On June 26, a team of Chinese and foreign paleontologists announced that they had discovered a batch of well-preserved dinosaur footprints in Fushun, Zigong, Sichuan Province, including a tiny dinosaur footprint of only 10.2 millimeters long, the smallest dinosaur footprint currently recorded in China.
[These "chicken feet" are not dinosaur footprints]
How were these dinosaur footprints discovered?
This has to start in July 1998. Ding Yongfu and Ding Yongjian, villagers of Wuli Village, Yongnian Town, Fushun County, decided to use the open space next to their houses to dig a pond to store water in order to solve the problem of daily washing and laundry water at home. Because the surface of the loose pile is full of hard yellow-gray sandstone, the Ding brothers spread the long strips of stone they had mined around the pond for everyone to walk. Although people sometimes notice that some rock surfaces are covered with "chicken feet" shapes during walking, people don't think much about it.
In April 2017, Ding Yongfu's daughter Ding Li posted several photos of stepping stones next to the pond online and asked if the "chicken feet" on the photos were dinosaur footprints. After learning of this news, the Zigong Dinosaur Museum went to the field in early May 2017 to check and confirmed that it was a dinosaur footprint. In mid-May, after consultation with the other party, the Zigong Dinosaur Museum collected these dinosaur footprint fossils back to the museum and conducted research.
[The Tracer is roughly equivalent to the modern sparrow]
The Zigong Dinosaur Museum collected eight footprint plates, of which a very small footprint on the Fifth rock slab has attracted the attention of scholars. The No. 5 slab is about 0.35 square meters and has at least 44 three-toed footprints on it. One of the footprints is 10.2 mm long and 9.6 mm wide, with three distinct toes, the third toe being the most prominent, without a clear toe pad, and a relatively blunt paw print on each toe. This footprint is currently the smallest dinosaur footprint recorded in China.
Fossil slabs courtesy of interviewees
Compared with this small footprint, the other footprints on the rock slab are larger, and the length is between 2.2 and 6.2 centimeters. Morphologically, these footprints can be classified as stilt-footed dragon footprints. The common size of the stilt-footed dragon footprint is less than 15 centimeters, and some very small saw-footed dragon footprints have been found in many parts of the world before. For example, the footprints of Emei Stilt-legged dragons in the Emei Cretaceous system in Sichuan were once considered to be one of the smallest dinosaur footprints in China, and their best-preserved footprints contain paw prints of 27 mm.
As for whether the Fushun specimen was left by a newborn baby dinosaur or by an adult small dinosaur, the jury is still inconclusive. A series of footprints of varying sizes but relatively uniform morphology are preserved on the slabs, possibly representing a collection of footprints of small theropod dinosaurs at different stages of development. Therefore, scholars tend to believe that the tiny footprints of Fushun were left by small dinosaurs that had just been born, and the size of their footprint makers is estimated to be about 12 centimeters long, roughly equivalent to modern sparrows.
[Revealing the early or very early emergence of theropod dinosaurs]
If the Fushun tiny footprint does record the footprints left by juvenile theropod dinosaurs early in life, it is likely to indicate a developmental strategy of early or ultra-early growth. Early or ultra-early adulthood is one of the ancient features of the main plesiosaurs, which have appeared in some dinosaurs (e.g., diplodonts, anti-birds) and other vertebrates (e.g., pterosaurs). Among living animals, some early or ultra-early adult animals, such as most land birds and game birds, when they hatch from the egg shell, their eyes are open, the whole body has dense fluff, the legs are strong, and they can follow the parent birds to feed within a day or even a few hours.
Micro Small Footprint Interview subjects provide
After a survey of the outcrops of the surrounding rock formations, scholars believe that the fossil production layer of the footprint is the Lower Jurassic artesian well formation. The footprint combination found in Zigong Fushun expanded the dinosaur fossil record in the lower Jurassic strata of the region, which is also the first record of micro-small theropod dinosaur footprints during the Zigong Jurassic period, revealing the early or very early formation of theropod dinosaurs, and the possibility of the existence of tiny adult tracers.
A large number of stilt-footed dinosaur footprints indicate the high abundance of local theropod dinosaurs at that time, and these theropod dinosaurs were confirmed to be widely distributed in the Sichuan Basin in the early Jurassic Period, which was of great significance for the restoration of the paleoecology, paleogeography and paleoenvironment of the region.
Participating units include the Zigong Dinosaur Museum, China University of Geosciences (Beijing), Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, University of Colorado, German Museum of Paleontological and Amphibians, and College of Charleston. The paper was published in the journal Historical Biology.
Column Editor-in-Chief: Huang Haihua Text Editor: Huang Haihua Title Image Source: Tiny Footprints and Dimes. Courtesy of interviewees
Source: Author: Huang Haihua