Paleontologists at the University of New South Wales have described a new genus and species of dasyurid marsupial from the Early Miocene of Australia, offering the first solid evidence that the family Dasyuridae — which today includes quolls, Tasmanian devils and tiny antechinuses — existed long before scientists had proof of it in the fossil record.
An artist’s reconstruction of Miyumba chrisdickmani in the Early Miocene rainforests of northern Australia. Image credit: Nellie Pease.
Named Miyumba chrisdickmani, the new species lived roughly 18 million years ago in the lush rainforests of what is now northwestern Queensland.
The marsupial weighed an estimated 23 to 33 grams, roughly the size of modern antechinuses or dunnarts.
“Dasyurids are the most speciose family of the marsupial order Dasyuromorphia and the second-most species-diverse family of Australian marsupials with 67 living species in 21 genera,” said lead author Dr. Timothy Churchill and his colleagues from the University of New South Wales.
“The fossil record contains 20 dasyurid species in eight genera that include living species and two genera that include only living species known from Australian Plio-Pleistocene deposits.”
The paleontologists unearthed several partial lower jawbones of Miyumba chrisdickmani at sites within the Riversleigh World Heritage Area, a fossil-rich region in Queensland.
They used micro-CT scanning to examine the specimens’ teeth in detail and compare them against dozens of living and extinct relatives.
They identified a new dental feature that appears to be shared by all dasyurids, providing what researchers describe as the first reliable anatomical trait uniting the entire family.
Until now, no dental characteristic had definitively distinguished dasyurids from their close relatives, complicating efforts to trace the group’s origins.
The analyses of the fossils’ anatomy, combined with genetic data from living species, indicate Miyumba chrisdickmani branched off before all other known dasyurids, making it the oldest and most primitive member of the family yet discovered.
According to the researchers, the broader dasyurid lineage originated around 25.6 million years ago, approximately three million years earlier than previous estimates had suggested.
They also found that Miyumba chrisdickmani shares notable dental similarities with living rainforest-dwelling marsupials found today in New Guinea, such as species of Murexia.
They propose that the new species may represent an early branch of a lineage that later persisted in New Guinea’s rainforests after Australia’s own forests contracted and dried out over the past several million years.
“New Guinea has retained extensive rainforest cover since the Miocene, preserving a faunal assemblage that likely reflects the ecological structure of Sahul’s former lowland rainforests,” the scientists said.
“This includes a diverse radiation of rainforest-adapted dasyurids, some of which may share a close relationship with Miyumba chrisdickmani.”
“Several marsupial lineages that were once more widespread across Sahul are now restricted to New Guinea.”
“Miyumba chrisdickmani appears to represent a comparable case — a Miocene rainforest-adapted dasyurid lineage whose descendants may have persisted in New Guinea following the collapse of closed forests on the Australian mainland.”
The discovery of Miyumba chrisdickmani is reported in a paper published July 17 in the journal Australian Zoologist.
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Timothy J. Churchill et al. 2026. A new genus of dasyurid Miyumba chrisdickmani (Marsupialia, Dasyuridae) from the Early Miocene deposits of the Riversleigh World Heritage Area, north-western Queensland. Australian Zoologist 45 (2): AZ26024; doi: 10.1071/AZ26024
