China News Service, Beijing, July 14th (Reporter Sun Zifa) The reporter learned from the Institute of Paleontology and Paleontology of the Chinese Academy of Sciences on the 14th that the researcher Xu Guanghui of the Institute passed the latest research on the Luoping biota of Yunnan Province in East Yunnan (Qujing City) Luoping County and Luxi County, Honghe Prefecture) discovered the oldest to date, a 244 million years ago (Middle Triassic Anni period) a scavenger-type neofin fish fossil, named "small and small lying fish".

A small, leaking, lying fish positive specimen. (Photo courtesy of Xu Guanghui)

  Based on the research of small and small fishes and other related new fin fishes, Xu Guanghui established a new order of the subfamily of the fins, the leaking fishes, small Leaky fish is the oldest genus of Leychthys, representing the earliest known scavenger-type basal neofin fish. This important research achievement paper in the field of paleontological evolution has recently been published in the famous zoology journal "Linna Journal of Zoology" published by Oxford University.

  Researcher Xu Guanghui told reporters through the Internet that the Triassic period is an important period for the radiation evolution of neofin fish, and that new fin fish adapted to different ecological types have emerged: there are sturdy and sharp tip predators with hemispherical shapes. Tooth-eating A-type fish, there are also plankton-eating fish with small or toothless teeth.

The small leaky lying fish is a more complete specimen. (Photo courtesy of Xu Guanghui)

  However, the newly discovered small leaky lying fish is different from these predators. It is a scavenger-type scavenger fish. Its skull shape is very special. The skull cranial bone almost heals into a whole piece, and the front gill cover The lower part of the bone leans forward, the upper jaw is shorter, the posterior end is enlarged, the lower jaw is slender, and the anterior half of the mouth has unusually long and pointed teeth. The standard body length of the small leaky lying fish is only about 3 cm. Although small and unremarkable, it is an important part of the marine ecosystem because it can decompose the remains of other animals (such as large marine reptiles) faster than microorganisms. Calling the seabed "cleaners" is very important for the normal operation of the entire marine ecosystem.

Enlarged view of the upper and lower jaws of a small leaky lying fish. (Photo courtesy of Xu Guanghui)

  Xu Guanghui said that the genus of ichthyosaurs originated from the ancient geological kingdom of Luoping and surrounding areas. Thanks to the rich Triassic fish fossil materials in this area, he obtained the research on the evolutionary relationship and classification of neofin fish A series of breakthroughs: Rebuilding a more complete evolutionary tree of early new-finned fish for the first time in the world; proposing a new classification system of new-core and new-finned fish; Toothfish belong to the newly-established Leopardidae.

  He pointed out that the close relatives of the Lepidididae are pseudo-Pikenian fishes that were previously found in South America and Europe in the Middle and Late Triassic, and the two constitute the Lepidoptera. This study is of great significance for understanding the nutritional structure of the food web of the Triassic marine ecosystem and the evolution, classification and biogeography of early neofin fish. (Finish)