云南大学和莱斯特大学的研究人员在中国云南省澄江化石遗迹发现了一块距今5.18亿年的Urokodia化石，为现代蜘蛛和蝎子的獠牙提供了迄今已知的最早证据[1]。通过X射线断层扫描技术，科学家们在这种体长约2-3厘米的小型海洋生物化石中发现了位于眼睛后方的两个钳子状附肢结构[1]。
云南大学刘宇教授表示："我们使用X射线断层扫描分析这些化石，以揭示埋藏在岩石中数亿年的软体结构，突然我们注意到了动物前部的钳子状肢体"[1]。
这些钳子状附肢代表了现代螯肢类动物（包括蜘蛛和蝎子）的獠牙和钳子的早期进化形式[1]。该研究已发表于《自然》期刊[1]。
Researchers have discovered fossil evidence of the earliest known fangs of modern spiders and scorpions in a 518-million-year-old creature called Urokodia [1]. Scientists from Yunnan University and the University of Leicester identified pincer-like limb structures positioned behind the animal's eyes using X-ray tomography scanning, representing the ancestral form of the chelicerae—the fangs and claws found in modern chelicerate arthropods [1].
The tiny marine organism, measuring approximately 2-3 centimeters in length, was preserved in the Chengjiang fossil site in Yunnan Province, China [1]. Professor Liu Yu from Yunnan University, who led the research published in Nature in 2026, explained the discovery process: "We were using X-ray tomography analysis of these fossils to reveal their soft anatomy buried in the rocks for hundreds of millions of years, when suddenly we noticed the pincer-like limbs at the front of the animal" [1].