Like its namesake, a fossil named after Bowie raises many questions
Ancient South American mammal co-existed with dinosaurs, had relatives in India. Jeff Glorfeld reports.
The late British artist David Bowie has been feted for his vast catalogue of musical achievements, but now he has been further memorialised in palaeontology, with the naming of Brasilestes stardusti, the oldest known mammal found in Brazil.
B. stardusti, named for Bowie’s 1972 creation Ziggy Stardust, lived in what is now the north-west of São Paulo state at the end of the Mesozoic Era, between 87 million and 70 million years ago. It is the only Brazilian mammal known to have coexisted with the dinosaurs.
The discovery was announced in a paper in the journal Royal Society Open Science by a team led by Max Langer, from Brazil’s University of São Paulo.
Identification of the new species rests on a fossilised premolar tooth with a crown length of just 3.5 millimetres.
“The tooth is small and incomplete – the roots are missing,” says lead author, palaeontologist Mariela Cordeiro de Castro.
“Although it's only 3.5 millimetres, the Brasilestes tooth is three times bigger than all known Mesozoic mammal teeth. In the age of the dinosaurs, most mammals were the size of mice. Brasilestes was far larger, about the size of an opossum.”
The research is part of a larger project, investigating the origin and rise of dinosaurs in the Gondwana super-continent, with Langer as principal investigator.
The incompleteness of the tooth prevents the researchers from saying with absolute confidence to which group of mammals the species belonged. They know only that the tooth belonged to a therian, a member of a large subclass that includes marsupials and placentals.
Although there is not enough evidence to support the inclusion of B. stardusti in either infraclass, the researchers believe it was a placental mammal. If so, the fossil is unique.
Langer says the Bowie beast is different from everything found before, suggesting that possibly placental mammals inhabited South America as early as 87.8 million years ago.
The Mesozoic mammal with premolars that most resembled the B. stardusti tooth lived on the other side of the world, in India, between 70 million and 66 million years ago. Its name is Deccanolestes.
“The discovery of Brasilestes raises many more questions than answers about the biogeography of South American Mesozoic mammals,” Langer says.
“Thanks to Brasilestes, we've realised that the history of Gondwana's mammals is more complex than we thought.”