Pseudobaphia biesiana – Rare Potentially Extinct Unionidae from Sichuan

Pseudobaphia biesiana, potentially extinct and originating from Sichuan Province, China, is one of the rarest species worldwide. Since its initial discovery, only a handful of specimens have been recorded, all from the original period of description. No new individuals have been found in over 150 years. The current specimen is a post-mortem shell, with no living populations observed. Although the collection locality deviates slightly from the type locality, its morphological characteristics match perfectly with the type series, making it a significant find for scientific study on freshwater mollusk extinction.