A bandicoot skull given to a museum by a widow in 1920 belongs to a species that went extinct before it had a name

A bandicoot skull donated in 1920 belongs to the little brown bandicoot, a new extinct species, in a study of 800 specimens that lists 7 Isoodon species.

Mrs. Symonds Clark lost her husband on July 10, 1920. In October she handed one of his bandicoot skulls to the South Australian Museum in Adelaide. It went into the drawers as "SAMA M1981, skull only, sex unknown," and was later labeled as a golden bandicoot.

The ear capsules on it were far too small for that.

Kenny Travouillon of the Western Australian Museum and eight co-authors have now made SAMA M1981 the type of a new species, the little brown bandicoot, Isoodon microtis.

It most likely came from Eyre Peninsula and was gone before anyone noticed. Three skulls and some jaw fragments are all that is left of it.

Three skulls without dates

The paper lists the Adelaide skull as probably female, going by its smaller canines. Two more skulls turned up at Museums Victoria in Melbourne under the label Isoodon sp., with no data except that they came from a Mr. Waterhouse.

DNA was tried on all three and none came back usable. So the species stands on skull and tooth characters. In the team's combined analysis it lands next to the southern brown bandicoot, even though it shared Eyre Peninsula with a quenda.

Microtis is Greek for "small ear." It is the smallest Isoodon in overall size. Its bullae are also smaller relative to the skull than in any other member of the genus.

Symonds Clark's diary and a ledger

Symonds Clark kept birds and studied them, and he sometimes collected mammal skulls for the museum. The team dated his skull to between 1876, his last logged donation, and 1914. That is the last entry in his diary, now at the State Library of South Australia.

None of the bandicoots in the diary could be matched to it for sure. His only trip out of Adelaide in those years was to Eyre Peninsula.

The Melbourne pair goes back to Frederick George Waterhouse, the museum's first curator from 1861 until he resigned in February 1882.

His reports mention two bandicoots shipped to Melbourne between November 1866 and January 1867, which puts their collection between 1862 and 1866.

In those years the catalogue shows five bandicoot donations, from a stuffed one given by a Mr. L. Clark in July 1864 to two skins from a Mr. Andrews, and the localities were not always recorded.

The place came instead from subfossil jaws in Adelaide, three lower and two upper, from at least three animals. They were dug at the South Block Site near Edillilie, about 5 miles (8 kilometers) east of Coulta, in an area not cleared for agriculture.

Over 800 specimens, 17 collections

Travouillon has said the work started in 2016, with visits to bandicoot collections in Europe and the United States.

The paper credits the Winston Churchill Memorial Trust and the Australian Biological Resources Study (ABRS) for funding his access to specimens. Steven Cooper and Terry Bertozzi of the South Australian Museum and Adelaide University came in later.

In the end the team examined more than 800 specimens in 11 Australian collections and in London, Paris, Genoa, Munich, Washington and New York. Every available type specimen of Isoodon was examined and sampled for DNA, according to the paper.

DNA came from 83 fresh tissue samples and 75 historical ones. Pieces of dried skin were soaked overnight before extraction. That work ran in a trace DNA lab at the Australian National University, set apart from the main lab to keep modern DNA out.

The Oz Mammals Genomics Initiative did the sequencing. After filtering, 2,050 gene regions were left, about 1.14 million DNA letters, and the specimen list is posted on Dryad.

Seven species, seven new subspecies

Eleven Isoodon species have been described over time. The 1990s revisions brought that down to three, and studies in 2012 and 2018 raised it to five. Now it is seven.

The other new one is the New Guinea brown bandicoot, Isoodon moresbyensis, named from Port Moresby in 1877 and later lumped in with the northern brown bandicoot. Its DNA is deeply split from that species and its skull is much smaller.

The Kimberley golden bandicoot is now I. auratus bundilarri, from the Uunguu word for the animal on Wunambal Gaambera Country, and its type is a young male from the Mitchell Falls campground.

A south coast quenda, I. fusciventer halae, honors Marie Hale, the first person to pick it out. The rest come from Daw Island, St Francis Island, Marchinbar Island, Cape York and the Adelaide Hills.

Measurements and genes recently split Sydney's funnel-web spider into three species. Old specimens also made up much of the 2025 haul of new species from museum cabinets.

The quenda reaches Kangaroo Island

The quenda, Isoodon fusciventer, used to be a Western Australian species. Bandicoots from the Mount Lofty Ranges, Kangaroo Island and the Nuyts Archipelago now belong to it as well. The western and South Australian groups separated around 800,000 years ago, the team estimated.

The mainland South Australian quenda is I. f. terrenus, Latin for "earthly," since it is not an island form. Its type, SAMA M25880, is an adult male taken 6.7 miles (10.8 kilometers) west-southwest of Mount Barker.

The subspecies once ran from the Murray River to coastal Eyre Peninsula but is now down to the Mount Lofty Ranges, Fleurieu Peninsula and Kangaroo Island.

That shrinks the southern brown bandicoot, Isoodon obesulus obesulus, to the coast from Sydney to southeast South Australia. It is already listed as endangered federally, and the authors call for an urgent review of its status.

Australia has lost 42 mammal species since European colonization, and nearly 20 percent were bandicoots and bilbies, the paper notes.

Foxes, cats, land clearing and changes to traditional fire practices are blamed. DNA testing has also shown that feral cats kill more native animals than expected.

When the little brown bandicoot died out

There is no date for the extinction. The last of the skulls was in the museum by October 1920. Land clearing for farms was well under way on Eyre Peninsula in the late 1800s.

If the species lasted until foxes arrived, the authors wrote, "it is very likely that foxes would have played a role in its extinction."

Marchinbar Island's golden bandicoot is known from just two specimens, and no genetic samples exist for the Cape York northern brown bandicoots. The IUCN Red List was last updated for Australian mammals in 2016.

The authors suggest that I. f. terrenus, which shared Eyre Peninsula with the little brown bandicoot, could be reintroduced there, though "it would be difficult to find an ecological analogue to replace it."

Craig Moritz and an anonymous referee reviewed the paper, which went in on December 17, 2025, and came out on October 14, 2026. SAMA M1981 is still in Adelaide, now as the type of its own species.

The full study was published in the journal Australian Journal of Taxonomy.

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