Bobi, previously crowned the world's oldest dog, has lost his title due to inconclusive evidence of his age, Guinness World Records (GWR) announced Thursday.
A Guinness review launched last month concluded it "no longer has the evidence it needs to support Bobi's claim as the record holder".
Bobi died last October at the age of 31 years and 165 days, exceeding the 12-14 years life expectancy for his breed, Rafeiro.
He was crowned the oldest living dog and the oldest dog of all time in February 2023, having lived a life surrounded by cats in a house in Conqueiros, a small village in central Portugal.
Bobi was originally recognised by Guinness at the age of 30 years and 266 days.
But after the dog's extraordinary longevity raised a several questions among experts, Guinness suspended the title January, pending investigation.
At the time, Bobi's owner Leonel Costa said the suspicions were "unfounded".
Guinness relied on microchip data sources from the Portuguese government's pet database, "SIAC".
When Bobi was chipped in 2002, SIAC "did not require proof of age for dogs born before 2008", Guinness adjudicator Mark McKinley said in a statement.
"We are not yet in a position to confirm a new holder for the record," Guinness added.