Machairodontinae, including the famous Smilodon and Homotherium, was an iconic Pleistocene carnivore lineage that occupied a critical ecological paleo-niche and is thought to have had a profound impact on Ice Age ecosystem structure. Recent ancient molecular studies on Homotherium suggest a wider distribution than inferred from the fossil record, highlighting a need for additional fieldwork, fossil collection, and research in understudied geographic regions. After the original publication 80 years ago that identified a Pleistocene carnivoran fossil as Felis sp. in Taiwan, here we revise its identification and demonstrate the presence of the large machairodontine cat, cf. Homotherium sp., in the Pleistocene of Taiwan, suggesting the easternmost occurrence of this lineage in Eurasia. Our results also exemplify the importance of fossil curation and in-depth research to reveal regional hidden diversity and lost ecosystem structure for understanding faunal turnover and the origin of modern biodiversity.