In a groundbreaking geological discovery, the Royal Commission for AlUla (RCU) has announced the discovery of rare horseshoe crab fossils dating back approximately 465 million years old.
The discovery has been formally documented and published in Gondwana Research international scientific journal, as part of a peer-reviewed study, according to the Saudi Press Agency (SPA).
Rare Fossils
Published for the first time worldwide, the scientific discovery solidifies AlUla’s status as an international hub for geological and scientific research into Earth’s history and biodiversity. It also adds a significant scientific dimension to the understanding of AlUla’s natural history.
The fossils, discovered in the Al-Gharameel Nature Reserve, date to the Middle Ordovician period, approximately 485–444 million years ago, ranking them among the world’s most ancient horseshoe crab ever discovered.
Moreover, they have exceptionally large size compared to other species from the same period. Interestingly, all the fossils were found preserved in an upside-down position, a pattern of preservation never before recorded, alongside trace fossils representing the creatures’ attempts to right themselves.
As part of the efforts to further strengthen #AlUla’s position as a leading global destination for geological research, @RCU_SA has announced the discovery of rare horseshoe crab fossils estimated to be approximately 465 million years old. The discovery has been formally… pic.twitter.com/aoMpWl2yhM
— الهيئة الملكية لمحافظة العلا (@RCU_SA) January 8, 2026
This discovery underscores how documenting the behaviors of ancient organisms can be integrated into modern biology to support advanced scientific research.
By studying the rock layers, researchers found evidence of frequent, powerful ancient storms, suggesting that these creatures gathered in shallow coastal waters and were caught in these storms, which quickly buried and preserved them in the sediment.
Understanding AlUla Geology
These findings confirm that ancient AlUla was once a coastal region, providing a significant breakthrough in the understanding of its geological and environmental past. Furthermore, the discovery highlights the RCU’s commitment to delivering high-level data that drives global scientific innovation and research.
Importantly, the RCU is working with Flinders University to officially classify the newly discovered fossil species in early 2026. This partnership underscores AlUla’s emergence as a world-class center for scientific research, supporting Saudi Vision 2030 objectives by promoting scientific innovation and expanding the Kingdom’s cultural and knowledge-based footprint.
