Thumb-sized vertebra may be oldest dinosaur ever found in Iberia

In the Algarve region of southern Portugal, near the municipality of Loulé, a single bone no larger than a human thumb has rewritten the earliest chapter of dinosaur history on the Iberian Peninsula. The fossil—a theropod vertebra measuring 37 millimeters, or about an inch and a half—was recovered from rocks belonging to the Silves Group, sediments that paleontologists date to more than 220 million years ago, deep in the Late Triassic epoch. Labeled NOVAFCT-DCT-5562 in the scientific record, this small vertebral centrum, the central body of a back vertebra, stands as the oldest dinosaur remains ever found in the region.

Until this discovery, the Triassic fossil record of Portugal told a story of water. The rocks of this age had yielded large amphibians, phytosaurs—crocodile-like predators—placodonts, and various fish. These were the creatures that dominated the ancient Portuguese landscape, most of them tied to aquatic or semi-aquatic environments. Dinosaur footprints had been attributed to this period, but no actual bone had ever been recovered. The vertebra from near Penina changed that. It represents the first fully terrestrial vertebrate ever described from Portuguese Triassic deposits, a shift from the aquatic fauna that had defined the fossil record until now.

Identifying such a small, fragmentary specimen required careful comparative work. Researchers at Universidade Nova de Lisboa, Dr. Rui Tiago dos Santos-Matos and Dr. Octávio Mateus, examined vertebrae from many early dinosaurs and their close relatives, then conducted evolutionary analyses using an expanded dataset of thirteen new characters they developed specifically to describe the back vertebrae of early theropods. The analyses placed the Portuguese bone within neotheropods, a branch of early predatory dinosaurs, and identified it as the closest known relative of Sarcosaurus woodi, a species known from Early Jurassic rocks in England.

If this evolutionary placement holds, the implications extend far beyond Portugal. The Portuguese specimen is at least 20 million years older than Sarcosaurus, meaning the two cannot be the same species or even the same genus. More significantly, the relationship between them would push back the lineage leading to Sarcosaurus from the latest Late Triassic into the early or middle Late Triassic—a substantial extension of the known history of this dinosaur group. The bone would rank among the oldest neotheropods known anywhere in the world, not just on the peninsula.

Yet the fossil's very smallness and incompleteness impose limits on what science can claim about it. The vertebra lacks any features unique to a particular species, and the remains are too fragmentary to assign it to any known species or to justify naming a new one. The researchers concluded that NOVAFCT-DCT-5562 may represent an unknown theropod species, but the evidence cannot yet support that formal designation. What remains certain is that a small predatory dinosaur walked the Iberian landscape in the Late Triassic, and that this single bone has opened a new window onto the deep history of dinosaurs in Europe. The study was published this month in the journal Fossil Imprint, and the specimen itself is preserved in the university's collections, available for future study as techniques and comparative datasets continue to evolve.