Fossil of Qingjiangonema cambria （Image source：Cui L et al. (2024)， CC BY 4.0 ） 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-