Guang Yang of Nanjing Normal University and Michael Bruford of Cardiff University in Wales led the research, the BBC reported. Their findings were published in the journal Marine Biology.
"The most surprising finding of this study is that the Yangtze finless porpoise represents a distinct genetic grouping, which is distinct from marine porpoises," Yang said.
There are three populations of finless porpoises, in the Yellow and South China seas and in the Yangtze. The team analyzed the DNA of 125 specimens and found each group has unique genetic characteristics with the freshwater porpoises so different from their saltwater cousins they could be a separate species.
Yang said a 2006 field survey estimated the surviving population in the Yangtze at 1,000, a sharp drop in 20 years. The government is considering upgrading the porpoise's conservation status.
The Baiji, a river dolphin living in the Yangtze, was declared extinct in 2007. That is the only known extinction of a cetacean species since scientists began keeping records although several are considered at risk.
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