Chosha praecursor fossil reveals 24-legged insect ancestor

Researchers have identified a 324-million-year-old fossil that challenges the standard understanding of insect anatomy. The specimen, named Chosha praecursor, dates back to the Carboniferous period and was discovered in the Tesnus Formation in Texas.

While modern adult insects are defined by having six legs, this ancient species possessed 24 appendages: three pairs of thoracic legs and nine additional pairs located on the abdomen. Some of these posterior limbs featured paddle-like structures. This anatomical configuration suggests that early insect ancestors may have lived a semi-aquatic life, transitioning gradually between water and land rather than making a sudden leap to terrestrial environments.

The fossil had been previously misclassified as a crustacean larva and sat in a drawer at the San Diego Natural History Museum since its original discovery in 1985. It was re-examined by paleoentomologist Erik Tihelka from the University of Cambridge, who identified the specimen as a primitive insect through specialized polarized light imaging.