Eosinopteryx
| Eosinopteryx Temporal range: Late Jurassic, 160Ma | |
|---|---|
 | |
| Life restoration | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Theropoda |
| Clade: | Paraves |
| Genus: | †Eosinopteryx Godefroit et al., 2013 |
| Type species | |
| †Eosinopteryx brevipenna Godefroit et al., 2013 | |
Eosinopteryx is an extinct genus of paravian theropod dinosaurs known the late Jurassic period of China. It contains a single species, Eosinopteryx brevipenna.[1] Though initially classified as a troodontid,[1] a more comprehensive analysis of its relationships found it to be a paravian outside the group Eumaniraptora.[2]
E. brevipenna is known from a single fossil specimen recovered from the Tiaojishan Formation of western Liaoning Province, China, which has been dated to the late Jurassic period (Oxfordian age), about 160 million years ago.[3][4] The name Eosinopteryx is derived from the Greek eos ("daybreak" or "dawn"), the Latin Sinae ("Chinese"), and the Greek pteryx ("feather"). The specific name brevipenna (from the Latin brevis, "short", and penna, "feather") refers to the reduced plumage preserved in the type specimen, YFGP-T5197.[1]
Description
Eosinopteryx brevipenna is known from a single fossil specimen representing the nearly complete skeleton of a subadult or adult individual. The specimen is very small for a non-avialan dinosaur, measuring about 30 centimetres (12 in) long. Unlike most troodontids, the snout was very short, shorter than the diameter of the eye socket. The wings were about the same size as those of the related Anchiornis huxleyi, with the primary wing feathers being longer than the humerus (upper arm bone). An unusual arrangement of the wing bones would have prevented any flapping motion. The tail was very short compared to most troodontids and dromaeosaurids and also unlike members of those groups, the feet and toes were very slender, lacking highly curved claws for predation or climbing. Unusually, the tail of the only known fossil does not show signs of the presence of complex vaned feathers (rectrices), and the lower tarsals and feet appear to have been featherless, unlike many related species with "hind wings" on the lower legs and feet.[1]
A researcher from the University of Southampton said the discovery of Eosinopteryx suggests "that the origin of flight was much more complex than previously thought".[5]
References
- ↑ 1.0 1.1 1.2 1.3 Godefroit, P.; Demuynck, H.; Dyke, G.; Hu, D.; Escuillié, F. O.; Claeys, P. (2013). "Reduced plumage and flight ability of a new Jurassic paravian theropod from China". Nature Communications 4: 1394. doi:10.1038/ncomms2389. PMID 23340434.
- ↑ Pascal Godefroit, Andrea Cau, Hu Dong-Yu, François Escuillié, Wu Wenhao and Gareth Dyke (2013). "A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds". Nature. in press. doi:10.1038/nature12168.
- ↑ Hu, D.; Hou, L.; Zhang, L. & Xu, X. (2009). "A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus". Nature 461 (7264): 640–643. Bibcode:2009Natur.461..640H. doi:10.1038/nature08322. PMID 19794491.
- ↑ Liu Y.-Q.; Kuang H.-W.; Jiang X.-J.; Peng N.; Xu H.; Sun H.-Y. (2012). "Timing of the earliest known feathered dinosaurs and transitional pterosaurs older than the Jehol Biota". Palaeogeography, Palaeoclimatology, Palaeoecology. 323–325: 1–12. doi:10.1016/j.palaeo.2012.01.017.
- ↑ "Feathered dinosaur puts theory in doubt". 3 News NZ. January 25, 2013.