Hemiergis millewae

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Hemiergis millewae
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Scincidae
Genus: Hemiergis
Species:
H. millewae
Binomial name
Hemiergis millewae
Coventry, 1976
H. milliwae range distribution.jpg
The distribution of H. milliwae

The Hemiergis millewae, commonly known as the Millewa skink or Triodia earless skink, is a species of hemiergis lizards that is endemic to Australia. [2] It is a specialist species, highly dependent on Spinifex (Triodia scariosa) for food and shelter, and has only been observed in semi-arid Mallee woodlands of southern and eastern Australia. [3] It is considered endangered throughout parts of its range. [4]

Contents

Description

Hermiergis millewae is a small, terrestrial (ground-dwelling) skink which is native to Australia. It is characterised by dark brown shiny scales with a burnt orange stripe along its back, from above the ear to its hindlimbs, and pale grey underbelly. [5] The Millewa skink has an elongated body, with four short limbs each containing five digits and a long tail similar in length to its torso. [6] As with other Hemiergis (earless) skinks, its ears are not visible and it has an ear depression entirely covered by scales. [3] [5] It has a fifth supralabial scale contacting the eye. [3]

Hermiergis millewae has a snout to vent length of 41-58mm. [3] [5]

Taxonomy

The Millewa skink (Hemiergis millewae) was first identified and described in 1976 by A.J. Coventry. [5] It is one of seven species of earless skinks in the genus Hemiergis, all of which are endemic to Australia. Hemiergis millewae belongs to the family scincidae which is one of the most diverse families of lizards characterized by their small limbs. [7]

Ecology and habitat

Hemiergis millewae is a thigmothermic skink, drawing heat from warm surfaces in its environment in order to regulate its body temperature. [8]

The Millewa skink is one of several specialist species limited to Mallee Eucalypt woodlands in Australia. They have been exclusively observed in areas with large hummocks of Triodia scariosa (Spinifex), hence their other common name Triodia Earless Skink. [9] They are heavily reliant on large clumps of spinifex with surrounding leaf litter which offers a suitable micro-climate and adequate food and protection without which it would be unlikely to survive. [8]

Diet

The Millewa skink is insectivorous.  It depends on the spinifex it inhabits for food, preying primarily on invertebrates which also inhabit hummocks such as ants and termites. [6] [10]

Reproduction

Hermiergis millewae are ovoviviparous, [2] meaning the mother produces eggs which develop inside her and births live young. Female skinks generally birth one to two live young during late summer. [6]

Distribution

The Millewa skink has a fragmented distribution throughout the semi-arid Mallee eucalypt woodlands of southern Australia. There are isolated populations in the Coolgardi bioregion of southern Western Australia, in south-central (Eyre Peninsula and Flinders Ranges) and south-eastern South Australia, and in Victoria where they are limited to the Murray Sunset National Park. [8] Isolated populations have also recently been discovered in the Barrier Range bioregion in north-western New South Wales. [3]

Conservation

Hemiergis millewae is considered a species of 'Least Concern' by the IUCN Red List due to its wide distribution across southern Australia. [11] However, it has been listed as endangered in Victoria owing to its limited distribution and reliance on Triodia scariosa making it susceptible to threats such as land clearing and bushfire. [4] In New South Wales, Triodia scariosa is also listed as a ‘Critically Endangered Ecological Community’ [12] as it only covers 400ha in the Barrier Range where isolated populations of Millewa skink were recently found. [3]

Threats

Land clearing

Approximately 53 per cent of native vegetation has been cleared in the Mallee region to support agriculture, forestry, mining and urban development leading to fragmentation and degradation of Mallee woodlands. [6] In addition, introduced and invasive species such as cattle and feral pigs trample spinifex as well as lizard burrows. This presents a key threat to the Millewa which relies exclusively on Mallee spinifex.

Bushfires

Fires can be beneficial as they promote new spinifex growth, however changes to the frequency and intensity of fires (particularly in southern Australia) alters the nature and distribution of vegetation which lizards depends on for food, shelter and reproduction. [6] The Millewa skink particularly susceptible as it is heavily reliant on large mature spinifex hummocks and leaf litter. Spinifex dwellers typically decline immediately following fires and are most prevalent in areas that experienced fire 19–50 years ago, [10] evidenced by the fact that H. Millewae has not been found in any recently burned areas. [8]

Related Research Articles

<i>Triodia</i> (plant) Genus of plants

Triodia is a large genus of tussock grass endemic to Australia. The species of this genus are known by the common name spinifex, although they are not a part of the coastal genus Spinifex. Many soft-leaved Triodia species were formerly included in the genus Plectrachne. Triodia is known as tjanpi (grass) in central Australia, and have several traditional uses amongst the Aboriginal Australian peoples of the region.

<span class="mw-page-title-main">Southern ningaui</span> Species of marsupial

The southern ningaui is a tiny marsupial carnivore belonging to the Dasyuridae family. Similar in appearance to Ningaui ridei, found throughout central Australia, this species occurs in spinifex on semi-arid sandplains across the southern coast of the continent. The fur is a tawny or greyish olive colour, light grey below, and distinguished by shades of cinnamon. The southern ningaui prefers smaller prey, including insects and spiders, but capable of killing and consuming larger animals such as cockroaches and skinks. Their narrow muzzle is used with quick and fierce bites about the head to despatch their meal. The species was first described in 1983, and placed within the genus Ningaui.

<span class="mw-page-title-main">Geography of Western Australia</span>

Western Australia occupies nearly one third of the Australian continent. Due to the size and the isolation of the state, considerable emphasis has been made of these features; it is the second largest administrative territory in the world, after Yakutia in Russia, despite the fact that Australia is only the sixth largest country in the world by area, and no other regional administrative jurisdiction in the world occupies such a high percentage of a continental land mass. It is also the only first level administrative subdivision to occupy the entire continental coastline in one cardinal direction.

<span class="mw-page-title-main">Striated grasswren</span> Species of bird

The striated grasswren is a small, cryptically coloured ground-dwelling species of wren-like bird in the family Maluridae, endemic to Australia. It occupies a large discontinuous range across arid and semi-arid areas of western, central and southern Australia where it is associated with spinifex (Triodia) grass.

<span class="mw-page-title-main">Mallee emu-wren</span> Species of bird

The mallee emu-wren is a species of bird in the Australasian wren family, Maluridae. It is endemic to Australia.

<span class="mw-page-title-main">Mallee Woodlands and Shrublands</span>

Mallee Woodlands and Shrublands is one of 32 Major Vegetation Groups defined by the Australian Government Department of the Environment and Energy.

<span class="mw-page-title-main">Murray Darling Depression</span>

The Murray Darling Depression , also known as the Murray-Darling woodlands and mallee, is a 19,717,651 HA biogeographic region and an ecoregion in southeastern Australia consisting of a wooded plain through which flow two of Australia's biggest rivers, the Murray and the Darling. There are several modern human settlements in the bioregion including Ivanhoe and Manilla, but the region also contains some of the oldest known human occupation sites in Australia.

<span class="mw-page-title-main">Four-toed earless skink</span> Species of lizard

The four-toed earless skink, also known commonly as Péron's earless skink, the lowlands earless skink, or the four-toed mulch skink, is a viviparous earless skink endemic to southern Australia.

<i>Cryptoblepharus australis</i> Species of lizard

Cryptoblepharus australis, commonly called the inland snake-eyed skink, is a species of skink in the genus Cryptoblepharus.

<span class="mw-page-title-main">Centralian blue-tongued skink</span> Species of lizard

The Centralian blue-tongued skink or Centralian blue-tongue is a species of skink, occurring predominantly in the far north-west corner of New South Wales, Australia. It is one of six species belonging to the genus Tiliqua; the blue-tongued skinks and the shinglebacks.

<i>Strophurus elderi</i> Species of lizard

Strophurus elderi, also known commonly as the jewelled gecko, is a terrestrial, nocturnal species of gecko, a lizard in the family Diplodactylidae. Previously classified within the genus Diplodactylus, S. elderi is one of 22 geckos belonging to the genus Strophurus. The species is endemic to the arid regions of central and north-western Australia.

<span class="mw-page-title-main">Mallee military dragon</span> Species of lizard

The Mallee military dragon, also commonly known as the Mallee dragon and the Mallee sand-dragon, is a species of lizard in the family Agamidae. The species is native to the arid parts of southern Australia.

<i>Triodia scariosa</i> Species of plant

Triodia scariosa, is more commonly known as porcupine grass or spinifex, and belongs to the endemic Australian grass genusTriodia. The species is perennial and evergreen and individuals grow in mounds, called hummocks, that reach up to ~1m in height. The leaves are ~30 cm long, 1mm in diameter, needlepointed and rigid, and its inflorescence is a narrow, loose panicle that forms a flowering stalk up to ~2m in height. The name is derived from Latin; Triodia refers to the three-toothed lobes of the lemma, and scariosa is in reference to the thin, dry glume. The species is common to Mallee (MVG14) and Hummock grassland (MVG20) communities, in arid and semi-arid regions of Australia.

<span class="mw-page-title-main">Marble-faced delma</span> Species of legless lizard endemic to Australia

The Delma australis is often known as the southern legless lizard, or the marble-faced delma. This terrestrial lizard falls into the category of slender Pygopodidae, a legless lizard. There are 21 known species in the Pygopdidae family in Australia. Marble-faced delmas are endemic to Australia. Delma australis was first described by Kluge in 1974.

<i>Morethia obscura</i> Species of lizard

The shrubland Morethia skink is a species of skink endemic to Australia, of the family Scincidae, found in New South Wales, South Australia, Victoria (Australia), Western Australia in Australia.

The Southern Mallee ctenotus is a medium sized lizard in the family scincidae (skink) found in the central and southern interior regions of South Australia and Western Australia; the Mallee regions of NSW and Victoria, in Australia.

<i>Ctenotus brooksi</i> Species of lizard

Ctenotus brooksi, also known commonly as Brooks' wedge-snouted ctenotus, the wedgesnout ctenotus, and the sandhill ctenotus, is a species of skink, a lizard in the family Scincidae. The species is endemic to Australia and found in semi-arid regions.

<i>Ctenotus schomburgkii</i> Species of lizard

The barred wedge-snout ctenotus is a species of skink found in Australia.[2]

<i>Lerista timida</i> Australian species of skink

Lerista timida, the dwarf three-toed slider or wood mulch-slider, is a species of skink found in Australia. Other common names for the species include timid slider and dwarf burrowing skink. The skink is a member of the Lerista genus which are confined to continental Australia and are mostly a burrowing species of skink. The genus consists of consists elongated, smooth-scaled, Fossorial lizards that are specialized for life in the upper soils and dry leaf litter through which they slide using Lateral undulation as a form of locomotive action, giving rise to their nickname as sliders. They normally emerge of a night-time to hunt for small Invertebrates such as ants, termites and insects. If disturbed, they dive immediately into any loose substrate to avoid predation, this behavior leaves behind a distinctive disrupted wavy track that often found on sandy flats or dunes, roads and tracks.

The yellow-tailed plain slider is a species of skink located primarily in the desert areas of South Australia, Western Australia, Northern Territory and New South Wales in Australia. This uncommon lizard can be identified by its bright yellow tail, and is usually found buried under loose soil, tree stumps and leaf litter.

References

  1. Shea, G.; Cogger, H. (2017). "Hemiergis millewae". IUCN Red List of Threatened Species . 2017: e.T109472762A109472767. doi: 10.2305/IUCN.UK.2017-3.RLTS.T109472762A109472767.en . Retrieved 18 November 2021.
  2. 1 2 Hemiergis millewae at the Reptarium.cz Reptile Database . Accessed 22 March 2015.
  3. 1 2 3 4 5 6 Farquhar, J.E. (2020). "Range extension of the Triodia Earless Skink Hemiergis millewae, and first record in New South Wales". Australian Zoologist. 40 (4): 636–640. doi:10.7882/AZ.2019.022. S2CID   199106464.
  4. 1 2 "Flora and Fauna Guarantee Act 1988 (Vic) - Threatened List". September 2022.
  5. 1 2 3 4 Coventry, A.J. (1976). "A new species of Hemiergis (Scincidae: Lygosominae) from Victoria" (PDF). Memoirs of the National Museum of Victoria. 37: 23–26. doi:10.24199/j.mmv.1976.37.02.
  6. 1 2 3 4 5 Mallee Catchment Management Authority (2013). "Mallee Lizards Field Guide" (PDF).{{cite journal}}: Cite journal requires |journal= (help)
  7. Vitt, L (Oct 2018). "Skink". Encyclopædia Britannica.
  8. 1 2 3 4 Nimmo D.G., Spence-Bailey L.M., Kenny S. (2008). "Range extension of the Millewa Skink Hemiergis millewae in the Murray-Sunset National Park, Victoria". The Victorian Naturalist. 125: 110–113.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. Canessa, Stefano; Heard, Geoffrey W.; Robertson, Peter; Sluiter, Ian R. K. (2015). "Dealing with Trade-Offs in Destructive Sampling Designs for Occupancy Surveys". PLOS ONE. 10 (3): e0120340. Bibcode:2015PLoSO..1020340C. doi: 10.1371/journal.pone.0120340 . PMC   4356509 . PMID   25760868.
  10. 1 2 "Fire and Wildlife in the Mallee" (PDF). 2010.
  11. Shea, G. & Cogger, H. (2017). "Hemiergis millewae. The IUCN Red List of Threatened Species 2017". doi: 10.2305/IUCN.UK.2017-3.RLTS.T109472762A109472767.en .{{cite journal}}: Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link)
  12. NSW Government (2016). "Biodiversity Conservation Act 2016 (NSW) - Schedule 2".