Bettongia ogilbyi (Waterhouse, 1841) Newman-Martin & Travouillon & Warburton & Barham & Blyth, 2025

Bettongia ogilbyi

Within specimens of Bettongia ogilbyi from the southwest of Western Australia, two morphologies were identified. Two subspecies were initially identified based on the sexual dimorphism present, wherein the females of Bettongia ogilbyi sylvatica were near equal in size to the males of Bettongia ogilbyi ogilbyi . This is visible in the craniodental morphological analysis (Fig. 4, 5, 6, 7, 8, and 9), and supported by the PERMANOVA analysis conducted ( Table 1-12) which indicated both taxa represent a subspecies within B. ogilbyi . Of these taxa, the new subspecies was named Bettongia ogilbyi sylvatica after the forest environments where specimens were predominantly found (Supp. 4). PERMANOVA analyses comparing B. o. sylvatica and B. o. ogilbyi demonstrated significant difference cranially ( Table 3), as well as for the upper dental ( Table 7), and lower dental ( Table 11). When allometry corrected, the results showed a similar result based on cranial ( Table 4), upper dental ( Table 8), and lower dental ( Table 12) characters.

However, our findings are contra to those of previous genetic investigations ( Pacioni et al. 2011; Pacioni, 2014), Bettongia ogilbyi is one of the most well studied mammals in Australia, mainly due to the large amount of conservation and translocation efforts undertaken ( Short, 2009), with genetic work used in the management of population diversity ( Pacioni et al. 2011; Pacioni, 2014). In fact, B. ogilbyi was the first member of Potoroidae with a reference genome (Peel et al. 2021). Prior to this, the majority of genetic work on B. ogilbyi used mitochondrial DNA (mtDNA) sequences such as Cytochrome b (Cytb), as evidenced by Genbank, where (at the time of writing) of the 123 accessions for B. oglibyi , only two use nuclear DNA (nDNA). The use of mtDNA in taxonomy has previously come under scrutiny, and it has been suggested it should not be exclusively used when identifying species (Rubinoff, & Holland, 2005). This is because mtDNA can be of little utility when attempting to identify closely related species (Rubinoff, Cameron, & Will, 2006). Instead, it is suggested that a combination of mtDNA and nDNA should be used for taxonomic purposes (Rubinoff, Cameron, & Will, 2006). Examples of closely related taxa being misidentified due to the exclusive use of mtDNA include rock wallabies ( Petrogale spp. ) and short-nose bandicoots ( Isoodon spp. ). In the case of the latter, initial genetic work by Pope et al. (2001) using mtDNA could not differentiate between I. obesulus and I. auratus . Later work by Westerman et al. (2012) used a combined mtDNA and nDNA taxonomic approach that could clearly differentiate the species. In the case of rock wallabies ( Petrogale spp. ), genetic work using mtDNA was inconsistent with that of nDNA, and clarity could only be brought to the taxonomy of the species once a combined approach was used ( Eldridge & Close, 1992). Many genetic investigations traditionally use samples from live B. ogilbyi , and only the work by Pacioni et al. (2015), and Haouchar et al. (2016) including historical museum and subfossil specimens. Whilst Pacioni et al. (2015), and Haouchar et al. (2016) used mtDNA, the use of a wider array of material in these studies allowed for more genetic material to be represented and thus more potential for unidentified taxa.

Prior to the work of Pacioni et al. (2015), and Haouchar et al. (2016), no outliers were observed in the genetics of the B. penicillata complex. This indicates that the conclusions drawn from a substantial amount of genetic research conflicts with the results of our investigation, where more taxa than B. haoucharae (Clade 1 in Haouchar et al. 2016) were identified. Unfortunately, the genetic data of Pacioni et al. (2015) cannot be matched with physical specimens, as the registration numbers of the material genetically analysed were not recorded. Additionally, it is known that some genetic material from Pacioni et al. (2015) failed to sequence (Supporting information Table S1, Pacioni et al. 2015). Without registration numbers it is not possible to know if material failing to sequence is the reason for taxa being overlooked, or if specimens were not sampled. A lack of Museum registration numbers in Bettongia penicillata genetic reports is not unusual, with other investigations ( Pacioni et al., 2011; Haouchar et al. 2016) also lacking this information. This also extends to the genotyped specimen for the Woylie (WAM M65253), which was registered after the Peel et al. (2021) report was published.

The authors were, however, able to link molecular samples in Pacioni et al., (2011) to Bettongia ogilbyi ogilbyi . In a molecular investigation by Pacioni et al., (2011), it was determined that four genetically distinct indigenous populations were present within the southwest, those being the populations at Perup, Kingston, Dryandra woodland and Tutanning Nature Reserve. Of these populations the individuals at the Tutanning Nature Reserve were noted as being the most genetically distinct. When comparing specimens at the Western Australian Museum, a single specimen was found from Kanyana Wildlife Rehabilitation Centre (WAM M65249) an adult male collected in 2014. This individual is the most recent modern specimen of B. o ogilbyi in the WAM, with the last B. o. ogilbyi from 1973 (pers. obs. Newman-Martin and Travouillon). In 2012 several wild individuals from the Tutanning population were delivered to the Kanyana Wildlife Rehabilitation Centre to establish a breeding population (pers. comm. Tara Jenkins to Newman-Martin & Travouillon, 2024). Upon inquiring into the status of these individuals with the Kanyana Wildlife Rehabilitation Centre, it was discovered that there is a single individual left, an elderly female named “Bad-Leg” (pers. comm. Tara Jenkins to Newman-Martin & Travouillon, 2024). However, in February of 2022 three Tutanning males were sent from the Kanyana Wildlife Rehabilitation Centre to Whiteman Park, though their status is unknown (pers. comm. Tara Jenkins to Newman-Martin & Travouillon, 2024). There have been confirmed observations of wild B. o. ogilbyi in the Tutanning area (pers. comm. Kate Rick to Travouillon, 2024). With only the wild population at Tutanning known, this means that the wild population of B. o. ogilbyi is very low and in critical need of reassessment and protection.