Several fossil species of the early Cambrian soft-tongued snail genus have been reproduced

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Science and Technology Daily Nanjing, August 27 (Jinfeng) Recently, Pan Bing, assistant researcher of the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, and Dr. Skovsted of the Swedish Natural History Museum collaborated to carry out systematic taxonomic research on the soft tongue snail fossils collected from the early Cambrian strata of the Tainan margin of North China, and found 14 species in 10 genera, including 2 new genera and 3 new species, revealing the combined appearance of the soft tongue snail in north China during this period, and the relevant results were published in the international paleontological journal alcheringa.

The soft-tongued snail is one of the earliest symmetrical animals in geological history with mineralized shells, and flourished in the Cambrian Period more than 500 million years ago. Soft-tongue snails include two subgroups of straight-pipe snails and soft-tongue snails, both of which have a calcareous cone-shaped shell and a mouth cap, the latter of which also has a pair of curved appendages protruding from the cone shell.

"In the early Cambrian period, the soft-tongued snail was usually preserved in clastic rocks in a two-dimensional flattened state and in carbonate rocks in three dimensions. However, most of the fossils preserved in carbonate rocks are phosphorylated, and their cone shells and mouth caps are usually preserved in discrete forms, and there are few hinged specimens. Pan Bing said that this also led to the long-term system classification of the early Cambrian soft-tongue snail is more confusing.

Pan Bing said that in the study, he and other researchers found a large number of soft tongue snail fossil specimens preserved in the three-dimensional phosphate-based way in the early Cambrian Xinji Formation and Monkey Mountain Formation distributed in Shaanxi, Shanxi, Henan and Anhui through the treatment of acetate bubbles.

"More importantly, the soft tongue snail specimen found this time, as well as a large number of mouth caps. What is particularly rare is that many cone shell ends preserve the outer mold of the mouth cover, which also makes it more reliable to limit the discrete cone shell to the same type as the mouth cover. Pan Bing said that by summarizing and analyzing the stratigraphic age and paleogeographic distribution of these soft-tongued snails, it was found that they should belong to the late Cambrian period from the third to the early fourth period, and the genus and species combination was most similar to Australia on the eastern edge of Gondwana at that time, and it was also similar to Greenland on the lauren continent. This also shows that around 515 million years ago, the North China Plate may have had a relatively close paleo geographical location to Australia and Greenland.