Monday, 5 March 2012

Dinosaur footprints from the Early Cretaceous of Ganzu Province, China.

The Deinonychosaurs are the group of dinosaurs most closely related to the birds. They are divided into two groups, the Dromaeosaurs (popularly known as 'Raptors') and the Troodontids, which share a common hindlimb morphology, with two digits used to support weight during locomotion, and a third supporting a large, sickle-shaped claw, which was held clear of the ground.

In a forthcoming paper in the journal Acta Paleontologica Polonica, a team of scientists led by Lida Xing of the Department of Biological Sciences at the University of Alberta describe the discovery of a group of tracks made by dinosaurs with two walking toes, in the Liujiaxia Dinosaur National Geopark in Ganzu Province, China.

Liujiaxia Dinosaur National Geopark in Ganzu Province.

The tracks are located in fine sandstone/siltstone in the Early Cretaceous Yanguoxia Formation, on the southeastern edge of the Lanzhou-Minhe Basin. The site contains six dinosaur trackways, made by dinosaurs with two walking toes, with feet measuring approximately 14.8 cm in length and 6.4 cm wide and step lengths of 35.7-37.5 cm.

One of the prints. (A) Photograph. (B) Computerized Photogrammetry image with 0.2 mm contour lines. (C) Outline drawing with 10 cm scale bar. From Xing et al. (2012).

Deinonychosaurs are thought to have been capable of considerable speed when chasing prey, but none of the Liujiaxia track-makers appears to have been moving fast when making the tracks. This has no particular significance, since no modern predator runs all, or even most, of the time. There has been an ongoing debate over whether these dinosaurs were pack or solitary hunters; again this site is somewhat ambivalent, as most of the tracks are of solitary animals, but one track apparently shows six animals moving as a group.

Turning trackway. Left, photograph. Centre, outline drawing. Right, pace angulations. Scale bar is 50 cm. From Xing et al. (2012).

It is not possible to say with confidence what the actual track-maker was. The print are within the size range of a large Troodontid or a small-to-medium sized Dromaeosaur, though Xing et al. feel that the most likely track-maker was a Dromaeosaur.

4 comments:

  1. trexlooklikeacroc5 March 2012 at 18:05

    there are not close related to birds because they are birds they are not dinosaurs they are no links between dinosaurs and birds dromaeosauridae are link with archaeoteryx a true bird with modern flight feathers and pearching bird foot and was before microraptor deinonychosaurs velociraptor .dinosaurs are link with crocodilian like spinosaurus . dromaeosauridae a flightless bird . archaeoteryx a flying bird probly a good flyer it just did not fly like modern birds its just a branch in the bird family dromaeosauridae too. microraptor i do not have brain data so do not know if it could fly good it had flight feathers i know lot of dromaoesauridae had flightless bird brain not like coelophysis dinosaurs reptile small brain . archaeoteryx had a brain of a flying bird so had the tools for flight. there are many modern animals do not look like or work like there primtive ancester .dromaeosauridae have no link with scaley armo back lizard hip carve teeth saw teeth crocodilian replacement teeth jaws for bigger prey smell like reptile 50 degree arm movement coelopyhis dinosaurs. dromaeosauridae had bird hip like archaeoteryx only link is long tail. dromaeosauridae arm movement 180 degree best coelophysis dinosaurs arm movement allosaurs 50 degree rage . argentine pearch bird foot print fossil date 210 millon years ago time when coelophysis furcula was not fuse like primtive reptile furcula. so much dinosaurs features with modern crocodilian its time science call modern crocodilian dinosaurs or call dinosaurs crocodilian .modern crocodilian are aquatic dinosaurs spinosaurus is the ancester of modern crocodilian

    ReplyDelete
    Replies
    1. learn to use correct grammar please

      Delete
  2. whoah this weblog is great i like reading your articles.
    Keep up the good work! You recognize, lots of persons are searching around for this
    information, you could help them greatly.
    My website : thermal ir camera

    ReplyDelete