San Diego fossil identified as Earth’s earliest known insect

Key Points:

• A 324-million-year-old fossil, previously misidentified as a shrimp-like crustacean, has been reclassified as one of the earliest known insects, named Chosha praecursor, reshaping our understanding of insect evolution.
• The fossil, which had been stored at the San Diego Natural History Museum for 40 years, was reexamined by Cambridge PhD student Erik Tihelka, who identified key insect features such as six legs on the thorax and an egg-laying organ.
• This discovery helps fill the “hexapod gap,” a 60-million-year period in the fossil record where early insects were thought to be absent, providing insight into the transition from aquatic ancestors to terrestrial insects.
• The specimen exhibits a blend of insect and crustacean traits, including extra paddle-like legs possibly used for gliding in water, highlighting evolutionary adaptations during this critical period.
• Following the reclassification, the fossil has been moved from storage to a prominent display at the museum, symbolizing a significant scientific breakthrough and renewed public interest in prehistoric life.