RIYADH, Jan. 9 (Xinhua) — The Saudi Royal Commission for AlUla announced on Thursday the discovery of horseshoe crab fossils dating back approximately 465 million years.
The discovery was included in a peer-reviewed study published in Gondwana Research, a leading international journal specializing in geological sciences, the Saudi Press Agency reported.
The fossils, discovered in the AlGharameel Nature Reserve in AlUla, located in northwest Saudi Arabia, date back to the Ordovician period, approximately 485-444 million years ago, making them among the oldest known horseshoe crab fossils worldwide, according to the report.
The fossils 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, along with trace fossils indicating attempts by the organisms to return to their natural position.
The finding provides rare evidence of ancient behavioral patterns and allows their interpretation in light of contemporary biological knowledge.
Geological stratigraphic analysis indicated recurrent intense seasonal storms during that period, suggesting that these organisms congregated in shallow coastal environments affected by such events, which contributed to their preservation in sedimentary deposits.
