Caudipteryx

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Caudipteryx
Caudipteryx zoui fossil cast in the Hong Kong Science Museum.

Caudipteryx zoui fossil cast in the Hong Kong Science Museum .

Temporal occurrence
Lower Cretaceous (late Barremian to early Aptian )
129.4 to 123 million years
Locations
Systematics
Theropoda
Coelurosauria
Maniraptora
Oviraptorosauria
Caudipteridae
Caudipteryx
Scientific name
Caudipteryx
Ji , Currie , Norell & Ji , 1998
Art
  • Caudipteryx zoui
  • Caudipteryx dongi ( Zhou & Wang, 2000 )

Caudipteryx was a feathered theropod dinosaur from the group of Oviraptorosauria from the Lower Cretaceous Liaonings ( People's Republic of China ). Two species of this genus areknown, Caudipteryx zoui and Caudipteryx dongi . They were small, bird-like animals with an almost edentulous beak, arms, and a short tail that ended in a fan of feathers.

Finds and naming

Caudipteryx was 1998 by Ji, Currie, Norell and Ji based on two partial skeletons firstdescribed ( holotype ; catalog number NGMC 97-4-A and para-type; catalog number NGMC 97-9-A). A third fossil (catalog number IVPP 1240) was first described by Zhou and Wang in 2000 as Caudipteryx dongi . Caudipteryx zoui means something like "Zou's tail feather", the epithet zoui honoring the Chinese Vice Prime Minister Zou Jiahua , who supports the scientific work in Liaoning. The Artepiteth of the second species Caudipteryx dongi honors the Chinese dinosaur expert Zhiming Dong .

The finds come from the Yixian Formation , a rock formation belonging to the Jehol Group , and are dated to the late Barremian to early Aptian .

features

Skeleton assembly of a Caudipteryx zoui in the Museum am Löwentor , Stuttgart
Caudipteryx zoui

Like many other maniraptors , Caudipteryx displayed an interesting mix of reptilian and bird-like traits. The skull was box-shaped and shorter than the thighbone (femur) because the anterior orbital region of the skull (in front of the eyes) was shortened. The elliptical nostrils were larger than the antorbital window - a feature of modern birds. The jaws were shaped into a beak that showed only four teeth on each intermaxillary bone (premaxillary) at the front end of the upper jaw. The tooth crowns were needle-like, with the tooth roots five times wider than the visible part of the teeth.

Caudipteryx in size comparison with a human

Caudipteryx had 12 cervical vertebrae, 9 dorsal vertebrae and 22 caudal vertebrae. The ribs have hooked processes, another characteristic of birds. The tail was short and only a quarter of the body length. The arms were slender and the hand showed 3 metacarpal bones , with the first metacarpal bone only 40% as long as the second. The third finger was reduced and showed only two phalanges, the claw (ungual) missing. The acetabulum was large and made up almost a quarter of the length of the ilium - in birds, the acetabulum was only 11% of the length of the ilium. The hind legs were thin and more than twice as long as the arms, with the metatarsal bones elongated.

The tail and wing feathers have been handed down as fossil prints. The wing feathers were between 15 and 20 centimeters long and formed a wing-like fan along the second finger. The holotype shows eleven long tail feathers on the left side of the tail, which were probably paired with another eleven feathers on the other side of the tail. The feathers, like the contour and flight feathers of modern birds, consisted of a spindle, a feather shaft and a feather flag made of interlocking rays and hooks. In contrast to the arm wings of Archeopteryx and more modern airworthy birds, the wing feathers of Caudipteryx show no asymmetry.

Paleobiology

Because of the largely toothless beak, Caudipteryx and other oviraptorosaurs are believed to be omnivores . Gastroliths were found in two specimens (NGMC 97 4 A and NGMC 97 9 A) - stones that the animals swallowed to break up food in the gizzard. These are rounded, polished pebbles in the stomach region of the specimens that are up to 4.5 mm in diameter.

Systematics

Live reconstruction of Caudipteryx zoui

Since it was first described by Ji et al. in 1998, the systematic affiliation of Caudipteryx became controversial. Since the fossils show clear imprints of feathers and several cladistic analyzes came to the conclusion that it was a non-avian theropod from the group of Oviraptorosauria, it was at least at the time of the first description the clearest indication of an ancestry of the birds from the dinosaurs. The paleontologist Lawrence Witmer says: "The presence of unambiguous feathers in an unambiguously nonavian theropod has the rhetorical impact of an atomic bomb, rendering any doubt about the theropod relationships of birds ludicrous" (in German something like: "The presence of unambiguous feathers in one unambiguous non-bird theropod has the rhetorical impact of an atomic bomb, which makes any doubt about the relationship of the theropods with birds appear ridiculous ”).

Caudipteryx zoui fossil in the Hong Kong Science Museum

Other paleontologists disagree with this consensus. Jones et al. (2000) based on mathematical comparisons of the body proportions of flightless birds and theropods that Caudipteryx was a flightless bird and a descendant of flightless ancestors. However, Dyke and Norell (2005) questioned this finding, pointing to errors in the mathematical methods, and using their own analysis to conclude that Caudipteryx was indeed a non-avian theropod. The view that not only Caudipteryx was a dinosaur-like flightless bird, but also the entire group of Oviraptorosaurier and Deinonychosaurier the descendants of earlier (already airworthy) ancient birds were and therefore even belonged to the group of birds that will, among other things Feduccia et al. (2005). These researchers believe that the birds are not descended from theropods, but from earlier archosaurs . Osmólska et al. (2004) also came to the conclusion that the Oviraptorosauria including Caudipteryx must be classified within the birds. In contrast to Feduccia, however, they believe that the birds, and therefore the Oviraptorosauria, were descendants of more primitive theropods.

Caudipteryx is considered to be a basal (primeval) representative of the Oviraptorosauria. With the first description of the species Caudipteryx dongi in 2000, Zhou and Wang established a new family , the Caudipteridae, which should only contain the genus Caudipteryx with the two species. However, there was no definition of this new taxon , and since the family contains only one genus, i.e. is monotypical , it is viewed by many researchers as redundant and not accepted. In 2008, He et al. however, the new genus Similicaudipteryx and classified them within the Caudipteridae.

Individual evidence

  1. ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 149, online ( memento of the original from July 13, 2015 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / press.princeton.edu
  2. a b c Zhong-He Zhou , Xiao-Lin Wang: A new species of Caudipteryx from the Yixian Formation of Liaoning, northeast China. In: Vertebrata Palasiatica. Vol. 38, No. 2, 2000, ZDB -ID 2485763-4 , pp. 113-130, digitized version (PDF; 1.83 MB) .
  3. a b c d e Ji Qiang, Philip J. Currie , Mark A. Norell , Ji Shu-An: Two feathered dinosaurs from northeastern China. In: Nature . Vol. 393, No. 6687, 1998, pp. 753-761, doi : 10.1038 / 31635 .
  4. a b c Halszka Osmólska , Philip J. Currie , Rinchen Barsbold : Oviraptorosauria. In: David B. Weishampel , Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 165-183, here p. 181.
  5. ^ A b Lawrence M. Witmer : The Debate on Avian Ancestry; Phylogeny, Function and Fossils. In: Luis M. Chiappe , Lawrence M. Witmer (Eds.): Mesozoic Birds. Above the Heads of Dinosaurs. University of California Press, Berkeley CA et al. 2002, ISBN 0-520-20094-2 , pp. 3-30.
  6. Zhonghe Zhou, Lianhai Hou: The Discovery and Study of Mesozoic Birds in China. In: Luis M. Chiappe, Lawrence M. Witmer (Eds.): Mesozoic Birds. Above the Heads of Dinosaurs. University of California Press, Berkeley CA et al. 2002, ISBN 0-520-20094-2 , pp. 160-183.
  7. David E. Fastovsky , David B. Weishampel: The Evolution and Extinction of the Dinosaurs. 2nd edition. Cambridge University Press, Cambridge et al. 2005, ISBN 0-521-81172-4 , pp. 319-322.
  8. Terry D. Jones, James O. Farlow, John A. Ruben, Donald M. Henderson, Willem J. Hillenius: Cursoriality in bipedal archosaurs. Vol. 406, No. 6797, 2000, pp. 716-718, doi : 10.1038 / 35021041 .
  9. ^ Gareth J. Dyke , Mark A. Norell: Caudipteryx as a non-avialan theropod rather than a flightless bird. In: Acta Palaeontologica Polonica. Vol. 50, No. 1, 2005, ISSN  0567-7920 , pp. 101-116, digitized version (PDF; 370.47 kB) .
  10. Alan Feduccia , Theagarten lingham-Soliar, J. Richard Hinchliffe: Do feathered dinosaurs exist? Testing the hypothesis on neontological and paleontological evidence. In: Journal of Morphology. Vol. 266, No. 2, 2005, ISSN  0362-2525 , pp. 125-166, doi : 10.1002 / jmor.10382 .
  11. Paul C. Sereno , Steve McAllister, Stephen L. Brusatte: TaxonSearch: a relational database for supAGENeric taxa and phylogenetic definitions. In: PhyloInformatics. No. 8, 2005, ZDB -ID 2197019-1 , pp. 1–21, online (PDF; 1.5 MB) ( Memento of the original from August 20, 2007 in the Internet Archive ) Info: The archive link was automatically inserted and still Not checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / systbio.org
  12. Tao He, Xiao-Lin Wang, Zhong-He Zhou : A new genus and species of caudipterid dinosaur from the Lower Cretaceous Jiufotang Formation of western Liaoning, China. In: Vertebrata PalAsiatica. Vol. 46, No. 3, 2008, ISSN  1000-3118 , pp. 178–189, digitized version (PDF; 1.82 MB) ( memento of the original from March 3, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / www.ivpp.cas.cn

Web links

Commons : Caudipteryx  - collection of images, videos and audio files