fbpx
Wikipedia

Spiny-tailed monitor

January 01, 1970

The spiny-tailed monitor[2] (Varanus acanthurus), also known as the Australian spiny-tailed monitor, the ridge-tailed monitor[3] the Ackie dwarf monitor, and colloquially simply ackie monitor,[4] is an Australian species of lizard belonging to the genus of monitor lizards (Varanus).

Spiny-tailed monitor
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Varanidae
Genus: Varanus
Subgenus: Odatria
Species:
V. acanthurus
Binomial name
Varanus acanthurus
Boulenger, 1885
Subspecies
  • V. a. acanthurus
  • V. a. brachyurus
  • V. a. insulanicus
Distribution of the spiny-tailed monitor
"Red ackie" (V. a. acanthurus)

Description edit

The spiny-tailed monitor, a somewhat small monitor lizard, can attain a total length of up to 70 cm (27 in), although there are unconfirmed reports of wild individuals growing up to 34 inches.[5] The tail is about 1.3-2.3 times as long as the head and body combined. The upper side is a rich, dark brown and painted with bright-yellowish to cream spots, which often enclose a few dark scales. Its tail is round in section and features very spinose scales. There are 70-115 scales around the middle of the body.[3] The spiny-tailed monitor is distinguished from the similar-looking species V. baritji and V. primordius by the presence of pale longitudinal stripes on the neck.[2]

Distribution and habitat edit

This arid-adapted[6] lizard is found in northern Western Australia, in the Northern Territory and in the western and north-western parts of Queensland.[6] The spiny-tailed monitor inhabits is associated with arid rocky ranges and outcrops.[2][3] V. a. acanthurus is native to northern Australia, from Broome on the west coast, through the Kimberley and the Top End, to the Gulf of Carpentaria. V. a. brachyurus can be found in the center, western, and eastern parts of the ackie's total range, as far west as Carnarvon and as far east as Mt. Isa. V. a. insulanicus' range is limited to Groote Eylandt and the Wessel Islands.[7]

Subspecies and taxonomy edit

The spiny-tailed monitor is part of an Indonesian and Australian radiation of dwarf monitor lizards, the subgenus Odatria.[8][9]

Three subspecies of V. acanthurus are recognized:

Varanus primordius was at one point considered a subspecies (V. a. primordius), but has since been elevated to full species status.

In the pet trade, two "variants" of spiny-tailed monitors are commonly available. The "red ackie" monitor is likely the subspecies V. a. acanthurus, while the "yellow ackie" is likely V. a. brachyurus. The red ackie is generally larger and less commonly available than the yellow ackie.[5][11]

The taxonomic status of the three subspecies is uncertain.[10] In 2006, the results of a study on the mtDNA of Australian monitors were published, according to which the two continental subspecies do not form natural (monophyletic) taxonomic entities. V. a. insulanicus was found to be monophyletic, but it is more closely related to V. baritji than to other V. acanthurus. Therefore, V. a. insulanicus might represent a distinct species.[9] Wilson and Swan (2010) still accept V. a. insulanicus as a valid subspecies of V. acanthurus, which is easily distinguished from other spiny-tailed monitors by its dark colouration and more banded pattern.[2]

 
Two spiny-tailed monitors at the Cincinnati Zoo
 
Head view

Ecology edit

Spiny-tailed monitors are diurnal, typically solitary ground-dwellers. This species is most often found in its shelter, mainly under rock slabs, wedged among boulders or in rock crevices, and in burrows. Only rarely do they hide in spinifex.[3] Sheltering underground gives them access to humid microclimates which helps keep them hydrated enough to survive the otherwise arid nature of their habitat. Their diet is consistent with the diet of intensive foragers, implying that they likely spend quite a bit of their time hunting.[12]

Diet edit

They prey mainly on arthropods, such as grasshoppers, beetles, cockroaches, spiders, isopods, caterpillars, cicadas, snails, stick insects, centipedes, crickets, and ticks.[12] Small lizards such as skinks, geckos, dragon lizards, or possibly smaller monitor lizards are also eaten, making up about a third of its diet, as well as marsupial joeys.[13][14][15] Approximately 70% of its water requirement comes from food.[6]

In captivity, they are sometimes fed cat and dog food as well as processed canned food. This isn't recommended as this type of food doesn't contain the correct nutrients for this species.[16] A varied diet rich with different vertebrate and invertebrate prey (such as Dubia roaches, crickets, mealworms, eggs, shrimp, and, on a monthly basis, rodents) is important to the health of captive spiny-tailed monitors, as they naturally have a wide range of prey in the wild.[12][17]

Reproduction edit

There are a number of methods of sexing ackie monitors, although the hemipenal transillumination technique[18] is generally considered to be the easiest and most accurate. Sex can also be guessed using visual markers, but it is typically not nearly as accurate. Male ackie monitors are generally larger, have blockier heads, and have grippy scales on the underside of their tail. Females are generally smaller with narrower, pointier heads, and smooth scales under their tail.[19]

In captivity, a clutch consists of up to 18 eggs. The young hatch after three to five months of incubation, and measure 15 cm (6 in). The knowledge on reproduction in the wild is sparse. Males most likely mature at 30 cm (12 in) snout-vent length, females mature at 25–36 cm (10–14 in) snout-vent length. Ovulation occurs in August and November. The eggs are deposited in self-dug tunnels.[6] In the wild, females have been shown to share massive burrows, nesting communally.[20]

References edit

 
Wikimedia Commons has media related to Varanus acanthurus.
  1. ^ Shea, G.; Cogger, H. (2018). "Varanus acanthurus". IUCN Red List of Threatened Species. 2018: e.T83777229A101752285. doi:10.2305/IUCN.UK.2018-1.RLTS.T83777229A101752285.en. Retrieved 19 November 2021.
  2. ^ a b c d e Wilson S, Swan G. 2010. A complete guide to reptiles of Australia. New Holland Publishers, Sydney, Auckland, London, Cape Town. ISBN 978-1-877069-76-5. P 392.
  3. ^ a b c d e Cogger H. 2000. Reptiles & Amphibians of Australia. Ralph Curtis Publishing, Sanibel Island, Florida. ISBN 0-88359-048-4. Pp 359-361.
  4. ^ . Archived from the original on 2012-09-05. Retrieved 2012-08-28.
  5. ^ a b "Spiny-Tailed Monitor Lizard Care Tips". Reptiles Magazine. 2011-12-01. Retrieved 2020-08-29.
  6. ^ a b c d Dryden G. 2004. Varanus acanthurus. In: Varanoid Lizards of the World (Hrsg. Pianka ER, King DR), pp 298-307. Indiana University Press, Bloomington & Indianapolis. ISBN 0-253-34366-6.
  7. ^ Monitor lizards natural history, captive care, breeding. Bernd Eidenmüller, Grant Husband (Rev., enl. and updated ed.). Frankfurt, M. 2007. ISBN 978-3-89973-471-3. OCLC 185009165.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  8. ^ Böhme W. 2003. Checklist of the living monitor lizards of the world (family Varanidae). Zoologische Verhandelingen 341, pp 3–43.
  9. ^ a b Fitch AJ, Goodman AE, Donnellan SC. 2006. A molecular phylogeny of the Australian monitor lizards (Squamata:Varanidae) inferred from mitochondrial DNA sequences. Australian Journal of Zoology 54, p 253-269.
  10. ^ a b Auliya, Marc; Koch, André (2020). Visual Identification Guide for the Monitor Lizard Species of the World (Genus Varanus). Bundesamt für Naturschutz. doi:10.19217/skr552. ISBN 9783896242907.
  11. ^ Kuhn, Peter; Julander, Justin (1999). "Husbandry and Captive Breeding of the Red Acanthurus Monitor Varanus acanthurus: A Giant Dwarf". Vivarium. 10.
  12. ^ a b c King, Dennis (2008). "The Diet and Foraging Strategy of Varanus acanthurus" (PDF). Biawak. 2 (1): 11–17.
  13. ^ Losos, Jonathan B.; Greene, Harry W. (1988-12-01). "Ecological and evolutionary implications of diet in monitor lizards". Biological Journal of the Linnean Society. 35 (4): 379–407. doi:10.1111/j.1095-8312.1988.tb00477.x. ISSN 0024-4066.
  14. ^ "Ackie's Dwarf Monitor". 14 January 2021.
  15. ^ "Varanus Acantiiurus".
  16. ^ "Ackie Monitor". Reptile Range. Retrieved 9 August 2022.
  17. ^ "Ackies Monitor Care: Size, Enclosure, Lifespan, Diet". 21 June 2020.
  18. ^ Brown, Danny (2009). "Hemipenal Transillumination as a Sexing Technique in Varanids" (PDF). Biawak. 3 (1): 26–29.
  19. ^ "Ackie Monitor". Reptile Range. Retrieved 8 January 2024.
  20. ^ Doody, J. & Clulow, Simon & McHenry, Colin & Brown, Michael & Vas, Gary & Canning, Gordon. (2017). Varanus acanthurus (Spiny-tailed Monitor Lizard). Communal nesting and commensalism. Herpetological Review. 48. 203.

January 01, 1970
spiny, tailed, monitor, spiny, tailed, monitor, varanus, acanthurus, also, known, australian, spiny, tailed, monitor, ridge, tailed, monitor, ackie, dwarf, monitor, colloquially, simply, ackie, monitor, australian, species, lizard, belonging, genus, monitor, l. The spiny tailed monitor 2 Varanus acanthurus also known as the Australian spiny tailed monitor the ridge tailed monitor 3 the Ackie dwarf monitor and colloquially simply ackie monitor 4 is an Australian species of lizard belonging to the genus of monitor lizards Varanus Spiny tailed monitor Conservation status Least Concern IUCN 3 1 1 Scientific classification Domain Eukaryota Kingdom Animalia Phylum Chordata Class Reptilia Order Squamata Family Varanidae Genus Varanus Subgenus Odatria Species V acanthurus Binomial name Varanus acanthurusBoulenger 1885 Subspecies V a acanthurus V a brachyurus V a insulanicus Distribution of the spiny tailed monitor Red ackie V a acanthurus Contents 1 Description 2 Distribution and habitat 3 Subspecies and taxonomy 4 Ecology 4 1 Diet 5 Reproduction 6 ReferencesDescription editThe spiny tailed monitor a somewhat small monitor lizard can attain a total length of up to 70 cm 27 in although there are unconfirmed reports of wild individuals growing up to 34 inches 5 The tail is about 1 3 2 3 times as long as the head and body combined The upper side is a rich dark brown and painted with bright yellowish to cream spots which often enclose a few dark scales Its tail is round in section and features very spinose scales There are 70 115 scales around the middle of the body 3 The spiny tailed monitor is distinguished from the similar looking species V baritji and V primordius by the presence of pale longitudinal stripes on the neck 2 Distribution and habitat editThis arid adapted 6 lizard is found in northern Western Australia in the Northern Territory and in the western and north western parts of Queensland 6 The spiny tailed monitor inhabits is associated with arid rocky ranges and outcrops 2 3 V a acanthurus is native to northern Australia from Broome on the west coast through the Kimberley and the Top End to the Gulf of Carpentaria V a brachyurus can be found in the center western and eastern parts of the ackie s total range as far west as Carnarvon and as far east as Mt Isa V a insulanicus range is limited to Groote Eylandt and the Wessel Islands 7 Subspecies and taxonomy editThe spiny tailed monitor is part of an Indonesian and Australian radiation of dwarf monitor lizards the subgenus Odatria 8 9 Three subspecies of V acanthurus are recognized V a acanthurus of northwestern and northern Australia V a brachyurus of western and central Australia Queensland 10 V a insulanicus of Groote Eylandt and the islands of the Wessel group 2 3 Varanus primordius was at one point considered a subspecies V a primordius but has since been elevated to full species status In the pet trade two variants of spiny tailed monitors are commonly available The red ackie monitor is likely the subspecies V a acanthurus while the yellow ackie is likely V a brachyurus The red ackie is generally larger and less commonly available than the yellow ackie 5 11 The taxonomic status of the three subspecies is uncertain 10 In 2006 the results of a study on the mtDNA of Australian monitors were published according to which the two continental subspecies do not form natural monophyletic taxonomic entities V a insulanicus was found to be monophyletic but it is more closely related to V baritji than to other V acanthurus Therefore V a insulanicus might represent a distinct species 9 Wilson and Swan 2010 still accept V a insulanicus as a valid subspecies of V acanthurus which is easily distinguished from other spiny tailed monitors by its dark colouration and more banded pattern 2 nbsp Two spiny tailed monitors at the Cincinnati Zoo nbsp Head viewEcology editSpiny tailed monitors are diurnal typically solitary ground dwellers This species is most often found in its shelter mainly under rock slabs wedged among boulders or in rock crevices and in burrows Only rarely do they hide in spinifex 3 Sheltering underground gives them access to humid microclimates which helps keep them hydrated enough to survive the otherwise arid nature of their habitat Their diet is consistent with the diet of intensive foragers implying that they likely spend quite a bit of their time hunting 12 Diet edit They prey mainly on arthropods such as grasshoppers beetles cockroaches spiders isopods caterpillars cicadas snails stick insects centipedes crickets and ticks 12 Small lizards such as skinks geckos dragon lizards or possibly smaller monitor lizards are also eaten making up about a third of its diet as well as marsupial joeys 13 14 15 Approximately 70 of its water requirement comes from food 6 In captivity they are sometimes fed cat and dog food as well as processed canned food This isn t recommended as this type of food doesn t contain the correct nutrients for this species 16 A varied diet rich with different vertebrate and invertebrate prey such as Dubia roaches crickets mealworms eggs shrimp and on a monthly basis rodents is important to the health of captive spiny tailed monitors as they naturally have a wide range of prey in the wild 12 17 Reproduction editThere are a number of methods of sexing ackie monitors although the hemipenal transillumination technique 18 is generally considered to be the easiest and most accurate Sex can also be guessed using visual markers but it is typically not nearly as accurate Male ackie monitors are generally larger have blockier heads and have grippy scales on the underside of their tail Females are generally smaller with narrower pointier heads and smooth scales under their tail 19 In captivity a clutch consists of up to 18 eggs The young hatch after three to five months of incubation and measure 15 cm 6 in The knowledge on reproduction in the wild is sparse Males most likely mature at 30 cm 12 in snout vent length females mature at 25 36 cm 10 14 in snout vent length Ovulation occurs in August and November The eggs are deposited in self dug tunnels 6 In the wild females have been shown to share massive burrows nesting communally 20 References edit nbsp Wikimedia Commons has media related to Varanus acanthurus Shea G Cogger H 2018 Varanus acanthurus IUCN Red List of Threatened Species 2018 e T83777229A101752285 doi 10 2305 IUCN UK 2018 1 RLTS T83777229A101752285 en Retrieved 19 November 2021 a b c d e Wilson S Swan G 2010 A complete guide to reptiles of Australia New Holland Publishers Sydney Auckland London Cape Town ISBN 978 1 877069 76 5 P 392 a b c d e Cogger H 2000 Reptiles amp Amphibians of Australia Ralph Curtis Publishing Sanibel Island Florida ISBN 0 88359 048 4 Pp 359 361 Cincinnati Zoo amp Botanical Garden Archived from the original on 2012 09 05 Retrieved 2012 08 28 a b Spiny Tailed Monitor Lizard Care Tips Reptiles Magazine 2011 12 01 Retrieved 2020 08 29 a b c d Dryden G 2004 Varanus acanthurus In Varanoid Lizards of the World Hrsg Pianka ER King DR pp 298 307 Indiana University Press Bloomington amp Indianapolis ISBN 0 253 34366 6 Monitor lizards natural history captive care breeding Bernd Eidenmuller Grant Husband Rev enl and updated ed Frankfurt M 2007 ISBN 978 3 89973 471 3 OCLC 185009165 a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link CS1 maint others link Bohme W 2003 Checklist of the living monitor lizards of the world family Varanidae Zoologische Verhandelingen 341 pp 3 43 a b Fitch AJ Goodman AE Donnellan SC 2006 A molecular phylogeny of the Australian monitor lizards Squamata Varanidae inferred from mitochondrial DNA sequences Australian Journal of Zoology 54 p 253 269 a b Auliya Marc Koch Andre 2020 Visual Identification Guide for the Monitor Lizard Species of the World Genus Varanus Bundesamt fur Naturschutz doi 10 19217 skr552 ISBN 9783896242907 Kuhn Peter Julander Justin 1999 Husbandry and Captive Breeding of the Red Acanthurus Monitor Varanus acanthurus A Giant Dwarf Vivarium 10 a b c King Dennis 2008 The Diet and Foraging Strategy of Varanus acanthurus PDF Biawak 2 1 11 17 Losos Jonathan B Greene Harry W 1988 12 01 Ecological and evolutionary implications of diet in monitor lizards Biological Journal of the Linnean Society 35 4 379 407 doi 10 1111 j 1095 8312 1988 tb00477 x ISSN 0024 4066 Ackie s Dwarf Monitor 14 January 2021 Varanus Acantiiurus Ackie Monitor Reptile Range Retrieved 9 August 2022 Ackies Monitor Care Size Enclosure Lifespan Diet 21 June 2020 Brown Danny 2009 Hemipenal Transillumination as a Sexing Technique in Varanids PDF Biawak 3 1 26 29 Ackie Monitor Reptile Range Retrieved 8 January 2024 Doody J amp Clulow Simon amp McHenry Colin amp Brown Michael amp Vas Gary amp Canning Gordon 2017 Varanus acanthurus Spiny tailed Monitor Lizard Communal nesting and commensalism Herpetological Review 48 203 Retrieved from https en wikipedia org w index php title Spiny tailed monitor amp oldid 1194312720, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.