A 324 million-year-old insect fossil points to a gradual amphibious move onto land
A newly identified insect fossil from Texas, dated to roughly 324 million years ago, suggests early insects did not move from water to land in one abrupt jump but passed through a long amphibious phase first. According to a Nature paper reported by ScienceDaily, the new species, Chosha praecursor, carries gill-like abdominal appendages that mark that transitional stage.
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Fossil discovery in Texas
An international team including Chenyang Cai of the Nanjing Institute of Geology and Paleontology and Erik Tihelka of the University of Cambridge recovered the insect fossil from the Tesnus Formation in the Marathon Uplift of western Texas. The fossils were found in calcareous claystone concretions that preserve fine anatomical details of the creature. Researchers utilized cross-polarized light imaging to closely examine the specimen, according to a report by ScienceDaily citing the Chinese Academy of Sciences.[2]
Amphibious transition
The specimen, named Chosha praecursor, is dated to the late Mississippian sub-period, making it roughly 324 million years old. It is classified as a wingless stem-insect. The fossil clearly shows paddle-like abdominal appendages, which indicate that the insect retained features inherited from its aquatic ancestors well after early insects began their transition to moving onto land. This finding supports the idea that the move to a terrestrial lifestyle involved a long amphibious phase rather than a sudden shift.[2], [1]
Need for more evidence
The detailed findings were published as a peer-reviewed paper in the journal Nature on August 26. The research team involved a joint-training doctoral student at the University of Cambridge alongside colleagues from the United States, Spain, and other countries. The authors of the Nature study caution that their interpretation currently rests on this single fossil specimen of Chosha praecursor. Confirming exactly how widespread this gradual amphibious phase was among early insects will require additional fossil discoveries from the same transitional time window.[1], [2]
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