Spiny tail monitor

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Spiny tail monitor
Spiny-tailed-monitor.jpg

Barbed tail monitor ( Varanus acanthurus )

Systematics
without rank: Toxicofera
without rank: Sneaky (Anguimorpha)
Family : Varanidae
Genre : Monitor lizards ( varanus )
Subgenus : Odatria
Type : Spiny tail monitor
Scientific name
Varanus acanthurus
Boulenger , 1885

The spiny-tailed monitor lizard ( Varanus acanthurus ) is an Australian scale reptile from the genus of monitor lizards ( Varanus ). In Australia it is called the Ridge-Tailed Monitor or Spiny-tailed Monitor .

features

The spiny-tail monitor reaches a total length of a maximum of 70 cm, with the tail length corresponding to 1.3-2.3 times the head-trunk length . On the upper side of the body, the species is usually dark brown and marked with light spots, which often include some darker scales and thus form eye spots. The tail has very prickly scaling and is round in cross section. Around the middle of the body there are 70-115 rows of smooth scales. The spiny-tail monitor can be distinguished from the similar species V. baritji and V. primordius because it has light vertical stripes on the neck.

distribution and habitat

Distribution area of ​​the spiny-tailed monitor

In Australia, the spiny tail monitor inhabits the northern half of Western Australia as well as the Northern Territory and the eastern to northeastern parts of Queensland. This species inhabits arid areas, especially those with rock formations.

Subspecies and systematics

The spiny-tailed monitor lizard is part of a purely Australian radiation of rather small monitor lizards, which is delimited as the sub-genus Odatria . There it is assigned to the V. acanthurus group.

For a long time the spiny-tailed monitor was split into three subspecies : V. a. acanthurus , V. a. brachyurus and V. insulanicus , which only inhabits the Groote Eylandt and the islands of the Wessel group . However, through mtDNA analyzes it became known that V. a. brachyurus and V. a. acanthurus do not form a natural group ( Monophyla ). V. a. insulanicus, on the other hand, is closer to the species V. baritji than to the spiny-tailed monitor lizards that are found on the continents. This subspecies therefore possibly represents an independent species. Wilson & Swan (2010) recognize V. a. insulanicus is still a subspecies of V. acanthurus , which can be distinguished from the nominate- shaped spiny-tailed monitor by its darker base color and more ribbon-like pattern .

Way of life

Like all monitor lizards, the spiny-tail monitor is a diurnal loner and predominantly lives on the ground. He hides at night and often during the day in crevices or under rocks, more rarely he also uses Spinifex grass as a shelter. The spiny-tailed monitor lizard is characterized by lower activity and metabolic rates than other monitor lizards and is likely to be a stalker. The most important prey of wild spiny-tail monitors are insects such as grasshoppers, beetles and cockroaches, as well as small lizards such as geckos, skinks and small agamas. The monitor lizard prey on other insects, spiders, snails or young marsupials more rarely. The spiny-tail monitor covers around 70% of its water needs from its food.

Spiny-tail monitors are attacked by ticks of the genera Amblyomma and Aponomma and parasitized by roundworms of the genus Abbreviata . While almost 3/4 of free-living spiny-tailed monitors are infested with roundworms, tick infestation is comparatively low. The predators of the monitor lizard include snakes.

Reproduction

In captivity, the spiny-tail monitor clutches contain up to 18 eggs, from which young animals 15 cm long hatch after 3–5 months. There is sparse data on reproduction in the wild. Sexual maturity is evidently reached by males from 12 cm head-trunk length and by females from 10-14 cm head-trunk length. The females ovulate in August and November (early dry season), and a clutch is apparently laid in a burrow every year.

swell

  1. ↑ a b c d e Harold G. Cogger: Reptiles & Amphibians of Australia. 6th edition. Ralph Curtis Books, Sanibel, Florida 2000, ISBN 0-88359-048-4 , pp. 359-361.
  2. ^ A b c d S. Wilson, G. Swan: A complete guide to reptiles of Australia. New Holland Publishers, Sydney / Auckland / London / Cape Town 2010, ISBN 978-1-877069-76-5 , p. 392.
  3. ↑ a b c d G. Dryden: Varanus acanthurus. In: ER Pianka, DR King (Ed.): Varanoid Lizards of the World. Indiana University Press, Bloomington & Indianapolis 2004, ISBN 0-253-34366-6 , pp. 298-307.
  4. ↑ W. Böhme: Checklist of the living monitor lizards of the world (family Varanidae). In: Zoologische Verhandelingen. 341, 2003, pp. 3-43.
  5. ↑ a b A. J. Fitch, AE Goodman, SC Donnellan: A molecular phylogeny of the Australian monitor lizards (Squamata: Varanidae) inferred from mitochondrial DNA sequences. In: Australian Journal of Zoology. 54, 2006, pp. 253-269.

Web links

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