The Royal Commission for AlUla (RCU) has announced the documentation and international publication of a scientific discovery of rare horseshoe crab fossils dating back approximately 465 million years, as part of a peer-reviewed study published in Gondwana Research, a leading international journal specialising in geological sciences.
This unique fossil discovery has been published globally for the first time, reinforcing AlUla’s position as a world-class center for geological and scientific research related to Earth’s history and biodiversity. The fossils were discovered in AlGharameel Nature Reserve in AlUla, adding a significant scientific dimension to the understanding of the region’s natural history, SPA reported.
The fossils date to the Middle Ordovician period, approximately 485–444 million years ago, making them among the oldest known horseshoe crab fossils worldwide. They are distinguished by their exceptionally large size compared to other specimens from the same period. All fossils were found preserved upside down, a mode of preservation not previously recorded, alongside trace fossils indicating attempts by the organisms to return to their natural position. This provides rare evidence of ancient behavioural patterns and enables their interpretation in light of contemporary biological knowledge, supporting advanced scientific research.
According to SPA, geological stratigraphic analysis indicated the recurrence of intense seasonal storms during that period, suggesting that these organisms congregated in shallow coastal environments affected by such events, which contributed to their preservation within sedimentary deposits.
These findings offer a clear picture of AlUla’s ancient coastal environment and add a new scientific perspective to understanding its geological and environmental history. They also highlight the commission’s capacity to provide accurate data that supports scientific research and innovation in the study of AlUla’s natural heritage.
The discovery also represents a previously unclassified species, investigated through two research phases in collaboration with a team led by Dr Russell Bicknell, an academic at Flinders University in Adelaide. The second phase, scheduled for the first half of 2026, will include the collection of additional samples and further study of the new species in preparation for its formal scientific classification. The fossil specimens have been preserved within RCU’s museum collections to support future research and public engagement.
The findings reflect the Royal Commission for AlUla’s commitment to advancing scientific transformation, strengthening AlUla’s position as a global destination for scientific discovery and geological research, enabling international partnerships, and developing research and educational programmes related to natural heritage.
