New Dinosaur Species Solves Century-Old Mystery

Tiny Jurassic Runner Unearthed in North America

A remarkably complete fossil of a small, swift dinosaur from the Jurassic period has shed light on a long-standing scientific enigma. Discovered in the famed Morrison Formation of the western United States, this new species, *Enigmacursor mollyborthwickae*, is helping paleontologists re-evaluate previous assumptions about dinosaur diversity.

Unlocking a Taxonomic Puzzle

For over a hundred years, scientists have grappled with classifying certain small herbivores found in the Morrison Formation, a region more famous for its colossal predators like *Allosaurus* and giant plant-eaters such as *Stegosaurus*. The discovery and official description of *Enigmacursor mollyborthwickae* represent the most complete specimen of its kind, finally providing the key to breaking down this complex taxonomic puzzle.

The fossil was found in a region that has been extensively studied, yet it highlights how smaller creatures have often been overlooked. Researchers believe this find is likely the first of many small dinosaurs still waiting to be discovered in the western United States.

Focus Shifts to Smaller Finds

Professor Susannah Maidment, a leading dinosaur expert and the study’s principal author, emphasized that much of the past research in the Morrison Formation concentrated on identifying the largest and most spectacular dinosaur specimens. She noted that smaller dinosaurs frequently received less scientific attention, potentially remaining hidden in the fossil record.

“Although Morrison’s formation has been known for a long time, most of the focus is looking for the biggest and most impressive dinosaurs,”

—Professor Susannah Maidment

Professor Maidment added that these smaller species could still be waiting underground. The unveiling of *Enigmacursor* suggests that significant discoveries can still be made even in well-explored areas, challenging long-held scientific assumptions about dinosaur populations.

The study detailing this significant find, titled “Enigmacursor mollyborthwickae, a neornithischian dinosaur from the Upper Jurassic Morrison Formation of the western USA”, was published in the journal *Royal Society Open Science*. Its authors include Professor Susannah Maidment and Paul M. Barrett.

Broader Implications for Paleontology

The discovery of *Enigmacursor* also serves as a reminder that the fossil record is constantly being updated, revealing new insights into prehistoric ecosystems. For instance, the discovery of juvenile *T. rex* fossils containing smaller dinosaur remains has helped scientists understand dietary shifts in young predatory dinosaurs. This points to how even seemingly minor fossil finds can contribute to a more comprehensive understanding of ancient life.