Fossil of Qingjiangonema cambria （圖片來源：Cui L et al. (2024)，採用  CC BY 4.0  授權） Age Cambrian（" Stage 3 "） 518 Ma Taxonomy Domain: Bacteria Kingdom: Pseudomonadati Phylum: Desulfobacterota Genus: Qingjiangonema Species: Qingjiangonema cambria Morphological description Qingjiangonema cambria  is preserved as abundant straight, unbranched, and extremely slender filaments. Each filament is approximately 1–3 μm in diameter and can reach lengths of up to about 1 mm. These thread-like