324 Million-Year-Old Insect Fossil Goes on Public Display
A misclassified specimen at a San Diego museum fills a critical 80-million-year gap in the early insect fossil record.
Updated on Oct. 28, 2026 in Geology
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A specimen previously misidentified as a crustacean at the San Diego Natural History Museum has been reclassified as Chosha praecursor, a 324 million-year-old insect fossil. This identification fills a critical gap in the evolutionary record for early hexapods.
Why it matters
The reclassification of this fossil provides key evidence regarding the evolution of insects between 385 and 322 million years ago. It demonstrates the importance of re-evaluating long-held museum collections to resolve major gaps in the historical fossil record.
The Chosha praecursor fossil features six walking legs, a three-section body, and two slender antennas, alongside 18 aquatic appendages. This morphology bridges the 80-million-year hexapod gap which previously left no clear fossils between 385 and 322 million years ago.
The players
San Diego Natural History Museum
A research institution housing 1.6 million artifacts that preserves and catalogs diverse paleontological specimens.
Erik Tihelka
A researcher at the University of Cambridge who specializes in paleontology and evolutionary transitions.
The details
Researcher Erik Tihelka identified the specimen by observing a drawing in a second-hand paleontology textbook and performing a microscopic examination using polarized light. The analysis revealed that the creature possessed both insect-like physical traits and specific aquatic appendages. This duality helps clarify how insects evolved before fully colonizing terrestrial environments during the Carboniferous period.
Timeline
385 to 322 million years ago: The hexapod gap period in the fossil record.
324 million years ago: The age of the Chosha praecursor fossil.
1985: The year the fossil originally arrived at the San Diego museum.
The Tech Race
This finding marks a major departure from the 80-million-year hexapod gap that has long stalled research into early insect evolution. It provides a definitive data point for scientists working to reconstruct the lineage of hexapods between 385 and 322 million years ago.
Residents and visitors in San Diego can now view the Chosha praecursor fossil on public display. It is currently being showcased as part of the Amazement in the Basement exhibit at the museum.
The takeaway
The reclassification of this 324-million-year-old fossil transforms an obscure museum item into a foundational piece of evidence for evolutionary biology. Visitors can see the specimen in person by visiting the San Diego Natural History Museum.
Further reading
Learn more about the latest discoveries in the Geology section.
Source note: This article includes information reported by KPBS.
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