Sminthopsis butleri, Archer, 1979

Russell A. Mittermeier & Don E. Wilson, 2015, Dasyuridae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 232-348 : 336-337

59.

Butler's Dunnart

Sminthopsis butleri

French: Dunnart de Butler / German: Butlers SchmalfuRbeutelmaus / Spanish: Raton marsupial de Butler

Other common names: Carpentarian Dunnart, Munjol

Taxonomy. Sminthopsis butler: Archer, 1979 , Kalumburu (14° 15° S, 126° 40’ E), Western Australia, Australia.

Much attention has been given to resolution of the dunnart group, both morphologically and genetically, but unfortunately its taxonomy remains unclear. A recent genetic phylogeny (several mitochondrial and nuclear genes) failed to support monophyly of the genus Sminthopsis with respect to Antechinomys and Ningawi. There were three deeply divergent clades of Sminthopsis . In the first clade, S. longicaudata was sister to A. laniger . The second clade was the traditional, morphologically based Macroura Group: five Sminthopsis comprised a strongly supported clade, which included S. crassicaudata , S. bind, S. macroura, S. douglasi , and S. virginiae . This clade of five dunnarts was a poorly supported sister to the three species of Ningaui (N. rider, N. timealeyi , and N. yvonneae). The combined clade of five Sminthopsis and three Ningaui was positioned as a poorly supported sister to a well-supported third large clade containing the remaining species of Sminthopsis (13 species in the Murina Group). This large dunnart clade contained a well-supported sister pairing of S. archeri , with a clade containing five species: S. murina , S. gilberti, S. leucopus , S. butleri , and S. dolichura . S. butleri was named by M. Archer after naturalist H. Butler, who found the holotype at Kalumburu near the mouth of the King Edward River, in the Kimberley region of Western Australia. Genetically, S. butleri is part of a well-supported clade with S. leucopus and S. dolichura . Dunnarts collected on Cape York, and previously considered to be S. butler , are now recognized as a distinct species, S. archeri . S. archeri and S. butler : are distinctly different genetically. Monotypic.

Distribution. N Australia, where it has a very limited mainland distribution (Kulamburu, Kimberley region) in Western Australia, also on the Tiwi Is (Bathurst and Melville Is) in Northern Australia.

Descriptive notes. Head-body 8-8 cm, tail 9 cm; weight 15-30 g. Butler’s Dunnart has soft fur and is grayish above and white below. There is a vague head stripe. Tail is invariably thin and sparsely furred. Butler’s Dunnart can be distinguished from the sympatric Red-cheeked Dunnart (S. virginiae ) by absence of rufous fur on cheeks.

Habitat. Not consistently associated with any particular habitat type on the Tiwi Islands but found in eucalypt open-forest and woodland dominated by Eucalyptus tetrodonta, E. miniata, and Corymbia nesophila (all Myrtaceae ). These habitats may have flat sandy substrates or outcropping rocks and boulders. Butler's Dunnart also occurs in lower densities in Melaleuca (Myrtaceae) woodland and on edges of treeless plains. All known records on Northern Territory islands have come from within 20 km of the coast. Butler’s Dunnart does not occur in plantation forests. Habitat in Kimberley where it was first discovered was heavily vegetated where back-soil country met sand plains (adjacent to an air strip); ajuvenile Butler's Dunnart was found among flood debris nearby.

Food and Feeding. There is no specific information available for this species, but like other dunnarts, Butler’s Dunnart most likely preys mainly upon invertebrates and perhaps small vertebrates.

Breeding. A female Butler's Dunnart (the holotype) collected in Kimberley on 12 December 1965 was carrying seven pouch young. In Northern Territory, breeding may be seasonal, with reproductively active females being recorded in August-December. Litters of up to nine young have been recorded.

Activity patterns. There is no specific information for this species, but Butler's Dunnart is most likely ground dwelling, sheltering under logs and other cover.

Movements, Home range and Social organization. There is no information available for this species.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. Listed as vulnerable in Australia. Extent of occurrence of Butler's Dunnart is less than 20,000 km?, all individuals are known from less than ten locations, and there are continuing declines in areas of occupancy, extent and quality of suitable habitat, and number of mature individuals due to introduced predators and destruction and degradation of habitat. Butler’s Dunnart was described from just a few specimens collected in 1965-1966 from Kalumburu (near the mouth of King Edward River at the bottom of the airstrip) in the Kimberley, Western Australia. Subsequent survey work in June 1991 failed to locate Butler's Dunnarts in the Kimberley, where its continued presence is uncertain. Nevertheless, the 1991 survey was conducted in an area only recently burned and where domestic and feral cats were present; such factors probably limit local populations of Butler’s Dunnarts. Surveys are needed in areas with similar habitat that are less affected by humans, feral species, and frequent burning. There are also changes in the fire regime on the Tiwi Islands. If Butler's Dunnart continues to be unrecorded in the Kimberley, it would mark a substantial decline in the extent of its occurrence and number of known subpopulations. Total numberis likely to be less than 2500 mature individuals. Only ¢.30 individuals have been located on the Tiwi Islands, despite intensive survey work since 1991. Paucity of records might be due in part because conventional trapping techniques are not well suited to Butler's Dunnart (e.g. Elliott traps and even pitfall traps). Exotic predators (domestic and feral cats and possibly domestic dogs), changesto fire regimes, and destruction or degradation of habitat are all likely major threats. Proposals to expand exotic tree plantations on Melville Island are concerns because Butler's Dunnart is not found within existing plantations. Butler’s Dunnart does not occur within any protected areas. A recovery plan was developed for 2004-2008. Recommendations from this plan include: establishing a recovery team, communicating information about Butler’s Dunnart to stakeholders, targeting research to make informed decisions (e.g. toward better survey techniques, total number and distribution, population trends, habitat suitability, and threats), minimizing impact of feral cats, and improving fire management. The recovery plan also recommended further surveys in Kimberley to locate Butler's Dunnart. In Northern Territory, Butler's Dunnart is confined to the Tiwi Islands that are 7481 km?, of which less than 6500 km? are likely suitable for Butler’s Dunnart. About 260 km® of the plausible preferred habitat (open eucalypt woodland) of Butler's Dunnart was cleared and converted to plantations of exotic acacia ( Acacia mangium, Fabaceae ) in 2002-2009. Management of plantations extends into surrounding forest and woodlands, resulting in altered fire regimes, problems in weed control (e.g. African weedy grasses and plantation species) and grazing pressures by feral species.

Bibliography. Archer (1979, 1981a), Baverstock et al. (1984), Blacket, Adams et al. (2001), Blacket, Cooper et al. (2006), Firth et al. (2006), Krajewski et al. (2012), McKnight (2008b), Thomas (1888b), Ward & Woinarski (2012), Woinarski (2004a, 2004b), Woinarski, Brennan et al. (2003), Woinarski, Woolley & Van Dyck (1996), Woolley (2008k).

Figures

56. Kangaroo Island Dunnart (Sminthopsis aitken), 57. Chestnut Dunnart (Sminthopsis archer), 58. Kakadu Dunnart (Sminthopsis bindi), 59. Butler's Dunnart (Sminthopsis butleri), 60. Fat-tailed Dunnart (Smunthopsis crassicaudata), 61. Little Long-tailed Dunnart (Sminthopsis dolichura), 62. Julia Creek Dunnart (Smunthopsis douglasi), 63. Gilbert's Dunnart (Sminthopsis gilbert), 64. White-tailed Dunnart (Sminthopsis granulipes), 65. Grey-bellied Dunnart (Sminthopsis griseoventer), 66. Greater Hairy-footed Dunnart (Smunthopsis hirtipes), 67. White-footed Dunnart (Sminthopsis leucopus), 68. Greater Long-tailed Dunnart (Sminthopsis longicaudata), 69. Stripe-faced Dunnart (Sminthopsis macroura), 70. Common Dunnart (Sminthopsis murina), 71. Ooldea Dunnart (Sminthopsis ooldea), 72. Sandhill Dunnart (Sminthopsis psammophila), 73. Red-cheeked Dunnart (Sminthopsis virginiae), 74. Lesser Hairy-footed Dunnart (Sminthopsis youngsoni)

Distribution. N Australia, where it has a very limited mainland distribution (Kulamburu, Kimberley region) in Western Australia, also on the Tiwi Is (Bathurst and Melville Is) in Northern Australia.