Striped legless lizard (Delma impar)

Description

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Striped legless lizard fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Striped legless lizard description

Legless lizards, sometimes referred to as ‘snake-lizards’ ⁽⁵⁾, closely resemble snakes but are distinguishable by the visible ear openings and by greatly reduced hind limbs, which are visible as small flaps ⁽⁶⁾. A cryptic and difficult to identify species ⁽³⁾, the striped legless lizard varies in colour ⁽⁷⁾, but is typically light brown with dark brown or blackish stripes running the length of the body ^{(6) (7) (8)}, although, these stripes can be pale or even absent in some individuals ⁽⁹⁾. The underside is generally white, cream or pinkish in colour ⁽⁸⁾, and the head is slightly darker than the body ⁽¹⁰⁾.

The striped legless lizard is very slender, only slightly thicker than a pencil ⁽⁶⁾, with a tail twice the length of the body ⁽²⁾. The tip or whole length of the tail can be voluntarily shed to escape predators ^{(7) (11)}, and when distressed, this lizard can also emit a high-pitched squeak ⁽¹²⁾. Male and female striped legless lizards are almost identical in appearance; however, the male may have small ‘spurs’ under each hind limb flap ⁽²⁾. Hatchlings lack the distinctive stripes of adults, but have a characteristic dark brown or black head which may be intended to deter predators by mimicking the highly poisonous eastern brown snake (Pseudonaja textilis) ⁽¹¹⁾.

Size

Total length: 30 cm ⁽²⁾

Adult snout-vent length: 9 – 12 cm ^{(2) (3)}

Hatchling snout-vent length: 4 – 4.5 cm ⁽⁴⁾

Adult weight: 3.0 - 6.9 g ⁽²⁾

Hatchling weight: 0.5 - 0.75 g ⁽⁴⁾

Striped legless lizard biology

Little is known about the striped legless lizard’s biology ⁽⁸⁾. It is thought to prey selectively on invertebrates measuring one to three centimetres in length ^{(7) (8) (15)}, such as caterpillars ⁽⁷⁾, spiders and crickets ⁽¹³⁾, and its predators are assumed to include snakes, raptors, and other lizards ⁽²⁾. While it is believed to be diurnal ⁽⁶⁾, moving up to 20 metres in one day ⁽²⁾, the striped legless lizard is often under cover ⁽⁶⁾(2), and rarely basks in open areas ⁽¹²⁾.

The average lifespan of this species is estimated at ten years, with males reaching sexual maturity at two to three years and females at three to four years ⁽²⁾. Little is known about reproduction other than that two eggs are laid in December or January and hatch 35 to 60 days later ⁽²⁾. This lizard appears most active in November and December, a pattern believed to be related to reproductive activity ⁽⁴⁾. The rest of the winter is thought to be spent underground or beneath rocks and logs ⁽⁹⁾.

Striped legless lizard range

The striped legless lizard is endemic to south-eastern Australia ^{(5) (13)}, where it occurs in Victoria, the Australian Capital Territory and parts of New South Wales ⁽¹³⁾. Its distribution is patchy and poorly documented ^{(4) (5) (6)}, but substantial range contraction is believed to have occurred over the past 100 years ⁽⁸⁾.

Striped legless lizard habitat

The striped legless lizard occurs primarily in relatively undisturbed lowland native grasslands dominated by tussock-forming grasses, such as kangaroo grass (Themeda triandra) ^{(6) (7) (8)}. Originally thought to be confined exclusively to this habitat, the striped legless lizard has now been recorded in some areas which are degraded ⁽⁸⁾, or dominated by non-native species ^{(2) (4)}.

Striped legless lizard status

Classified as Vulnerable (VU) on the IUCN Red List ⁽¹⁾.

Striped legless lizard threats

The primary threat to the striped legless lizard is the loss or modification of its grassland habitat ⁽⁵⁾. Lowland native grasslands are the most threatened ecosystem in Australia, with a staggering 99 percent lost to urban and industrial development and agriculture ^{(2) (8) (14)}. As a result, the species’ range has decreased dramatically ⁽⁸⁾, with the remaining populations thought to be small and isolated as a result of habitat fragmentation ⁽²⁾. By 1995, less than 1,000 individuals were recorded across 90 sites, although researchers are hopeful that undetected populations exist ⁽³⁾.

Altered fire regimes may also pose a threat, potentially increasing predation risk, due to loss of cover, or causing direct death; however, the extent of this risk is unknown ⁽²⁾. Other possible threats include rock removal, weed invasion, predation from introduced animals, such as cats and foxes ^{(2) (9)}, persecution due to their resemblance to snakes, and collection for pets ⁽⁶⁾.

Striped legless lizard conservation

The striped legless lizard is listed as Vulnerable in Australia under Schedule 1 of the Environment Protection and Biodiversity Conservation Act (1999) ⁽⁸⁾, meaning that permission must be obtained from the government for any activity which may impact on the species ⁽²⁾. The striped legless lizard is also listed as Vulnerable under regional legislation, including the Flora and Fauna Guarantee Act (1988) in Victoria, the Threatened Species Conservation Act (1995) in New South Wales, and the Nature Conservation Act (1980) in the Australian Capital Territory ⁽⁴⁾, and it is considered Endangered in South Australia ⁽¹²⁾.

A National Species Action Plan was devised in 1999, the main aim being the maintenance of long-term, viable, wild populations. Specific conservation objectives include increasing understanding of the species, establishing a series of reserves and managed areas, increasing community awareness, and using captive populations to support research and education ⁽⁴⁾. Regional Action Plans are also in place in Victoria ⁽⁶⁾, the Australian Capital Territory ⁽⁷⁾ and New South Wales ⁽⁹⁾. In 1998, Melbourne Zoo successfully bred the striped legless lizard in captivity for the first time, and captive-bred individuals have now been released into the Organ Pipes National Park ⁽⁶⁾.

Large-scale conservation of the striped legless lizard requires conservation of its lowland native grassland habitat, and thus this species’ National Action Plan is linked to the Action Plan for temperate grassland ⁽⁷⁾. Conservation of grassland habitat will also benefit other threatened species such as the bush stone-curlew (Burhinus grallarius) and the tessellated gecko (Diplodactylus tessellates) ⁽¹⁶⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

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This species information was authored as part of the ARKive and Universities Scheme.

Glossary

Diurnal

Active during the day.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Invertebrates

Animals with no backbone.

References

1. IUCN Red List (April, 2010)
   http://www.iucnredlist.org
2. Department of the Environment, Water, Heritage and the Arts (2010) Delma impar.In: Species Profile and Threats Database. Department of the Environment, Water, Heritage and the Arts, Canberra. Available from:
   http://www.environment.gov.au/sprat.
3. Dorrough, J. and Ash, J.E. (1999) Using past and present habitat to predict the current distribution and abundance of a rare cryptic lizard, Delma impar (Pygopodidae). Australian Journal of Ecology, 24(6): 614-624.
4. Smith, W.J.S. and Robertson, P. (1999) National Recovery Plan for the Striped Legless Lizard (Delma impar) 1999-2003. New South Wales National Parks and Wildlife Service, Canberra, Australia.
5. Banks, C.B. (1992) The striped legless lizard working group: an interagency initiative to save Delma impar: an endangered reptile. International Zoo Yearbook, 31(1): 45-49.
6. Webster, A., Fallu, R. and Preece, K. (1992) Flora & Fauna Guarantee Action Statement 17: Striped Legless Lizard. The State of Victoria, Department of Sustainability and Environment.
7. ACT Government (1997) Striped Legless Lizard (Delma impar): A Vulnerable Species. Action Plan No. 2. Environment ACT, Canberra.
8. Organ, A. (2007) Advice on the Striped Legless Lizard Delma impar and Pink-tailed Worm Lizard Aprasia parapulchella, as part of the proposed Hume Highway Duplication, New South Wales. Roads and Traffic Authority, Victoria.
9. Department of Environment and Climate Change and Water (2005) Striped Legless Lizard Profile. New South Wales Government. Available at:
   http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/profile.aspx?id=10211
10. ACT Government (2004) Woodlands for Wildlife: ACT Lowland Woodland Conservation Strategy. Action Plan No. 27. Environment ACT, Canberra.
11. Institute for Applied Ecology (April, 2010)
    http://aerg.canberra.edu.au/pub/aerg/herps/fndelma.htm
12. Department for Environment and Heritage (2007) Striped Legless Lizard Delma impar: Fact Sheet. Biodiversity Conservation Programs, Government of South Australia. Available at:
    http://www.environment.sa.gov.au/biodiversity/southeast-bcp/pdfs/striped-legless-lizard.pdf
13. Kutt, A.S., Coulson, G. and Wainer, J. (1998) Diet of the striped legless lizard Delma impar (Squamata: pygopodidae) in a Western (Balsalt) Plains Grassland, Victoria. Australian Zoologist, 30(4): 412-418.
14. Taylor, S.C. (1998) South-eastern Australian temperate lowland native grasslands: protection levels and conservation. PARKS, 8(3): 21-26.
15. Yen, A.L. (1999) Grassland invertebrates of the western Victorian basalt plains: plant crunchers or forgotten lunches? In: Jones, R.N. (Ed.) The Great Plains Crash: Proceedings of a Conference on the Grasslands and Grassy Woodlands of Victoria. Victorian Institute of Technology, October 1992.
16. Michael, D.R., Lunt, I.D. and Robinson, W.A. (2004) Enhancing fauna habitat in grazed native grasslands and woodlands: use of artificially placed log refuges by fauna. Wildlife Research, 31: 65-71.