Pangolins are among the world's most endangered species and their scales are prized in traditional Chinese medicine as a remedy for various ailments, although there is no scientific evidence they have medicinal value.
Nigeria is a major hub for traffickers sending their scales to Asia.
Nigerian police said they had "successfully arrested and repatriated a Chinese fugitive, Cai Jinlian" to Shanghai to face wildlife trafficking charges.
The 42-year-old smuggled "approximately 12 tonnes of tree pangolin scales" from Nigeria to China in two consignments between November 2018 and April 2019, police said in a statement.
An international arrest warrant was issued in 2020 after Cai fled from China to Egypt before relocating to Nigeria.
