Northern Suburbs Branch November 2020
Our speaker, Dr Kenny Travouillon, has been the Curator of Mammalogy at the WA Museum since 2015. Having studied the 10 to 24 million year old fossil remains of bandicoots found at Riversleigh, Queensland for his PhD, it was only natural for him to take an interest in the WAM collection of more recent species after he arrived in Perth.
The Western Barred Bandicoot was of particular interest because of what was known as the Perameles bougainville complex. This complex, made up of five species with similar characteristics, had been described by different people over a period of almost one hundred years (1824 – 1922).
Kenny’s research quickly lead to the conclusion that the few studies undertaken in the second half of the 1900s were hampered by the lack of access to the many specimens collected by early naturalists and collectors as these were now held by numerous overseas museums and institutions.
He successfully applied for a Churchill Fellowship in 2016 which enabled him to travel around the world to study all the known collections of bandicoots in Europe and America as well as those in Australian museums.
To determine if they were in fact different species, Kenny took skull measurements of all the available specimens. He found the results did fall into clusters, thereby discriminating between species. Contrary to expectations, there was no consistency between gender and skull size; in some species the male was larger, while in others it was the female.
Specimens of the Pig-footed Bandicoot were collected on opposite sides of the continent in the first half of the nineteenth century. Chaeropus ecaudatus was collected by surveyor Major Thomas Mitchell on the banks of the Murray River in NSW in 1836. A few years later, in 1845, John Gould named one of the two specimens collected by John Gilbert in WA, C. occidentalis, which was later synonymised within C. ecaudatus, and now recognised as a subspecies of C. ecaudatus. Based on the unusual bone structure of the feet, Gould surmised the animal walked on two toes on the front feet and one toe of the rear.
In recent years, mitochondrial and nuclear DNA have been used to build dendrograms which confirm the specimens, now held by Museum Victoria and the Natural History Museum in London, are distinct species.
In 2019 Kenny described a new species, Chaeropus yirratji, which had first been collected by Captain Charles Sturt in 1844-45 in South Australia, but is now housed in Paris. Apparently Sturt sent a specimen to Gould in London who later exchanged it for some hummingbirds. This species inhabited areas of sandplains and dunes with spinifex and tussock grasses in central Australia and was the last species to become extinct, around 1950, probably because it took longer for its chief predator, the fox, to spread that far. The Western Barred Bandicoot, Perameles bougainville, (Marl) as now described has been reintroduced from two Shark Bay islands.
Kenny concluded his presentation by discussing his recent work on Quendas, until recently thought to be a subspecies of the Southern Brown Bandicoot (Isoodon obesulus). However, there is now sufficient evidence to elevate the Western Australian population to its own species, Isoodon fusciventer.
Large and Small forms of Quenda (Isoodon fusciventer) Image: K. Travouillon
But not all Quendas are the same.
Again, using skull measurements, Kenny and co-workers have found a “large form” and a “small form”.
The former appears to be restricted to the forested areas around Perth and the suburbs, while the small form is most common in the Wheatbelt and along the South Coast.