| 论文摘要 |
A discovery has been made where thirteen footprints, two invertebrate traces and symmetrical ripple marks were found in a greyish green calcareous fine sandstone bed. The discovery was found in the Lower Cretaceous Shengjinkou Formation of Urho area, northwestern Junggar Basin, Xinjiang and it formed three trackways and four isolated tracks. Classic methods were used to study the dinosaur footprints in the Urho area, which included measuring the stratigraphic sections and the footprint parameters in the field. Similar standards of measurements were used for the measurement of footprint length and width, digit length and width, the divarication between digits, the length and width of anterior triangle, pace and stride lengths. In addition, photos of each footprint were taken and the orientation and distance between the neighboured tracks were measured. Distributions and outlines of the footprints were drawn in the computer by using CorelDRAW. On the other hand, silicone rubber demould was used for the well preserved specimens for a detailed research and from the detailed study of the footprints and trackways, two different types of theropod footprints were identified. The large three-toed footprints were a new species, named Asianopodus niui ichnosp. nov., which are large sized tridactyl (47.0–56.0？cm long and 31.0–42.0？cm wide, width/length between 0.66–0.75), the divarication between digits II and IV is 49.00°–55.34°, subsymmetrical, digit III is slightly longer than digit II, but more longer than digit IV, the length/width of anterior triangle between 0.34–0.37, V-shape tracks with a distinct bulbous heel impression, without manus and tail impressions, the phalangeal formula is 3-3-2, the pace length is between 164–180？cm, the stride length is 328–336？cm. It is significant to note that this is the largest Asianopodus footprints that have been discovered. The medium-sized tracks belong to Asianopodus pulvinicalx, which are middle sized tridactyl (21.0–27.0？cm long and 18.0–20.0 cm wide, width/length between 0.72–0.86), the divarication between digits II and IV is 46.63°–51.40°, subsymmetrical, digit III is more longer than digit II and digit IV, the length/width of anterior triangle between 0.44–0.54, V-shape tracks with a distinct bulbous heel impression and without manus and tail impressions, the phalangeal formula is 3-3-3, the pace length is between 76.5–83.2？cm, the stride length is 160？cm. According to the footprint length, pace and stride length, relative stride length of the tracks, we calculated that the body length of A. niui ichnosp. nov. is 5.89？m and the speed is 8.14？km/h, while the body length of A. pulvinicalx is 2.52？m and speed is 6.48？km/h. Based on the symmetric ripple marks and invertebrate traces on the surface of the footprints layer, we infered that both the trackmakers of the Urho dinosaur footprints walked in the shore and shallow lacustrine environment. |
