Together with the phylum Phylloscopus, the Phylum, the Phylum nematodes, the Phylum linearoids, the Phylum of clawed animals, the Phylum Tachyploids, the Phylum Tachymbrannosaurus and the Phylum of arthropods, constitute the largest branch of the animal kingdom, namely molts. The Phylum Is a relatively small benthic creature that has lived in the ocean all its life, with about 240 living species, and to date, there is no fossil record, and its origin and evolution have remained a mystery.
Recently, a joint research team composed of Zhang Huaqiao, associate researcher of the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, Xiao Shuhai, professor of Virginia Tech, and Liu Yunhuan, professor of Chang'an University, found new animal fossils preserved by three-dimensional phosphate in the early Cambrian (535 million years ago) formation in northern Sichuan and southern Shaanxi. These new fossils are early anaphyllums and represent the only known fossil record of the phylum throughout geological history. One of them is named the rare archaeopteryx (Eokinorhynchus rarus), whose name indicates its scarcity and relationship with live-kissing animals. It is about 2 mm long and has 20 solitums, each of which is covered with a circle (about 20–40) rectangular small bone plates, with five pairs of larger spiny plates symmetrically distributed, and a single large bone plate on the abdomen, each spanning 2–3 solitums, with more hollow spines randomly distributed over the body segments.
Archaeopteryx is morphologically similar to that of living animals, indicating a close evolutionary relationship between them. For example, both Archaeopteryx and living animals have hollow spines on their torsos, a small number and wide number of body segments, and bone plates on the body segments. There are also large differences between them, for example, the living animals have only 11 solitary segments and have smaller spines, while the Archaeopteryx has 20 solitary segments, and the bone plates and spines are larger. Therefore, the study believes that Archaeopteryx belongs to the ancestral type of the phylum of the phylum, and is the first fossil species of this phyla. At the same time, it also shows that the phylum of animals has appeared in the early Cambrian period, adding a new animal phylum to the "Cambrian explosion".
The findings were published Nov. 26 in Nature's sub-journal Scientific Reports.
论文相关信息：Huaqiao Zhang, Shuhai Xiao, Yunhuan Liu, Xunlai Yuan, Bin Wan, A. D. Muscente, Tiequan Shao, Hao Gong & Guohua Cao, 2015. Armored kinorhynch-like scalidophoran animals from the early Cambrian. Scientific Reports. Doi: 10.1038/srep16521.
Restoration of archaeopteryx
Archaeopteryx snout insect scanning electron microscope photos
Source: Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences