<h1>Top 10 Advances in Chinese Paleontology in 2018: Mixed Metamorphic Beasts</h1>
In the past 2018, what are the major discoveries made by Chinese paleontologists? In March 2019, the Chinese Paleontological Society announced the "Top Ten Advances in Chinese Paleontology in 2018", and the selected top ten advances reflect the internationally influential research results made in various branches of Chinese paleontology in 2018, which involve paleovertebrates, paleoanthropants, paleoecology and paleoenvironment, early life, stratigraphy and other fields. We will dedicate a special topic to introduce these ten major advances, and use popular language to popularize the achievements and achievements of Chinese paleontology in 2018.
This issue introduces the second most discovered: the Hybrid Beast
<h1>Fossils from guning city</h1>
Ningcheng County is located in the southwest of Chifeng City, Inner Mongolia, bordering Liaoning Province. In Ningcheng County, paleontologists have found a large number of fossils belonging to the Rehe biota, dating back to the Early Cretaceous period 126 million years ago.
Photo note: Ningcheng County, where fossils were found, the picture comes from the internet
Photo note: Ancient mammal fossils found in Ningcheng County, picture from the Internet
A few years ago, paleontologists found a fossil of an ancient mammal in Ningcheng County, which was very complete, divided into positive and secondary molds preserved on folio stones, and the fossil number was STM33-5. The fossil was later collected and studied by a team of paleontologists from the College of Life Sciences of Linyi University and Indiana University. The researchers scanned and reconstructed the fossils in three dimensions using high-precision CT scanning techniques to restore the morphological characteristics of each bone in it. On this basis, the research team spent three years to construct a matrix of taxonomic and morphological characteristics of early mammals, including 56 paleo-mammal taxonometry units and more than 400 morphological features, and finally established the early mammalian developmental lineage tree.
In June 2018, the research team published a paper in the prestigious scientific journal Nature entitled "An Early Cretaceous eutherian and the placental–marsupial dichotomy", in which the ancient mammal was named a hybrid.
Illustration: Skeleton reconstruction of the Hybrid Beast, picture from the network
Photo note: Bi Shundong, the leader of the research team, picture from the network
The scientific name of the Ambolestes comes from the Chinese "Yuan qi is not divided, chaos is one, and the beginning of yuan qi is also", which means that it has the mixed characteristics of true beasts and post-beasts. The model species name of the hybrid beast is Ambolestes zhoui, and the species name is dedicated to Dr. Zhou Zhonghe, academician of the Chinese Academy of Sciences and director of the Institute of Paleovertebrates and Paleoanthropology, for his significant contributions to the initiation and promotion of in-depth research on the Rehe biota.
<h1>Thief in the Cretaceous tree</h1>
By reconstructing the fossils, we have a small mammal that lives in the Cretaceous Rehe biota and looks like a mouse. The body length of the mixed-element beast is only more than 30 centimeters, and one-third of it is the long tail behind it.
Hybrid beasts have long, pointed heads with large eyes that help them see their surroundings in a lack of light or in the dark. There are different types of teeth in the mouth of the hybrid, but all of them have a pointed crown, indicating that they are carnivores.
Illustration: Three-dimensional reconstruction of the skull of the mixed element beast, picture from the network
Illustration: Skull of a mixed element beast, picture from the network
The mixed-element beast has a short neck, but its body is not thin, and its limbs are longer, with five fingers on all four limbs. The fingers of the hybrid beasts are long and flexible, and they have a strong grip, indicating that they can climb trees, and their long tails are able to maintain the balance of their bodies in motion.
Paleontologists believe that the hybrid is an arboreal animal that only occasionally comes to the surface to move, so as to be able to dodge the attacks of small carnivorous dinosaurs. The mixed element beast usually stays in the tree, feeds on various insects, and is a small thief living in the tree.
Illustration: Ecological restoration of the mixed element beast, the picture comes from the network
<h1>Change the origin of marsupials</h1>
Mammals on Earth today are divided into three broad categories: single-porous, marsupial, and placental. Single-hole species are very primitive, there are only three species, the famous platypus is single-hole, marsupial and placenta account for the vast majority of mammals, of which marsupials (represented by kangaroos and koalas) are relatively primitive, and their females have a nursery bag in their abdomen, in which immature larvae can be placed to breastfeed. When did marsupials appear and how did they evolve?
Caption: Today's marsupials, images from the web
Image note: Fossils, line diagrams and restorations of Chinese possums, picture from the Internet
In 2003, paleontologists named the Chinese possum ,a paleomata from the Rehe biota that is thought to be the earliest marsupial, and its discovery proves that marsupials originated in Asia. In the study of mixed metaphytes, paleontologists found that they and Chinese possums belong to the early true mammals (placenta), but the outer drum bone morphology is similar to the living marsupial possum possum, so it has the common characteristics of marsupials and placenta euphots. It is the study of the hybrid beast that proves that the Chinese possum is not the ancestor of marsupials, that marsupials do not appear in Asia, and that the earliest known marsupials are deltatheridiums that lived in North America 110 million years ago.
Illustration Note: Comparison of the hyoid artifact of the hybrid beast with the opossum and the cougar hyoid apparatus, the picture comes from the network
In addition to proving that marsupial origins were not Asian, paleontologists have also found for the first time in fossils of hyoid bones, which are slender bones hanging between mammalian skulls and laryngeal knots that provide attachment to the tongue and neck muscles. The hyoid bone organ is a very important structure that affects the animal's eating, chewing and vocalization, and because it is not connected to other bones, it is difficult to preserve. The discovery of the hyoid bone of the mixed element beast, which is composed of 7 bones, is very delicate, and its discovery has brought new enlightenment to the study of many fields such as biology and medicine.
The discovery of the little hybrid not only provides new evidence for us to explore the evolution of marsupials, but also preserves the earliest hyoid bone, and its discovery and research ranks second in the top ten advances in Chinese paleontology in 2018.
Resources:
Shundong Bi; Xiaoting Zheng; Xiaoli Wang; Natalie E. Cignetti; Shiling Yang; John R. Wible (2018). "An Early Cretaceous eutherian and the placental–marsupial dichotomy". Nature. 558 (7710): 390–395. Bibcode:2018Natur.558.. 390B. doi:10.1038/s41586-018-0210-3. PMID 29899454.