Sminthopsis gilbert, Kitchener, Stoddart & Henry, 1984

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 : 340

63.

Gilbert's Dunnart

Sminthopsis gilbert

French: Dunnart de Gilbert / German: Gilberts SchmalfuRbeutelmaus / Spanish: Raton marsupial de Gilbert

Taxonomy. Sminthopsis gilberti Kitchener, Stoddart & Henry, 1984 ,

Mt. Saddleback , 32° 58’ S, 116° 20° E, Western Australia, Australia.

The tribe Sminthopsinae (today containing 28 species across four genera) has been the subject of numerous morphological and molecular investigations. Interestingly, a recent genetic phylogeny failed to support monophyly of the genus Sminthopsis with respect to Antechinomys and Ningaui . There were three deeply divergent clades of Sminthopsis resolved in the phylogeny. In the first, S. longicaudata was sister to A. laniger . The second clade was composed of the traditional morphologically based Macroura Group: five Sminthopsis comprised a strongly supported clade that included S. crassicaudata, S. bind, S. macroura , S. douglasi , and S. virginiae . This clade of five dunnarts was in turn 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 Ningaw: was itself positioned as a poorly supported sister to a well-supported 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. archer: with a clade containing five species: S. murina , S. gilberti, S. leucopus , S. butleri , and S. dolichura . In his landmark revision of dunnarts, M. Archer considered variation to be clinal and synonymized S. murina albipes , S. murina fuliginosa , and S. murina tater with S. murina . Nevertheless, he noted that use of these names was not necessarily to be interpreted as recognition of their subspecific status. M. Archer believed that S. murina “fuliginosa” occupied Western Australia and South Australia west of the Flinders Range; the typo-typical form was to the east ofthis range up to c.28° S; S. murina “tater” was evidently restricted to north-eastern Queensland; and a fourth form, allied to S. murina “fuliginosa,” occupied Kangaroo Island, South Australia. Archer did not recognize S. murina albipes as distinct from the typical form. Upon further inspection and with more comparative specimens, collections from south-western Western Australia raised the possibility that some morphological variation noted by Archer (e.g. body size, presence or absence of cusps on various teeth, and molar row lengths) was not clinal but was indicative of separate species. D. J. Kitchener and colleagues in 1984 redefined S. murina and described four new species: S. dolichura , S. gilberti, S. griseoventer , and S. aitkeni . Concurrent research by P. R. Baverstock and colleagues in 1984 strengthened these revisions on genetic (allozyme) grounds. In the most recent direct (mtDNA and nDNA) sequencing work, phylogenetically, S. gilbert was strongly supported assister to S. murina . These two species were in turn well supported as sister to a clade containing S. leucopus , S. butler , and S. dolichura . S. gilbert was named after J. Gilbert who collected extensively in the south-western Western Australia in 1843-1844. Monotypic.

Distribution. SW Australia, restricted to S Western Australia, in a band from the Darling scarp near Perth, across the C & S Wheatbelt region, and outlying populations on the Roe Plain, S of the Nullarbor Plain.

Descriptive notes. Head-body 8.1-9.2 cm,tail 7.5-9.2 cm; weight 14-25 g. Externally, Gilbert’s Dunnart is very similar to the Little Long-tailed Dunnart (S. dolichura ) and the Grey-bellied Dunnart (S. griseoventer ), but it tends to be larger. Fur color of Gilbert's Dunnart is pale gray above (similar to the Little Long-tailed Dunnart), but its hindfoot is longer than in Little Long-tailed Dunnarts and Grey-bellied Dunnarts (17-5-19 mm vs. 16-8-17-5 mm). Ears of Gilbert’s Dunnart are longer than the Little Long-tailed Dunnarts and Grey-bellied Dunnarts (21-1 mm vs. 17-7-19-3 mm). Gilbert’s Dunnart has whiter ventral fur than the Grey-bellied Dunnart. Tail of Gilbert’s Dunnart is shorter than head-body length, except for the Roe Plain populations. There is a distinctive patch of white fur behind ear.

Habitat. In the west, mixed eucalypt woodlands on sandy loam soils; in central and southern Wheatbelt, Casuarina (Casuarinaceae) shrublands or mallee-heaths on gravelly soils; and farther east, mallee shrublands on sand plains (Frank Hann National Park, Lake Cronin, and Roe Plain) and open woodlands of salmon gum ( Eucalyptus salmonophloia, Myrtaceae ) or giant mallee (E. oleosa) on loamysoils. Kitchener and colleagues in 1984 provided detailed descriptions of habitats for this species,as follows: Gilbert’s Dunnart is found in the near coastal ranges and parts of the Wheatbelt of southwest Western Australia. The species appears to favor heathlands on generally ‘heavy’ soils, although it has also been captured in eucalypt woodlands and mallee, albeit typically with a heath understrata. In the Darling Range, Gilbert’s Dunnart occurs 593 m above sea level in myrtaceous heaths, dominated by Macrozamia riedlei ( Zamiaceae ), Calothamnus quadrifidus ( Myrtaceae ) and Xanthorrhoea preissii ( Xanthorrhoeaceae ), on shallow granites with high clay content, and strewn with small, angular granitic rocks. Butit is also found on lower slopes incorporating the dominant proteaceous heath elements: Dryandra carduacea, Petrophilespp., and Leptospermum sp. (Myrtaceae) , on granites which have surface scree of pebbles. The type locality of Gilbert’s Dunnart is at the base of the ranges (240 m above sea level) in a small gully with a seasonal creek. This area is vegetated with open woodland of Eucalyptus wandoo and E. calophylla with occasional E. marginata also present; there is a sparse, 2 m high, shrub layer of X. preissii and Acacia extensa ( Fabaceae ) and a mixed, lower than 1 m high, shrub layer above light-brown sandy loam soil with some pisolitic gravel. In the central and southern Wheat Belt, this species is found in open shrub mallee of Eucalyptus eremophila and occasional E. foecunda over a moderately dense heath reaching 2 m in height of Melaleuca uncinata ( Myrtaceae ), M. spathulata and Hakea lissocarpha ( Proteaceae ) above low sedges on sandy loam soil. Gilbert's Dunnart can also be found in open heaths dominated by Casuarina campestris on gravelly and coarse, sandy soils. At the eastern edge of the southern Wheat Belt, at Lake Cronin, Gilbert’s Dunnart occurs in open woodlands of Salmon Gum, E. salmonophloia, over sparse shrubs including Exocarpos spp. (Santalaceae) and Acacia spp. , on heavy, red-brown soil. It is also found in moderately dense, 5 m high, regenerating mallee on heavy red-brown loams. There are no records from the South-west Interzone. Gilbert's Dunnart is allopatric with the Little Long-tailed Dunnart in the eastern Jarrah Forest and across the central Wheatbelt at about 32° S latitude, and is also allopatric with the Grey-bellied Dunnart, which occurs to the west and south.

Food and Feeding. There is no specific information available for this species, but Gilbert’s Dunnart is mostlikely insectivorous.

Breeding. Throughout the distribution of Gilbert's Dunnart, breeding occurs in spring to early summer. Pouch young are present in October-November, and juveniles are found in the population in February. Pouches contain eight teats; one female captured in October on the Roe Plain had seven hairless young attached. Adult males were still present in the population after they were mated. Gilbert's Dunnart probably nests above ground in logs or vegetation.

Activity patterns. There is no specific information available for this species, but Gilbert’s Dunnart is most likely nocturnal.

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

Status and Conservation. Classified as Least Concern on The IUCN Red List. Gilbert's Dunnart has a wide distribution, presumably has a large overall population, occurs in a number of protected areas, and does not face any major conservation threats. Gilbert’s Dunnart was one of the most common species recorded during a 2000-2002 survey in the Wheatbelt. Salinity and rising water tables caused by land degradation (an unfortunate feature of the Western Australian Wheatbelt) is a threat to remnant habitat. Gilbert’s Dunnart has been recorded from several protected areas including Tutanning, Dragon Rocks and Nuytsland nature reserves.

Bibliography. Archer (1981a), Baverstock et al. (1984), Blacket, Adams et al. (2001), Blacket, Cooper et al. (2006), Burbidge et al. (2004), How et al. (1988), Keighery et al. (2004), Kitchener et al. (1984), Krajewski et al. (2012), McKenzie (2008a), McKenzie & Robinson (1987), Morris & McKenzie (2008), Thomas (1888b).

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. SW Australia, restricted to S Western Australia, in a band from the Darling scarp near Perth, across the C & S Wheatbelt region, and outlying populations on the Roe Plain, S of the Nullarbor Plain.