Field notebooks recently recovered from a deceased paleontologist have provided vital missing details needed by researchers to complete the study of a remarkable fossil fish discovered nearly three decades ago.
The story began in 1999 when Dr. Richard Kohler discovered the fossil during a research expedition on Pitt Island in the Chatham Islands.
While exploring the west coast of the island above Waihere Bay, Koehler noticed a three-dimensional preserved, mummified fish fossil in a steep section of rock that was almost impossible to access.
To fix this, he walked 3 km back to his residence in Flowerpot Bay to borrow a ladder. He then returned to the site and carefully carved the fossil into several large, extremely heavy blocks.
Once back in Dunedin, Kohler brought the specimen to the Geology Department of the University of Otago. Emeritus Professor Daphne Lee recalls that she and the late Professor Ivan Fordyce immediately recognized its importance.
“It was completely different from any other fish fossil known in Aotearoa, New Zealand,” says Daphne.
Notable ancient hunter identified
The fossil was painstakingly prepared by the late paleontologist Andrew Grebneff and remained in the department’s collection for many years. Ultimately, it attracted the attention of fossil fish expert Professor Mike Gottfried of Michigan State University.
Mike had previously collaborated with Ivan on several studies involving New Zealand’s fossil fishes and sharks, and they soon began investigating the unusual specimen.
Researchers determined that the 1.2-meter-long mummified fish was a tarpon, a species no longer found in New Zealand waters.
Modern tarpon are large predatory fish that typically swallow smaller fish whole. The fossil’s anatomy suggests it lived much the same way. Its long body, thick hard scales, powerful tail fin and large upward-facing mouth all point to an active predator near the top of the food chain.
Missing information delays research
Despite the fossil’s importance, researchers faced a major obstacle.
Important geological information about the exact discovery site was missing, and Richard had died several years earlier.
By the time Ivan died in November 2023, a draft scientific paper was ready. However, work on the study could not proceed because researchers lacked the detailed field information needed to properly document where and how the fossil was found.
The breakthrough came in early 2025 when one of Richard’s children, who was studying at Otago, visited the department in the hope of finding photographs of his father.
After meeting Daphne, Richard’s family decided to donate her field notebooks, including those from the original Pitt Island expedition.
“This enabled us to obtain enough specific locality information to prepare fossil record forms and scientifically catalog the fossils,” says Daphne.
New fossil species named
The full study was recently published New Zealand Journal of Geology and Geophysics.
According to the researchers, this represents the first report of a high-food-chain searching predatory bony fish from rocks of the Paleogene era (about 55 million years ago) in Aotearoa.
This name was given to the fossil Ikawaihere Kohleri In honor of Richard Kohler and the place where it was discovered. The authors also thank Heidi Lanouze and the Hokotehi Moriori Trust for approving the name.
Mike says it was a privilege to work on the “remarkable fossil”.
“It substantially expands our knowledge of the evolutionary history of tarpon, and it preserves unique and unusual features in excellent 3D detail,” he says.
“This is certainly one of the most important and impressive fossils ever recovered from Aotearoa, New Zealand.”
Daphne says she’s glad the study is finally complete.
“This is a true tribute to Richard, Ivan and Andrew. We are extremely grateful to Richard’s family for donating their notebook – we couldn’t have done it without them.”