Disentangling the Genetic Relationships of Three Closely Related Bandicoot Species across Southern and Western Australia

Abstract

The taxonomy of Australian Isoodon bandicoots has changed continuously over the last 20 years, with recent genetic studies indicating discordance of phylogeographic units with current taxonomic boundaries. Uncertainty over species relationships within southern and western Isoodon, encompassing I. obesulus, I. auratus, and I. fusciventer, has been ongoing and hampered by limited sampling in studies to date. Identification of taxonomic units remains a high priority, as all are threatened to varying extents by ongoing habitat loss and feral predation. To aid diagnosis of conservation units, we increased representative sampling of I. auratus and I. fusciventer from Western Australia (WA) and investigated genetic relationships of these with I. obesulus from South Australia (SA) and Victoria (Vic) using microsatellite markers and mitochondrial DNA. mtDNA analysis identified three major clades concordant with I. obesulus (Vic), I. auratus, and I. fusciventer; however, I. obesulus from SA was polyphyletic to WA taxa, complicating taxonomic inference. Microsatellite data aided identification of evolutionarily significant units consistent with existing taxonomy, with the exception of SA I. obesulus. Further, analyses indicated SA and Vic I. obesulus have low diversity, and these populations may require more conservation efforts than others to reduce further loss of genetic diversity.

Modeling genetic benefits and financial costs of integrating biobanking into the conservation breeding of managed marsupials

“…Backcross scenarios tested: 90%, 95%, and 99% heterozygosity retention with no backcross and backcross every generation. Colony numbers derived using a published N e of 0.34 for dibblers (Thavornkanlapachai, 2016) and an assumed mean N e estimate for captive vertebrate populations of 0.3 (Mace, 1986) to represent numbats.…”

“…(2021). We derived required colony sizes based on the published N e / N of 0.34 for the dibbler (Thavornkanlapachai, 2016) and 0.3 for the numbat (mean N e / N value for captive vertebrates used in previous modeling without species‐specific values) (Howell, Frankham, et al., 2021; Howell, Mawson, et al., 2021; Howell et al., 2022; Mace, 1986).…”

Habitat selection by vulnerable golden bandicoots in the arid zone

“…Second, a higher density of animals and associated intraspecific competition and territorial behaviors may be interacting with the resource-rich spinifex to constrain bandicoot home ranges (Schradin et al, 2010). , 1991;Thavornkanlapachai et al, 2021;Travouillon & Phillips, 2018).…”

“…Territorial behaviors, however, have not been observed in closely related southern brown bandicoots (Isoodon fusciventer) (Broughton , 1991;Thavornkanlapachai et al, 2021;Travouillon & Phillips, 2018).…”