Sometimes the most remarkable discoveries come from the smallest clues. In the heat of a Montana summer, a fossil the size of a fingertip opened a window into a branch of crocodile history that no one had seen before.
This find, uncovered by a keen-eyed undergraduate student, revealed a species that reshaped ideas about crocodyliform evolution in North America.
The discovery is more than a tale of bones. It highlights the role of curiosity, persistence, and student-led science in piecing together Earth’s deep past. It also shows that even tiny fragments of past life can illuminate the vast, complex story of evolution.
Tiny crocodile fossil discovered
About 95 million years ago, a juvenile crocodyliform nicknamed Elton lived near the Western Interior Seaway. The animal measured no more than 2 feet (60 centimeters) long, about the size of a large lizard.
Montana State University paleontology professor David Varricchio explained that even as an adult, Elton would not have exceeded 3 feet (90 centimeters). This makes Elton far smaller than most of its relatives.
Unlike most members of the Neosuchia clade, which includes modern crocodilians and their ancestors, Elton was adapted to life on land. With its specialized teeth, it likely ate plants, insects, and small animals.
This unusual anatomy placed it within a previously unknown family of crocodyliforms that was unique to the Cretaceous of North America.
Fossil with a strange texture
Harrison Allen, then an undergraduate in Varricchio’s field course, noticed something odd while digging in Montana’s Blackleaf Formation in 2021. The fossil fragment he picked up had a strange texture.
“I brought it to Dr. Varricchio and knew it must be something good, because he said, ‘Take me to where you found this,’” Allen recalled.
That moment changed Allen’s path. He is now a doctoral student at Stony Brook University and lead author of a new study that describes Elton’s remains.
Fossil reveals new crocodile
The team named the animal Thikarisuchus xenodentes, meaning “strange, sheathed teeth.”
The discovery revealed new details about Blackleaf’s paleoecology and the evolutionary story of crocodyliforms.
Allen remembered the excitement of unearthing the specimen. “After the dig, Dr. Varricchio told me why he was so excited the day I found the initial specimen. It had so much visible anatomy to explore, and he could see it was a tiny, tiny croc skull, fully articulated and preserved – it was a special thing.”
From fragments to science
Back in the lab, Allen and fellow student Dane Johnson sifted through bags of sediment, finding dozens of fragile bones. Listening to Elton John’s “Crocodile Rock,” they nicknamed the fossil Elton, long before it received its scientific name.
Because the fragments were delicate, the team relied on CT scans to reconstruct the skeleton digitally. Allen spent more than 100 hours separating bone from rock, slice by slice.
“Harrison worked super hard to digitally reconstruct the animal, and it came out beautifully,” said Varricchio.
Fossils show crocodile family
The team’s analysis suggested that Thikarisuchus may have been preserved in a burrow, similar to other fossils found in the region. Its anatomy placed it in a newly recognized family, Wannchampsidae, which shared traits with a Eurasian group called Atopasauridae.
“It suggests that during the same time period, we’re seeing convergent evolution between two distantly related groups due to similar environmental conditions, prey availability and who-knows-what that prompted crocs on opposite sides of the planet to develop similar features,” Allen said.
A broader picture
Finds like Elton are rare, but they remind scientists that crocodyliforms once explored an astonishing variety of lifestyles.
Some swam in open oceans, others ambled across dry land, and a few may even have munched on plants. Elton’s place in this spectrum is particularly exciting because it pushes the known diversity of North American crocs in new directions.
The Blackleaf ecosystem itself adds depth to the story. Known for yielding dinosaur remains, it has now produced one of the smallest crocodyliforms on record. Its sediments preserve snapshots of ancient environments where land and sea were in constant conversation, shaping species in unexpected ways.
Tiny crocodile fossil with a big legacy
For Allen, Elton was the perfect undergraduate project. The find drew him deeper into crocodyliform research, expanding his interest to species across the globe.
“The majority of diversity of crocodyliforms is in the past. There were fully marine crocs, fully terrestrial crocs, herbivorous crocs, omnivores and some that cracked shells,” he said. “That amazed me and made me want to get into this more specific realm of paleontology.”
Varricchio praised Allen’s dedication. “It was a true pleasure to have Harrison as a student here – so much positive enthusiasm, followed up with great research,” he said.
The fingertip-sized fossil that first caught Allen’s attention turned into a scientific story spanning millions of years, linking Montana’s rocky formations to global patterns of evolution. Elton may have been small, but its legacy looms large in paleontology.
The study is published in the Journal of Vertebrate Paleontology.
Image credit: Artists rendering of Thikarisuchus xenodentes – Dane Johnson/Museum of the Rockies
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