Northern hopping-mouse
N. aquilo at Wurruwarrkbadenumanja, Groote Eylandt
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Muridae
Genus: Notomys
Species:
N. aquilo
Binomial name
Notomys aquilo
Thomas, 1921
Notomys aquilo range 2019 [1]

The northern hopping-mouse (Notomys aquilo) is an Australian rodent in the Family Muridae. It was described as a new species by the British zoologist Oldfield Thomas in his 1921 publication on Australian 'jerboa-rats' 54 years after the deposition of the male type specimen labelled 'Cape York' in the British Museum of Natural History. [2] The specific name aquilo translates from the latin as 'north', for the northern distribution of the species. N. aquilo occurs in forest and woodland habitats and coastal beach dunes in northern Australia. [3] Notomys aqulio formerly occurred in eastern Arnhemland and possibly Cape York Peninsula, however in 2019 the species appeared to be restricted to Groote Eylandt in the western Gulf of Carpentaria. [1] Notomys aquilo is the only known extant species in the genus Notomys that does not occur in arid or semi-arid regions of the Australian continent. [4]



Discovery, Indigenous Knowledge and Taxonomy

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Notomys aquilo is known to the indigenous peoples of eastern Arnhemland and Groote Eylandt, with traditional knowledge of the species noting that it moves around by jumping, is nocturnal and returns to its hole in the ground early in the morning. [5] In some areas of its current or former range there is a specific name for Notomys aquilo, including dayhdayh in the Kune/Mayali and Kundedjnjenghmi language groups of north-east Arnhemland. [5] Other language groups refer to N. aquilo using a generic term for small rodents and dasyurids, including wurrendinda in the Anindilyakwa language of Groote Eylandt [6] and djirrkin, wara, hudinwara, nik-nik (Nhulunbuy, Blue Mud Bay), kidjikidjidayhdayh (Maningrida, Dalabon language) and kilki (Cadell River area) in other parts of Arhnemland [7][8][9]

In the indigenous taxonomy of Groote Eylandt, Notomys aquilo included in the akwalya (all living things) > yinungungwangba-murriya (four-footed terrestrial animals) > wurrendinda (rats, mice and small dasyurids/planigales). [5] [10]

The earliest record of Notomys aquilo in a European collection is the type specimen held by the British Museum labelled as 'Cape York', although the precise collection date and location is unknown. [2] The Australian anthropologist and biologist Donald Thomson was the next to collect specimens in 1942 and 1944 on the south-west coast of Groote Eylandt, where he reported capturing large numbers on coastal dunes once the nature of the burrows had been determined. [7] Thomson made extensive notes on the ecology of Notomys aquilo based on his observations in the field on Groote Eylandt and of a captured colony, which he returned alive to his home in Victoria [7] Thompson also reported observations Notomys aquilo provided by an informant residing at Umbakumba, who described them as abundant in sandy ground among tussocks of grass around Little Lagoon. [7] The next collection of the Notomys aquilo was during the American–Australian Scientific Expedition to Arnhem Land in May to July 1948, when specimens were obtained in dunes surrounding the expedition camp at Umbakumba. [11] These specimens were later described as Notomys carpentarius, a species that is invalid based on Oldfield Thomas' earlier description of the species. [12] Johnson [12] obtained all hopping-mouse specimens by excavating burrows and had no success in using standard traps. He provided notes on the habitat and burrow structure of Notomys aquilo in the Umbakumba area. [12]

The Notomys genus is located in the Pseuduomys division of the subfamily Murinae. [4] Rodents within this group are known as the Australian old endemic rodents with an original ancestor that evolved in south-east Asia around 25 million years ago and colonised areas west of Wallace's Line between 15 and 20 million years before present. [4] As fossil evidence indicates that there were no rodent species present on the Australian continental land mass when it split from Antarctica 55 million years ago, the original ancestors of the modern Australasian rodents are assumed to have crossed Wallace's line and then colonised Australia and New Guinea as the Australian plate moved north to intersect the Asian plate. [4] 5 to 10 million years before present, as Australia and New Guinea became increasingly closer to the eastern Indonesian archipelago, at least four groups of rodents colonised the large land masses on the Australian continental plate. [4] A period of rapid speciation followed, leading to modern Australian 'old endemic' groups including the water rats (Hydromys, Xeromys), prehensile-taied rats (Pogonomys), mosaic-tailed rats (Melomys, Uromys), stick-nest rats (Leporillus), hopping-mice (Notomys), rock rats (Zyzomys), rabbit-rats (Conilurus), tree rats (Mesembriomys), short-tailed mice (Leggadina), broad-toothed rats (Mastacomys) and pseudo-mice (Pseudomys). [4] These groups are not closely related to the relatively recently arrived true rats in the genus Rattus. [4]

Description

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Notomys aquilo have elongated hind legs, a reduced number of sole-pads on the hind feet, large eyes, a hopping gait and long tail with a tufted tip, characters that are typical of the genus Notomys. [4] N. aquilo has a glandular area or pouch on the throat in both genders, a characteristic also present in closely related species within the Notomys, including the spinifex hopping-mouse and dusky hopping-mouse. [4] This structure is not used

Notomys aquilo is pale sandy-brown above and white below, with fine hair, flesh-colored thinly-haired feet feet and a well marked neck gland noted in the (male) type specimen. [2] In one study on Groote Eylandt, adult female northern hopping-mice (n=13) weighed between 30 g (1.1 oz) and 50 g (1.8 oz) (mean 40 g (1.4 oz)) and adult males (n=12) weighed 23 g (0.81 oz) to 37 g (1.3 oz) (mean 32 g (1.1 oz)). [3] Head and body lengths range from a mean of 94 mm (3.7 in) (s.d. 5.3 mm (0.21 in)) for adult females and a mean of 89 mm (3.5 in) (s.d. 5.9 mm (0.23 in)) for adult males. [3] Tail lengths range from a median of 165 mm (6.5 in) for adult females and 156 mm (6.1 in) for adult males. [3]

In common with other Australian hopping-mice, Notomys aquilo shares a marked morphological similarity to arid adapted 'hopping' rodents in several unrelated families or genera from other parts of the world, including the kangaroo rats (Dipodomys) of the deserts of North America and the jerboas (Jaculus), jirds (Meriones) and gerbils (Gerbillus) of the arid regions of Africa and central Asia, a striking example of convergent evolution. [4] The evolution of the hopping gait across a several unrelated rodent genera is thought to have been driven by efficiencies in escaping predators due to enabling faster and more eratic evasion, particularly in the presence of night hunting birds such as owls. [4] Hopping gaits have also been shown to require less energy than quadrapedal locomotion at high speeds. [4]

Range and distribution

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Based on recent surveys and records, the northern hopping-mouse is restricted to Groote Eylandt in the western Gulf of Carpentaria. [1] There are only two specimen based records from the mainland, including the 1973 specimens from the Upper Cadell River at Kolobirrahda and the type specimen labelled 'Cape York' dated around 1867 [8]. While other sightings from the mainland are based on tracks and burrows, records based on burrows that pre-date 2010 are in doubt due to the discovery that delicate mice (Pseudomys delicatulus) make a similar but smaller burrow in eastern Arnhem Land. [13] Records from tracks on the mainland also need to be treated with caution due to confusion with other species, including birds, particularly in soft sand and when tracks have weathered. [8] None of the mainland records are located within Conservation Reserves or National Parks, although most existing records, including all Groote Eylandt sites, are within Indigenous Protected Areas. [1] While there has been some debate regarding the origin of the type specimen, the absence of confirmed records from Cape York should not be taken to demonstrate its absence there. [8] The former and contemporary range distribution of the northern hopping-mouse occurs on the margins of the Gulf of Carpentaria, indicating that the species may have formerly occurred across broad areas of the now inundated Carpentarian Basin. [14][8]

Habitat

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Typical coastal dunefield habitat, Groote Eylandt.

Donald Thomson was the first biologist to observe the habitat of Notomys aqulio, describing the species as inhabiting the sandhill-sandy stretch between the high tide mark and the 'dry jungle' belt that is common in coastal areas of Groote Eylandt. [7] Johnson encountered Notomys aquilo in similar coastal habitat on Groote Eylandt, with numerous tracks and burrows observed in wind blown dunes and sand flats adjacent to the coast at Umbakumba. [11] Museum labels appended to specimens obtained from the Upper Cadell River at Kolobirrahda in 1973 included habitat notes from the collection site, described as sandy, stony country near rocks and water. [1] While the Cadell River site was the first Notomys aqulio specimen collected at an inland open forest site, further evidence of occupation at non-coastal open forest and woodland sites was later obtained from Groote Eylandt, initially at Enungwadena (Kings Crossing). [15] Habitats in both coastal and inland areas are characterised by sandy substrates. [15]

Behaviour and Ecology

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Burrowing behaviour

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Burrowing behavior of Notomys aqulio is similar to that of other Notomys species, with burrows constructed by excavating a descending drive three to five meters long, and then constructing vertical shafts from below, with the original drive back to the excavated material (spoil) closed for most of its length. [4] The burrow system is subsequently accessed via several vertical 'pop holes' that are located some distance from the pile of sand resulting from the excavation; predators attracted to the burrow spoil have difficulty detecting and accessing the burrow. [4] The burrowing behaviour of Notomys aquilo was first described by Donald Thomson based on burrows excavated in 1943 on south-west Groote Eylandt, [7] with a further description made by Johnson based on data from the 1948 expedition to Umbakumba. [11] Thompson described a 200 cm (79 in) or occasionally longer tunnel attached to several 50 mm (2.0 in) diameter pop holes with shafts descending vertically for 45 cm (18 in), with no spoil material around the pop hole. [7] The spoil was generally located a few feet away as a pile of lighter sand with no obvious burrow visible. [7] Johnson [11] excavated several burrows at Umbakumba, including one with an elliptical main tunnel 167 cm (66 in) long and 6.3 cm (2.5 in) wide reaching a depth of 106 cm (42 in). The burrow system was accessed by three pop holes connected to vertical shafts approximately 31 mm (1.2 in) in diameter, and the terminal section of the original tunnel adjacent to the spoil was back-filled and sealed with grey surface sand. [11]

Home range

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The

Foraging and diet

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The diet of Notomys aquilo is poorly known, although is presumed to be similar to that of other species in the genus Notomys, which feed mostly seeds with a percentage of green plant material and insects. [4]

Reproduction

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Information on the reproduction of Notomys aquilo is limited. Johnson collected immature mice in mid-June (1948) and two females collected in the same month were carrying four and five uterine foetuses. [12] Commonly give birth to three but occasionally four young and females have four mammae. [7] At birth the young are hairless and blind, with a very deep pink colouration and measure approximately 52 mm (2.0 in) with the tail measuring 23 mm (0.91 in). [7] Juveniles are fully clothed with hair at day fifteen and eyes open at day twenty-two. [7]

Vocalisations

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Hopping-mice in the genus Notomys have well developed vocal communication. [4] Donald Thomson [7] described the vocalisations of his captive population of Notomys aquilo, with the adult cry described as a "bird-like" twitter and young individuals making a squeaky, shrill sound. These social vocalisations were identified by Thompson as being distinct from those made by animals in distress, which he described as a distinct sharp, shrill and raspy squeal. [7]

Conservation status and threats

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IUCN assessment and legislative status

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The IUCN (2015) has assessed the Australian hopping-mouse as endangered B1ab(ii,iii,v). [16] N. aquilo is listed as an endangered species under the Commonwealth EPBC Act 1999, [17] vulnerable in Queensland [18] and vulnerable in the Northern Territory.[19] The Action Plan for Australian Mammals 2012 assessed the status of Notomys aquilo as vulnerable A2be+3be+4be. [20]

Population status

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Notomys aquilo appears to be in decline, with no recent confirmed records on the mainland, the last confirmed sighting being specimens collected in Arnhemland in 1973. Recent records of Notomys aquilo are all located within the Anindilyakwa Indigenous Protected Area (Groote Eylandt). If extant mainland populations cannot be located, Groote Eylandt is likely to represent the last refuge area for Notmomys aquilo populations. Habitats on the island have potentially been less impacted by fire regime changes, disturbance from pastoralism, feral animals and decline of prey species that has been documented at mainland locations where Notomys aquilo was known or considered likely to occur.

Threats

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Identified and potential threats to populations of Notomys aquilo are related to the direct and indirect actions of humans (Homo sapiens), including land clearing, altered fire regimes, stocking with exotic ruminants, proliferation of feral animals including feral cats and potentially atmospheric pollution leading to global heating and rising sea levels.

The main threat to Notomys aquilo populations is thought to be the decline in habitat structure linked to damage from feral and stocked herbivores, more frequent and extensive fires and predation by feral cats [21], exacerbated in some places weed encroachment. [22] Mining exploration licences and active mining titles cover broad areas of the range of Notomys aquilo, including most of Groote Eylandt and adjacent islands and large areas of north-eastern Arnhemland.

Conservation reserves

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Notomys aquilo has not been detected within gazetted Government national parks or private conservation reserves, [1] although subfossil remains have been recorded within Kakadu National Park. [23] All recent confirmed records are from the Anindilyakwa Indigenous Protected Area on Groote Eylandt. [1] There are historical specimen based records (1974) from one location on the mainland within the Jelk Indigenous Protected Area in north-eastern Arnhemland. [1] There are historical non-specimen based (unconfirmed) records from several other Indigenous Protected Areas in eastern Arnhemland, including the Dhimurru IPA, Jelk/Warddeken IPA and South-east Arnhemland IPA . [1]

References

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  1. ^ a b c d e f g h i "Northern Hopping-mouse Notomys aquilo". Atlas of Living Australia. Retrieved 30 December 2020.
  2. ^ a b c Thomas, Oldfield (1921). "Notes on the species of Notomys, the Australian Jerboa-rats". Annals and Magazine of Natural History. 9 (8, 47): 536–541. doi:10.1080/00222932108632614.
  3. ^ a b c d Diete, R; Meek, P; Dickman, C. R.; Leung, L (2016). "Ecology and conservation of the northern hopping-mouse (Notomys aquilo)". Australian Journal of Zoology. 64: 21–32.
  4. ^ a b c d e f g h i j k l m n o p Watts, C. H. S.; Aslin, H. J. (1981). The Rodents of Australia. Australia: Robertson Publishers.
  5. ^ a b c National Environmental Research Program, Bininj Kunwok Language Project. "Northern Hopping Mouse Notomys aquilo". Bininj Kunwok Names for Plants and Animals. Retrieved 30 November 2020.
  6. ^ Groote Eylandt Linguistics (1993). Eningerribirra­-langwa jurra Groote Eylandt Linguistics-langwa. Angurugu, Groote Eylandt: Groote Eylandt Linguistics. {{cite book}}: soft hyphen character in |title= at position 15 (help)
  7. ^ a b c d e f g h i j k l m Dixon, J; Huxley, L, eds. (1985). Donald Thomson's Mammals and Fishes of Northern Australia. Melbourne Australia: Nelson.
  8. ^ a b c d e Woinarski, J.C.Z; Gambold, N; Wurst, D; Flannery, T.F.; Smith, A.P.; Chatto, R.; Fisher, A. (1999). "Distribution and habitat of the Northern Hopping Mouse Notomys aquilo". Wildlife Research. 26: 495–511.
  9. ^ Woinarski, J.C.Z. (2004). National Multi-species Recovery Plan for the Carpentarian Antechinus Pseudantechinus mimulus, Butler’s Dunnart Sminthopsis butleri and Northern Hopping-mouse Notomys aquilo, 2004 - 2009. Darwin, Northern Territory: Department of Infrastructure Planning and Environment.
  10. ^ Waddy, Julie (1982). "Biological Classification from a Groote Eylandt Aborigine's Point of View". Journal of Ethnobiology. 2 (1): 63–77.
  11. ^ a b c d e Johnson, D. H. (1964). "Mammals of the Arnhem Land expedition". Records of the American–Australian Scientific Expedition to Arnhem Land. 4: 427–515.
  12. ^ a b c d Johnson, D. H. (1959). "Four new mammals from the Northern Territory of Australia". Proceedings of the Biological Society of Washington. 72: 183–187.
  13. ^ Diete, R. L.; Adamczyk, S. M.; Meek, P. D.; Dickman, C. R.; Leung, L. K.-P. (2015). "Burrowing behaviour of the delicate mouse (Pseudomys delicatulus) and the management implications for a threatened sympatric rodent (Notomys aquilo)". Australian Mammalogy. 37: 260–263.
  14. ^ Schulmeister, J. (1992). "A holocene pollen record from lowland tropical Australia". The Holocene. 2: 107–116.
  15. ^ a b Woinarski, J; Ward, S. "Threatened Species of the Northern Territory - Northern Hopping-mouse Notomys aquilo 2012" (PDF). Northern Territory Government. Retrieved 5 January 2021.
  16. ^ Red List, IUCN. "Notomys aquilo. The IUCN Red List of Threatened Species 2015: e.T62172196A132190206". IUCN Red List. IUCN. Retrieved 30 December 2020.
  17. ^ [1], Department of Agriculture, Water and the Environment (2020). Notomys aquilo – Northern Hopping-mouse. Species Profile and Threats Database. Commonwealth of Australia, Canberra (accessed 1 January 2020)
  18. ^ "Queensland Nature Conservation (Animals) Regulation 2020 Subordinate Legislation 2020 No.136". Queensland Government.
  19. ^ [2], Northern Territory Government (2015). Territory Parks and Wildlife Conservation Act 2000. As in force at 13 November 2014 (accessed 26 February 2016).
  20. ^ Woinarski, J. C. Z.; Burbidge, A. A.; Harrison, P. L. (2014). The Action Plan for Australian Mammals 2012. Melbourne: CSIRO Publishing.
  21. ^ Leahy, L.; Legge, S. M.; Tuft, K; McGregor, H. W.; Bartuma, L.A.; Jones, M.E.; Johnson, C. N. (2016). "Amplified predation after fire suppresses rodent populations in Australia's tropical savannas". Wildlife Research. 48 (2): 705–716. doi:10.1071/WR15011.
  22. ^ Legge, S; Smith, J. G.; James, A; Tuft, K. D.; Webb, T; Woinarski, J. C. (2019). "Interactions among threats affect conservation management outcomes: Livestock grazing removes the benefits of fire management for small mammals in Australian tropical savannas". Conservation Science and Practice. 1 (7): 52.
  23. ^ Foley, D (1987). "Faunal Analysis of Angbangbang 1 and Djuwarr 1". In Jones, R (ed.). Archaeological Research in Kakadu National Park. Canberra: Australian National Parks and Wildlife Service. pp. 97–102.
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  • Commonwealth Department of the Environment Species Profile and Threats Database - Northern Hopping-mouse [3]
  • Northern Territory Department of Land Resource Management Threatened Species of the Northern Territory Profiles - Northern Hopping-mouse [4]
  • Australian Geographic - Northern Hopping-mouse caught on camera [5]