Records of attempts to locate the kultarr, Antechinomys laniger (Marsupialia: Dasyuridae)

Introduction

Antechinomys laniger is a small carnivorous marsupial that inhabits a wide geographic range (Lidicker and Marlow 1970; Westerman et al. 2023). There are two recognised subspecies, A. laniger laniger and A. laniger spenceri, which show clinical variations in morphology and ecology (Archer 1977; Westerman et al. 2023). Archer (1981) assigned Antechinomys to subgeneric status within the genus Sminthopsis; however, this has since been contested by a genetic study by Baverstock et al (1982), and Antechinomys has been reinstated to its original generic status. The genetic study by Westerman et al. (2023) indicated that there are three distinct halogroups across its range. This study attempted to capture specimens from the New South Wales (NSW) and south-western Queensland lineage and from the far Western Australian lineage.

Antechinomys is found mainly in arid and semi-arid regions of interior Australia (Lidicker and Marlow 1970, p. 215, fig. 1; Valente 1984; Westerman et al. 2023, p. 96, fig. 1), with an apparently isolated population in the tropical region of the Northern Territory (Parker 1973). The nominate form (NSW/south central Queensland lineage) is known to inhabit savannah woodland where the ground cover varies from patches of grass and bare ground (Lidicker 1965; Lidicker and Marlow 1970; Maxwell et al. 1996; Ellis and Henle 1988) to salt marsh (Parker 1973). The ‘spenceri’ form has been recorded from a variety of habitats, including small ridges with tussocks and stunted vegetation (Wood-Jones 1923; Marlow 1965; Lidicker and Marlow 1970), woodland, tree steppe, desert associations (Ride 1970), gibber plains (Philpott and Smyth 1967; Parker 1973; Watts and Aslin 1974; Woolley 1984; Owens 1997), stony desert country (Anon 1964), hard sandy covered flats of the interior (Spencer 1896), spinifex country (Shortridge 1909; Marlow 1965), Mitchell grass plains, mulga and gidgee woodland (Parker 1973), and deserts dominated by Acacia, Eremophila and Cassia species (Strong and Low 1986).

Museum specimens of Antechinomys are mostly represented by individuals caught in the following three principle areas: the area bounded by Bourke, Cobar and Nyngan in northern-central New South Wales; central Australia encompassing the areas of south-western Queensland, northern and north-western South Australia and south central Northern Territory; and central Western Australia, particularly in the Murchison and Warburton districts (Westerman et al. 2023).

On the basis of the information on Antechinomys localities from museum collections, and discussions with colleagues on suitable areas, extensive trapping and spotlighting, from which a laboratory colony could be established, was conducted in south-western Queensland, central NSW and the Murchison region of Western Australia.

Materials and methods

The areas surveyed included Sandringham (24°03′S, 139°09′E), Mount Leonard (25°41′S, 140°45′E), Planet Downs (25°52′S, 141°07′E) and Glengyle (24°47′S, 139°35′E) stations, Queensland; El Trune (31°05′S, 146°25′E), Double Tanks (31°01′S, 146°41′E), Ramsey Park (30°50′S, 147°01′E), Harriet Park (29°38′S, 146°18′E), Gundabooka (30°24′S, 145°30′E), Gonella (30°43′S, 145°37′E), Toorak (30°13′S, 146°39′E) and Woodlands (31°50′S, 149°00′E) stations in NSW; and Mileura Station (26°22′S, 117°20′E) in Western Australia. The habitat in south-western Queensland was characterised by stony rolling country with tussock grassland of Mitchell grass, Astrebla spp., and scattered bushes of saltbush, Atriplex spp., and blue bush, Kochia spp. The habitat in New South Wales varied considerably, but was principally dominated by hard clay loams supporting the mulga scrub, Acacia aneura, and various eucalypts. Mileura Station, Western Australia, was characterised by scrub savananah, the dominant shrub being the mulga, Acacia aneura, with various species of Eremophila and Cassia.

Attempts to capture specimens of Antechinomys involved conventional line trapping with box and pitfall traps and spotlighting. The traps used were either Sherman aluminium box traps (23 cm × 8 cm × 9 cm), folding Elliott traps with perforated metal sides, top and rear, (26 cm × 10 cm × 10 cm), small Elliott aluminium box traps (23 cm × 8 cm × 9 cm) or large Elliott aluminium box traps (33 cm × 9 cm × 10 cm). Traps were set in either a single line in which the traps were spaced 50–100 m apart, or in three parallel lines, in which the traps were again spaced 50–100 m apart. Small Elliott or Sherman traps spaced 10 m apart were sometimes set both flush and parallel to a flywire drift fence (0.38 high × 100 m long), so that there were 10 traps per 100 m of fence, five on each side. Pits were dug 25 m apart to a depth of 45–60 cm and were straddled by a drift fence (see above). All traps, apart from the drift fence and pitfalls, were baited with a mixture of peanut butter and minced bacon. Traps were cleared by 0830 hours. Spotlighting was conducted from a vehicle driven along roads or over accessible country at either 15–25 km per hour, or 30–50 km per hour. The headlights of the vehicle were supplemented by spotlights fixed to the roof rack and by spotlights held in the hand.

Results

The survey in south-western Queensland was conducted during a 4-week field trip from 21 May to 14 June 1979. A total of 1890 trapnights was completed and 126 km of terrain was spotlighted. No Antechinomys was captured or seen. Three surveys were conducted in New South Wales, including 18–26 July 1979, 12 November to 7 December 1979 and 16–28 April 1980. In total, 3233 trapnights and 527 km of terrain were spotlighted. No Antechinomys was captured but three were spotlighted. These were sighted on El Trune Station on 20 July 1979, Ramsey Park Station on 25 July 1979 and 3 km west of Byrock (30°40′S, 146°24′E) on 5 December 1979. All sightings were made on open clay pans not far from thick mulga vegetation.

Overall, a total of 5123 trapnights was completed and 653 km of terrain was spotlighted. The number and type of small mammals captured on each visit to Queensland and New South Wales together, with the collecting effort expended, are given in Table 1. In total, 51 mammals were caught while trapping and spotlighting in these two states. Only three species of small, terrestrial mammal were recorded from south-western Queensland. Eleven Sminthopsis macroura individuals were captured by traps set on gibber plains on Sandringham Station. Most of the animals caught in New South Wales were Sminthopsis crassicaudata, the majority (21 individuals) by spotlighting on Toorak Station. Although live traps were set in the area traversed during spotlighting, no S. crassicaudata was caught in traps. Morton (1978) also reported on the trap shyness of this particular species of dasyurid. Two specimens of Sminthopsis murina were collected in NSW near the township of Coolabah (31°02′S, 146°43′E).

Between 31 May 1980 and 24 July 1982, four field trips were conducted on Mileura Station, Western Australia. In total, 21,126 trapnights and 2815 km of spotlighting were accomplished. Ninety-eight small mammals were captured (Table 2). Most of the Pseudomys individuals were captured on granite plains and the Notomys individuals were brought in by local Aboriginals mistaking them for Antechionmys. In total, 33 Antechinomys individuals (10 females, 23 males) were captured, 25 were trapped, and eight were collected by hand while spotlighting. All the Antechinomys were taken back to the laboratory to study their reproduction.

Discussion

The number of Antechinomys individuals captured per unit effort was extremely small. Low capture rates over extended periods of time have also been reported by other studies (Woolley 1984; Owens 1997). A. laniger spenceri showed a preference for habitat where granite plains predominate. The terrain is flat, except for laterite breakaway scarps and granite outcrops rising about 30 m above the plains. The soils are largely red, sandy loams, most of which are underlain by an understone hardpan to depths of 15–46 cm (Mabbutt 1963). In total, 24 specimens were collected from this area. Despite the extensive spotlighting on the wanderrie grass (Eragrostis lanipes)-dominated plains of Mileura Station, only nine (a total of 36 were sighted) Antechinomys individuals were captured in these areas.

Antechinomys was considered to be rare in the inland regions of Queensland and NSW by the Horn Expedition, which acquired only two specimens (Spencer 1896). Wood-Jones (1923) commented on its rarity in South Australia and at the time Lidicker and Marlow (1970) reviewed the genus, only 82 well preserved specimens were available for examination in museum collections. Finlayson found many specimens in the Northern Territory in the Everard and Musgrave ranges in 1932 and east of the Macdonnell Ranges between 1953 and 1956, and noted that ‘I found it fairly plentiful, much more so than any of the Sminthopsis species, …’ (Finlayson 1961: 157). Strong and Low (1986) sighted 29 individuals in 24 visits to three areas near and south of Alice Springs between August 1980 and August 1983. Parker (1973: 8) noted that Antechinomys is ‘not uncommon following good seasons, in a variety of country, …’. Antechinomys was considered to be abundant in south-western Queensland in 1966 (Woolley 1984). Lidicker (1965) captured one specimen near Cunnamulla, southern Queensland, in 107 trapnights. A field study in which four Antechinomys individuals (three males and one female) were fitted with radio-transmitters was conducted in 1997 in South Australia at Wire Bore Creek (Owens 1997). Caton (2007) based a laboratory study on three males and three females with pouch young captured between 2002 and 2004 from Andado Station in the Northern Territory. Another expedition captured six individuals in 2009 and 2010 in Idalia National Park and Diamantina National Park (D. Fisher, pers. comm., in Stannard and Old 2014). A summary of more recent captures and sightings has been provided by Stannard and Old (2014).

From 1967 to 1971, Antechinomys became increasingly scarce on Sandringham Station, south-western Queensland (Morton et al. 1977; Woolley 1984), and had seemingly disappeared from the area by 1979 (Woolley 1984). Many arid-zone mammals undergo changes in abundance, which correlate with the fluctuating environments of the arid regions (Finlayson 1939, 1961; Carstairs 1974; Watts and Aslin 1974; Newsome and Corbett 1975; Morton et al. 1977; Office of Environment and Heritage NSW 2012). Antechinomys (‘spenceri’ form) appears to be one of these animals, and populations wax and wane with the relative harshness of the environment. Finlayson (1961) attributed declining numbers to feral cat predation and Watts and Aslin (1974) identified local flooding as a cause for their disappearance. Woolley (1984) attributed the disappearance of the Antechinomys on Sandringham Station to the dramatic increase of the average rainfall in the area and possible overstocking and related habitat destruction following these ‘good’ seasons. However, Strong and Low (1986) found Antechinomys to be fairly common over a 3-year period south of Alice Springs in areas that were severely degraded by rabbits (Oryctolagus cuniculus) and cattle grazing.

Antechinomys (nominate form) appears to have become scarcer in NSW in recent times, although specimens have always been difficult to capture. Only two specimens were collected by the Blandowski expedition of 1856–1857, even though ‘high rewards were offered to the aboriginals at Gol Gol Creek’ to secure further specimens (Krefft 1866: 9). Five adult males and a female were captured by Lidicker and Marlow (1970) on El Trune Station in May 1964 and a further five were sighted by Lidicker near Cobar during a single night of spotlighting. Two specimens were sighted during five nights of spotlighting (3–4 h per night), but none was captured during 500 trapnights on El Trune Station in 1973 (P. A. Woolley, pers. comm.). No details of trapping and spotlighting effort were given by Lidicker and Marlow (1970), but the large number of sightings by Lidicker during a single night in 1964 seems to indicate that Antechinomys was relatively common in the area at the time. The sighting of only three individuals and the failure to trap any during the three NSW field trips (this study) suggests that Antechinomys was uncommon. The low numbers may be due to the severe drought the region was experiencing at the time and the accompanying habitat destruction by soil erosion and overgrazing. Habitat degradation through grazing and introduced species such as the rabbit (Oryctolagus cuniculus) was identified as a possible cause for population declines in NSW (Stannard and Old 2014). Another potential threat to Antechinomys numbers in NSW is the use of insecticides to control locusts. Past locust control measures overlap Antechinomys habitat (NSW National Parks and Wildlife Service 2002). The same report suggests that the past use of 1080 poison (sodium monofluroacetate) may have had a detrimental effect on Antechinomys numbers. The historical declines indicate that Antechinomys (nominate form) is rare and possibly endangered over its range, especially in the southern and north-eastern parts (Dickman et al. 1993). The population in NSW may have declined to a critical level (New South Wales National Parks and Wildlife Service 2002).

Many of the museum specimens of Antechinomys (‘spenceri’ form) from Western Australia originate from the Murchison and Warburton regions. Although Burbidge and McKenzie (1989) considered that numbers have remained stable over the known range, there is no indication in the literature of their relative abundance over the years. Dickman et al. (1993) considered the species to be vulnerable on a national level. Antechinomys has regularly been sighted on Mileura Station since 1960 when the CSIRO Division of Wildlife Research established a field centre on the station (S. J. J. F. Davies, pers. comm.). The consistent low trapping success for specimens on Mileura Station appears to be due to the low numbers rather than the possible trap shyness of this species. Spotlighting at night was shown to be a convenient method of indicating relative abundance of Antechinomys. Although it was impossible to spotlight all areas methodically and effectively, because of the growth of perennial vegetation in spring, it indicated that the animals were not abundant in the area.

Antechinomys (‘spenceri’ form) showed a distinct preference for the stony granite plains over the wanderrie plains on Mileura Station. This observation contrasts strongly with Wood-Jones’ (1923) statements that Antechinomys (‘spenceri’ form) occupied sand ridges with tussocks and stunted vegetation and with Shortridge (1909) who found them in spinifex country. Reports of Antechinomys having been captured on stony or gibber plains are described in Anon. (1964), Philpott and Smyth (1967), Parker (1973), Watts and Aslin (1974), Morton et al. (1977), Woolley (1984), Strong and Low (1986) and Owens (1997).

The three Antechinomys (nominate form) individuals sighted in NSW were associated with sparsley vegetated clay pans among Acacia woodland. Similar habitat descriptions have been given by Lidicker (1965) and Lidicker and Marlow (1970). The report by Lidicker and Marlow (1970) that hollow logs and stumps are used by the nominate form as retreats agrees with the observation of a specimen evading capture when it disappeared into a large hollow log on Ramsey Park Station.