Dinosaurs and the Origin of Flight" The Dinosaur Museum Journal Volume 1. Blanding, Utah, USA. The Dinosaur Museum, August 1, 2002
- ^ Xing, X., Zhou, Z., Wang, X., Kuang, X., Zhang, F., and Du, X. (2003). "Four-winged dinosaurs from China." Nature, 421: 335–340.
- ^ Turner, Alan H.; Pol, Diego; Clarke, Julia A.; Erickson, Gregory M.; and Norell, Mark.. (2007). "A basal dromaeosaurid and size evolution preceding avian flight." Science, 317: 1378-1381. doi:10.1126/science.1144066
- Czerkas, S.A., Zhang, D., Li, J., and Li, Y. (2002). "Flying Dromaeosaurs", in Czerkas, S.J.: Feathered Dinosaurs and the Origin of Flight: The Dinosaur Museum Journal 1. Blanding: The Dinosaur Museum, 16-26
Senter, P., Barsold, R., Britt, B.B., and Burnham, D.A. (2004). "Systematics and evolution of Dromaeosauridae (Dinosauria, Theropoda)." Bulletin of the Gunma Museum of Natural History, 8: 1-20..
