Lost Notebooks Solve 25-Year Mystery of Ancient Fish

When Richard Köhler's children donated his field notebooks to researchers earlier this year, they unlocked a scientific mystery that had waited nearly three decades to be solved.

Back in 1999, Dr. Köhler spotted something extraordinary on a remote cliff face above Waihere Bay on Pitt Island, New Zealand. Jutting from the rock was a perfectly preserved fish fossil, mummified in three dimensions and completely unlike anything found in New Zealand waters before.

Getting to it wasn't easy. Köhler walked three kilometers back to his accommodation to borrow a ladder, then returned to carefully extract the fossil in several massive, heavy blocks. He hauled his discovery back to the University of Otago, where professors immediately recognized something special.

The 1.2-meter fossil was a tarpon, a powerful predator with thick scales, a strong tail fin, and a large upward-facing mouth built for swallowing prey whole. At 55 million years old, it became the first Paleogene bony fish ever found in New Zealand, a pursuit predator that once ruled near the top of the food chain.

But there was a problem. Köhler had passed away years earlier, taking crucial details about the fossil's exact location with him. Without that information, researchers couldn't complete the scientific cataloging needed to publish their findings. The research paper sat unfinished for years.

Then in early 2025, one of Köhler's children, studying at Otago, visited the geology department looking for photographs of his father. After meeting Professor Daphne Lee, the family decided to donate Richard's field notebooks, including detailed records from his Pitt Island expedition.

Why This Inspires

Those worn notebooks contained exactly what scientists needed. The specific location data allowed the team to properly catalog the fossil and finally publish their research in the New Zealand Journal of Geology and Geophysics this month.

The fossil now bears the name Ikawaihere koehleri, honoring both Köhler and the place where his discovery was made. Professor Mike Gottfried, who helped identify the specimen, calls it "among the most important and impressive fossils recovered to date" from New Zealand, with unique features preserved in exquisite detail.

Lee says publishing the paper brought closure to a long journey. "It is a fitting tribute to Richard, Ewan, and Andrew," she notes, referring to colleagues who worked on the fossil but didn't live to see its publication. "We're extremely grateful to Richard's family for donating his notebooks. We could not have done this without them."

A fossil found with determination, preserved with care, and finally understood through a family's generosity now takes its rightful place in scientific history.