Researcher Xu Guanghui of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences has made a breakthrough in the comprehensive study of the early evolution of whole bone fish represented by the Luoping strong fish 244 million years ago, and the results of the research were published in the American Academic Journal (PeerJ) on June 24. In the 33-page paper (with another 38 pages of attached documents), Xu Guanghui describes in detail the skeletal morphology of The Strong Fish of Luoping, reveals some evolutionaryly important evolutionary sequences of skull features in whole-bone fish, and reconstructs the most complete evolutionary tree of whole-bone fish to date.
Luoping Strong Fish Tells the story of the whole bone fish
Neofin fish are the most heterogeneous taxa in the rayfin fish suborder, consisting of three main clades: Ginglymodi (with garnet as the present representative), herring (Halecomorphi (represented by bowfin fish), and bony fish (the most diverse group of aquatic vertebrates).
The interrelationship of these three clades was one of the greatest challenges of vertebrate systematics. It is only in the last decade that morphological and molecular data have reached a consensus on the sister group relationship between reamers and herring, confirming that Holostei is a monophyletic taxon. Due to the sister group relationship between whole bone fish and true bone fish, whole bone fish play a pivotal role in the study of neofin fish and even the entire suborder of spokefin fish. However, due to inadequate research on the fossil record, the evolutionary history of whole bone fish remains obscure.
Eels, living representative taxa of the hinged fish
Image from: wikipedia
Bowfin fish, a living representative taxon of the near-herring class
The Middle Triassic Luoping biota in Yunnan is one of the highest reservoirs of Triassic marine fossils in the world, and has high scientific value in studying the recovery of marine ecosystems after the extinction of organisms at the end of the Permian. Robustichthys luopingensis, up to 40 cm long, was found in the Middle Triassic Anni (244 million years ago) marine strata of Luoping, Yunnan. It has been identified as the largest genus of whole-bone fish found worldwide in the Strata of the Middle Triassic (237-247 million years ago), and is undoubtedly of great potential value for reconstructing the ecological environment of marine vertebrates in the Triassic.
Luoping strong fish fossil
Courtesy photo: Xu Guanghui
First reported and named in 2014, the Luoping strong fish is a fossil species that has attracted much attention in the study of whole bone fish. However, unsatisfactory, because the initial fossil number is relatively sparse, some key skeletal features are unclear, resulting in the systematic taxonomic position of the Ropin strong fish in the whole bone fish has become a matter of debate. Some researchers believe it is a member of the near-herring class, but others classify it as a reamer fish.
Restoration of The Strong Fish of Luoping
In this study, Xu Guanghui compared 9 newly collected fossil specimens with previous model specimens, described in detail the skeletal morphology of Luoping strong fish, revealed a lot of new anatomical information, and clarified some key skull features controversy, such as plough bone, parasphenoid bone, premaxilla, jaw bone, scleral bone, square yoke bone, tongue and jaw bone. On the basis of detailed comparative anatomy work, the Robust Fish of Luoping was included in a large-scale branch systematic study to solve the problem of systematic classification, confirmed that the Robust Fish of Luoping was one of the earliest representative species of the order Near-Herring predicted, and reconstructed for the first time the most complete evolutionary tree of whole-bone fishes to date.
Evolutionary tree of all-bone fish, The Ropin strong fish is located at the base of the near-herring predictor fish
This study breaks through the previous use of arthial fish and herring as two separate research groups, and reconstructs for the first time the most complete evolutionary tree of all-osteobic fishes to date on the basis of 224 morphological characteristics of 60 fossil and living genera, providing a new perspective for understanding the early evolution, paleoecology and paleogeography of herring.
The research has been funded by the National Natural Science Foundation of China, the Strategic Pilot Science and Technology Project of the Chinese Academy of Sciences, the Frontier Science Key Project of the Chinese Academy of Sciences, and the Special Project for the Excavation and Repair of Paleontological Fossils.
Source: Institute of Paleovertebrate Vertebrate, Chinese Academy of Sciences