A 438 million-year-old eugenics fish was discovered in Jiangxi province

2022-05-23 0 By

In a recent paper published in the Journal of Asian Earth Sciences, Shan Xianren, a master’s student at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and co-supervised by Researchers Gai Zhikun and Zhao Wenjin,The team’s latest research on silurian armorfishes has been published online.In this study, we report two new species of early eu-armorids, Qingshuiaspis Junqingi and Anjiaspis ericius, which were first discovered from the Early Tereqi Formation of silurian Landodoliocene (about 438 million years ago) in Wuning, Jiangxi province (FIG. 1).This is the first discovery of Euanodytes from the lower red layer in northwestern Jiangxi province, and represents the oldest and most primitive fossil record of euanodytes so far.Research not only further clarifying the phylogenetic relationship between armor fish really early and enrich the scientists for fish armor subclass early evolution and radiation of understanding, and for the lower Yangtze region long disputed generation anddistribution as well as Marine red layer division and age determination, true armor class and the gills of fish differentiation more time estimate provides key fossil evidence, etc.Armorfish is a kind of gnawed fish endemic to East Asia. Currently, it is only found in North China and Vietnam. It is a kind of indigenous fish with strong colors.Since ding Wenjiang found armorfish fossils in Qujing, Yunnan province in 1913, armorfish have been discovered for more than 100 years.Since liu Yuhai’s first formal description of armorfishes in 1965, armorfishes have been classified into subclass taxa.The subclass is divided into three monophyletic taxa, eu-armoriformes, polybranchiformes and South China taxa, except for the basal taxa (including the schistosomiformes, hanguliformes, and dionysiformes).The new Qingshuiaspis Junqingi from Qingshuiaspis Formation of Lower Red Formation in northwestern Jiangxi belongs to eosinidae, order Euarmoriformes. The genus name indicates that the fish was found in Qingshuiaspis Formation of Lower Red Formation of Silurian in Jiangxi province.The species name is dedicated to Wang Junqing, a paleoichthyologist of the Institute of Paleontology and Spine, to pay tribute to his important contributions to the study of Paleozoic paleofishes in China.Eosinidae, represented by eosinus, represents the most primitive group of Euarmoriformes, including Meishanaspis from northwest Zhejiang province and Jiangxialepis from Wuhan City, Hubei Province.The characteristics of the new genus are obviously different from those of the other three genera, and it is easy to distinguish them. The middle dorsal spine and middle dorsal spine are developed at the back end of the head nail of the new genus, and the head nail ornamentation is composed of uniform coarse nodules, which is obviously different from eosinus and coal mountain fish.Compared with jiang Xia fish, water fish has closed snout edge, longer horn and inner horn, and the dorsal dorsal tip is round and blunt, which is obviously different from jiang Xia fish.Anjiaspis ericius is the second true armored fish belonging to the genus Anjiaspis after The reticulated anjikun and Zhu Min (2005) discovered in Anji, Zhejiang province. The species name comes from its unique serrated head. Thick and sharp cone serrated teeth are regularly arranged on the side edge and leading edge of the head, like a hedgehog covered with sharp spines.Keep predators out of sight (Figure 3).The lateral line system of Anagiurus has been controversial for a long time. At first, it was thought that the lateral line system of Anagiurus consists of 4 longitudinal tubes penetrating the cephalic plate and 8 transverse tubes connected with them, and the longitudinal tubes and transverse tubes are interlaced into a grid. Later, this grid shaped lateral line system of Anagiurus was considered to be a misjudgment of the subcutaneous vascular plexus.The lateral line system of Anagiphus was found to have two pairs of longitudinal trunk canals (including middle dorsal canal, posterior superior orbital canal, inferior orbital canal and lateral dorsal canal) and at least two middle transverse connecting canals, which is typical of true armoriphus type lateral line system.In addition to the typical characteristics of true armoriformes, the hedgehog Anagiformes also have a series of highly specialized features, such as the droplet middle dorsal foramina, orbital foramina and lateral dorsal canal extremely close to the middle line of the cephalic nail, the cephalic nail has a wide abdominal ring, and the u-shaped middle dorsal canal extending backward.New phylogenetic results suggest that Anji is a monophyletic group between eosinidae and Chinese armoriidae, and its highly specialized body structure may represent a special evolutionary clad of Euarmoriformes (FIG. 4).In the past, the earliest fossil records of true armorfishes appeared in the silurian Landovirienian Late Treqi, such as Sinogalea pis from the Xikeng Formation in Xiushui area, Jiangxi province.The Qingshui Formation in northwestern Jiangxi province is integrated under the Xiajiaqiao Formation, which is rich in the Middle Tereqi Xiushan fauna. It is the early Tereqi of silurian Landoviriene. Therefore,The newly discovered Qingshuiaspis Junqingi and Anjiaspis ericius from the Shimizu Formation represent the oldest fossil record of true armoriformes to date (FIG. 4).Gai Zhikun et al. (2018) reported Platylomaspis Serratus from the Tataertag Formation in Tarim Basin, which represents the most primitive member of polybranchiformes. The Tataertag Formation can be compared with the Lower red Layer Rongxi Formation and Qingshui Formation in South China.This is supported by the team’s recent discovery of fossil material from a group of polybranchids from the Shimizu Formation.Recent discoveries of fish fossils suggest that the two major clades of Euarmoriformes and polybranchiformes diverged as early as the early Teretsch period.After differentiation, euarmoriformes underwent a rapid radiation evolution that lasted until the late Teretchi period, marked by the flourishing of eosinidae and Chinese armoriformes, while polybranchiformes were relatively conservative after differentiation and did not undergo the first radiation evolution until the Early Devonian (FIG. 4).The Silurian Marine red beds in Jiangxi are well exposed and widely developed mainly in the xiushui-Wuning area in the northwest of the province. The Xiakeng Formation, rich in Xiushan fauna, is located between qingshui Formation in the lower red layer and Xikeng Formation in the upper red layer.Since the 1980s, a large number of silurian armorfishes, including Sinogalea pis, Xiushuaspis and Rumporostralis, have been discovered in the Xikeng Formation of the Upper Red Layer in northwestern Jiangxi province.However, no fish fossils have been reported in the Qingshui Formation of the lower red layer in this area.Since 2003, the early vertebrate research team of institute of Vertebrate Palaeontology has carried out the field investigation of silurian strata and the field excavation of fish fossils in northwest Jiangxi. A number of rich fossil materials of ancient fish have been collected from qingshui Formation of Lower Red Layer of Silurian in Wuning area (Figure 5).They mainly include armoriidae, the most primitive multi-gill fish, and eosinidae, the most primitive true armoriidae. In addition, there are a small number of cartilaginous fish mainly based on the fin spines of Acanthopanths.These fish fossils were found for the first time from the lower red beds of the Silurian system in northwestern Jiangxi province, and are of great scientific significance for the early evolution of armoriformes and related stratigraphy.Shuyu is a key link in the evolutionary history of vertebrates. Its unique cranial structure provides key evidence for the division of anmaxillary nasohypophysial complex prior to the origin of jaws. Shuyu is considered as a missing link in the evolution of life as tiktalic, Archaeopteryx and Homo florius.However, its exact horizon and geological age are still controversial.Eosin originated from the silurian shallow-water Marine red beds in northwest Zhejiang province. The red beds were originally called Maoshan Formation. In 1997, Zhejiang Bureau of Geology and Mineral Resources abandoned the Maoshan Formation and adopted tangjiawu Formation, which was supported by some scholars at home and abroad.Although the study on this set of Marine red beds in northwest Zhejiang province began in the 1930s, due to the lack of standard fossils and reliable radioisotope dating data in this group, the exact geological age and regional stratigraphic correlation have puzzled silurian paleontologists for many years.The new discovery of the oldest true armorfishes from the Lower red Layer of Qingshui Formation in northwestern Jiangxi province provides the key fossil evidence for solving this problem.Three sets of shallow Marine facies in southern China bottom-up generation anddistribution as well as the development of red layer (Burgundy fine clastic rock), because of its color eye-catching, easy to identify, by formation paleontologists in China known as the red, the red layer and rodello red layer, its age respectively as the orchid multidimensional column, column, early, middle – late and rodello late (figure 6).Qingshui formation and Xikeng Formation in northwestern Jiangxi province belong to lower red bed and upper red bed respectively.The new progress in taxonomy and fossil records of armoriformes indicate that the eu-armoriformes in the Lower red stratigraphy consist of Eu-armoriformes and anagiformes. The eu-armoriformes belong to eosinidae, which is the most primitive monophyletic group of eu-armoriformes, and anagiformes represent a transitional group from eosinidae to Chinese armoriformes.The true armorfishes in the Xikeng Formation of the Upper Red Layer include Chinese armorfishes and schizostrophus, both of which belong to the Chinese armorfishes family, which is a monophyletic group more advanced than eosinidae and Angelfish.Therefore, the different assemblages of fish fossils in qingshui formation and Xikeng Formation represent different evolutionary stages of euaryngium, which provides a standard for the classification and comparison of the upper and lower silurian red beds in the Yangtze region of South China.Produced in zhejiang northwest tang armor fish in dock group including start fish, mountain fish and angie, previous taxonomic research according to “have” overall shape similarity tang dock in the group start fish such as armor fish really were compared with the armor fish in west pit group, and then think that tang basin and west pit group horizon, the time to late silurian orchid multidimensional column the special column.In this study, the taxonomic conclusion based on phylogenetic analysis shows that eosinus in tangjiawu Formation, Meishan fish and Qingshui in Qingshui Formation form a monophyletic group, eosinidae;Anji from Tangjiawu formation and Anji from Qingshui Formation constituted another monophyletic taxa, Anji;The two monophyletic groups mentioned above are more primitive than those in xikeng Formation of upper Red Layer.Tangjiawu Formation in northwest Zhejiang province should be classified into the lower red bed and can be compared with qingshui Formation.The age of eosinus should be revised to the early Silurian Landovliescene trechian about 4.38 years ago (Figs. 4, 6).The research work was supported by the Strategic Priority Science and Technology Special Project of CAS, the National Natural Science Foundation of China, and the Key Research Program of Frontier Science of CAS.FIG. 1. Ecological restoration of Junqing water fish (left) and Hedgehog Anji fish (right) (drawn by Yang Dinghua) FIG. 2.Fossil photos and restoration of Qingshuiaspis Junqingi (Taken by Gai Zhikun and illustrated by Feng Mingjuan) FIG. 3.Fossil photo of anji fish head and its restoration (taken by Gai Zhikun and illustrated by Feng Mingjuan) FIG. 4.FIG. 5. Field profile (top) and excavation site (bottom) of Qingshui Formation, Lower Red Layer of Silurian, Wuning, Jiangxi (Taken by Gai Zhikun) FIG. 6.Division and correlation of silurian Marine red beds in China (provided by Shan Xianren) source: Institute of Vertebrate Paleontology and Paleoanthropology