Scientists have discovered early fossil remains tracing the ancestry of one of the world's most expensive aquarium fish - the endangered Asian arowana.
The discoveries in Central China's Hunan and Hubei provinces are helping scientists understand how this prized fish spread throughout the world, read the latest edition of Vertebrata Palasiatica.
The species, Scleropages sinensis, is an ancient variety of the Asian arowana, explained the paper's authors, Zhang Jiangyong with the Chinese Academy of Sciences and Mark Wilson, professor at the University of Alberta, Canada.
The discovered fossils - which are in near perfect condition - are significant in revealing where large freshwater fish lived in the tropical zone, according to Zhang and Wilson.
The fossils date back to the Early Eocene, or 56 to 33.9 million years ago, the epoch when the newly-discovered variety split from its ancestors, the journal reads.
However, the fish now protected by the Endangered Species Act, and fetches prices rumored to reach $300,000, reported National Geographic.
