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closeFlight of Juvenile Dromaeosaurids needs more evidence (Response to Parsons & Parsons)
Posted by YunCG on 17 Apr 2015 at 11:08 GMT
Parsons and Parsons compared juvenile Deinonychus specimen with adult individuals and concluded that since juvenile Deinonychus have small body size and skeletal characters and proportions are more similar to volant dromaeosaurids like Microraptor or Changyuraptor, they were likely to had flight. Though Parsons and Parsons made a first detailed ontogeny of dromaeosaurids here and it is quite likely that juvenile Deinonychus had lived in trees [1], the hypothesis that "Flightless dromaeosaurid juveniles were able to flight" needs more evidence.
It is sure that skeletal charaters and proportions contribute greatly to flight ability, but feather structures play a major role in flight [2]. Though it is very likely that Deinonychus had feathers, too, but currently nothing is known about Deinonychus remige lengths, structures or numbers. Therefore, to inference about its flight ability, more evidences of its feathers are necessary.
[1] Parsons, W.; Parsons, K. (2006). "Morphology and size of an adult specimen of Deinonychus antirrhopus, (Saurischia, Theropoda)". Journal of Vertebrate Paleontology 26 (3 sup.): 109A.
[2] Gang Han, Luis M. Chiappe, Shu-An Ji, Michael Habib, Alan H. Turner, Anusuya Chinsamy, Xueling Liu & Lizhuo Han (15 July 2014). "A new raptorial dinosaur with exceptionally long feathering provides insights into dromaeosaurid flight performance". Nature Communications. 5, Article number: 4382
RE: Flight of Juvenile Dromaeosaurids needs more evidence (Response to Parsons & Parsons)
bparsons replied to YunCG on 17 Apr 2015 at 23:57 GMT
Obviously, fossil feathers from Deinonychus would greatly strengthen our contention, but given the exaggerated size of the manual region of these juvenile forelimbs, our functional interpretation of the features we have examined appear, in our opinion to be reasonable. Currently, we are examining further osteological evidence for the biomechanics of dromaeosaurid flight that might strengthen our initial observation, but there is no denying that such a claim will continue to be contentious at best until if and/or when the feathers of Deinonychus, from specimens representing both juvenile and adult representatives of the ontogeny of that taxon, have been recovered and described. From the perspective of just such further field discoveries, our current field research has one of the better chances of turning up just such material, but unfortunately, to this date, nothing of that nature has been uncovered. So, currently your point of criticism is quite valid. Our best response to it is that we will continue to strive to discover further evidence that might support our argument from our ongoing efforts in the field. We thank you for your interest in our work.