Varanus (Odatria)

Last updated

Varanus (Odatria)
Ackies Dwarf Monitor.jpg
Spiny-tailed monitor at the Cincinnati Zoo
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Varanidae
Genus: Varanus
Subgenus: Odatria
Gray, 1838
Type species
Varanus tristis
Schlegel, 1839
Species

Odatria, commonly known as dwarf monitors, [1] consists of small monitor lizards found in Australia and Indonesia. Species in this subgenus include the smallest monitor species in the world, the tiny 16 gram Dampier Peninsula monitor, but also includes some more medium sized species such as the 240 gram black-palmed rock monitor. [2]

Contents

Taxonomy

Odatria was coined by John Edward Gray in 1838, albeit as a genus name.

Odatria is the most species diverse subgenus of monitor lizards, with 22 different species. The subgenus also includes two species complexes represented by the spiny-tailed monitor and the Timor monitor. Alternatively, Vidal et al. 2012 splits Odatria into two species groups represented by the spiny-tailed monitor and the black-headed monitor.

In the past, tree monitors such as the green tree monitor have sometimes been included within Odatria as well as Euprepriosaurus, but now form their own subgenus Hapturosaurus .

A 2020 phylogenomic study by Brennan et al. found that Odatria is most closely related to much larger Australian monitor lizards from the subgenus Varanus, which includes the largest living lizard, the Komodo dragon, as well as the monotypic subgenus Papusaurus of which the crocodile monitor is the only member of. Together, Odatria, Varanus, and Papusaurus form a monophyletic clade of Indo-Australopapuan monitors. [3]

The same study found the black-palmed rock monitor, the largest species within Odatria, as sister to the rest of Odatria, making it the most basal species within the subgenus. [3] Vidal et al. 2012 also recovers this species as the most basal, although within the V. tristis group. [4]

During the early-mid Oligocene, the genus Varanus dispersed in two directions. The southeastern dispersion into Indo-Australia likely occurred shortly after the collision of the Asian and Australian tectonic plates, which created a connection between Sahul and Sundaland, i.e., an Indonesian land bridge that would have facilitated the dispersal of monitor lizards into Australia. The existence of this land bridge also likely allowed the Indo-Australopapuan clade including many Odatria species to disperse back into Indonesia. [3] True monitors (subgenus Varanus ) and Papuan monitors (subgenus Papusaurus ) form a clade that is considered the sister taxon of Odatria. [5]

Phylogeny

Species Groups

Vidal et al. 2012 separated Odatria into two species groups; the V. acanthurus group included V. acanthurus, V. baritji, V. brevicauda, V. bushi, V. caudolineatus, V. eremius, V. gilleni, V. kingorum, V. primordius, and V. storri, while the V. tristis group included V. auffenbergi, V. glauerti, V. glebopalma, V. mitchelli, V. pilbarensis, V. scalaris, V. semiremex, V. similis, V. timorensis, and V. tristis. [4]

To maintain monophyly in light of Brennan et al. 2020, V. glebopalma would be excluded from the V. tristis group, and more species would be included as in the following:

V. acanthurus group - (V. acanthurus, V. baritji, V. brevicauda, V. bushi, V. caudolineatus, V. eremius, V. gilleni, V. kingorum, V. primordius, V. sparnus and V. storri)

V. tristis group - (V. auffenbergi, V. glauerti, V. hamersleyensis, V. mitchelli, V. pilbarensis, V. scalaris, V. semiremex, V. similis, V. timorensis, and V. tristis)

Brennan et al. 2020Vidal et al. 2012
Odatria.png Odatria (Vidal et al. 2012).png

Ecology

Behaviour

The genus is diverse in terms of behaviour, and includes terrestrial, arboreal, and semiaquatic species. Many are saxicolous, i.e., they are strongly associated with rocky habitats, while some others prefer forests. [2]

Ritualized fighting sometimes occurs between males. Unlike many larger monitors which grapple with each other while standing on their hind legs, some dwarf monitor species instead grapple each other with all 4 limbs, belly to belly, and roll around on the ground trying to force the other onto its back. Biting may also occur. [6]

Diet

Orthopteran insects and other species of lizards make up the mainstay of the diet for most species. One species, the rusty desert monitor, consumes a particularly large amount of lizard prey with lizards such as various species of Ctenotus accounting for up to 70% of their diet by weight. [7] Larger species such as black-palmed rock monitors are also known to prey on other dwarf monitors. [2]

Reproduction

Like all other monitors, all species within Odatria are oviparous. As parthenogenesis is well known in monitor lizards in some other subgenera, it is possible that dwarf monitors are also capable of parthenogenesis; there is a report of a suspected case of parthenogenesis in peacock monitors. [2]

Parasites

Physalopterid nematodes of the genus Abbreviata are major gastrointestinal parasites in many species of reptiles. Those that parasitize dwarf monitors include A. hastaspicula and A. levicauda ; the former may specialize in Australian monitors. Depending on the species, more than half of all individuals collected from the wild may be infected, but in most cases the parasites do minimal harm. Various other parasites are also known, but in comparatively much low numbers. [1] [8] In captivity, wild caught individuals may suffer more from the effects of parasites due to the stressful process of being taken from the wild and being shipped elsewhere.

Conservation and captivity

Under the EPBC Act, the export of live Australian Odatria species for commercial purposes is prohibited. Illegal trade of these species still persist, as many dwarf monitor species are in great demand in the pet trade. In Australia, monitor lizards are threatened by the invasive cane toad, as they have no natural immunity to the toad's toxins when ingested. [2]

Captive breeding for the pet trade has been successful in many such species however and lessens the pressure on wild populations. Some such as the often captive bred ridge-tailed monitor are popular pet lizards, in some cases as a "beginner monitor" to train those who are aspiring to eventually keep larger and less forgiving monitor lizard species.

Species

SpeciesTaxon authorCommon namePicture
V. glebopalma Mitchell, 1955black-palmed rock monitor Black-palmed Rock Monitor (Varanus glebopalma). Katherine, NT 2.jpg
Varanus acanthurus species group
SpeciesTaxon authorCommon namePicture
V. acanthurus Boulenger, 1885ackie monitor, Ackie's dwarf monitor, Australian spiny-tailed monitor, ridge-tailed monitor, spiny-tailed monitor Varanus acanthurus 0zz.jpg
V. baritji M. King & Horner, 1987black-spotted ridge-tailed monitor, black-spotted spiny-tailed monitor, lemon-throated monitor, northern ridge-tailed monitor, White's dwarf goanna, White's dwarf monitor, Whites monitor, yellow-throated monitor
V. brevicauda Boulenger, 1898short-tailed monitor, short-tailed pygmy monitor
V. bushi Aplin, Fitch & D.J. King, 2006Bush's monitor, Bush's pygmy monitor, Pilbara monitor, Pilbara mulga monitor, Pilbara stripe-tailed monitor
V. caudolineatus Boulenger, 1885line-tailed pygmy monitor, stripe-tailed goanna, stripe-tailed monitor Streifenschwanzwaran (Varanus caudolineatus).jpg
V. citrinus Pavón-Vázquez, Esquerré, Fitch, Maryan, Doughty, Donnellan & Keogh, 2022Gulf ridge-tailed monitor
V. eremius Lucas & Frost, 1895pygmy desert monitor, rusty desert monitor
V. gilleni Lucas & Frost, 1895Gillen's monitor, mulga monitor, pygmy mulga monitor Gillenibaumann 02.JPG
V. insulanicus Mertens, 1958Groote Eylandt monitor
V. kingorum Storr, 1980Kings' goanna, Kings' monitor, Kings' rock monitor, pygmy rock monitor Varanus kingorum Male.JPG
V. ocreatus Storr, 1980Storr's monitor, western Storr's monitor
V. primordius Mertens, 1942northern blunt-spined monitor, northern ridge-tailed monitor
V. sparnus Doughty, Keally, Fitch & Donnellan, 2014Dampier peninsula goanna, Dampier Peninsula monitor
V. storri Mertens, 1966Storr's monitor Gfp-storrs-pygmy-monitor.jpg
Varanus tristis species group
SpeciesTaxon authorCommon namePicture
V. auffenbergi Sprackland, 1999Auffenberg's monitor, peacock monitor Varanus auffenbergi by OpenCage.jpg
V. glauerti Mertens, 1957Glauert's monitor, Kakadu sand goanna, Kimberley rock monitor Kimberley-Felsenwaran (Varanus glauerti).jpg
V. hamersleyensis Maryan, Oliver, Fitch & O'Connell, 2014Hamersley Range rock monitor, Southern Pilbara rock goanna Varanus hammersleyensis.jpg
V. mitchelli Mertens, 1958Mitchell's water monitor Varanus mitchelli.jpg
V. pilbarensis Storr, 1980Pilbara rock monitor
V. scalaris Mertens, 1941banded tree monitor, spotted tree monitor
Spotted Tree Monitor (Varanus scalaris) (9334711410).jpg
V. semiremex W. Peters, 1869rusty monitor
V. similis Mertens, 1958similis monitor, spotted tree monitor
V. timorensis Gray, 1831spotted tree monitor, Timor monitor Varanus timorensis from Timor-Leste.jpg
V. tristis Schlegel, 1838black-headed monitor, black-tailed monitor, freckled monitor, mournful monitor, racehorse monitor Gillenibaumann.JPG

Related Research Articles

<span class="mw-page-title-main">Monitor lizard</span> Genus of reptiles

Monitor lizards are lizards in the genus Varanus, the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recognized.

<span class="mw-page-title-main">Goanna</span> Several species of reptiles

A goanna is any one of several species of lizard of the genus Varanus found in Australia and Southeast Asia.

<i>Varanus timorensis</i> Species of lizard

Varanus timorensis, the Timor monitor or spotted tree monitor, is a species of small monitor lizards native to the island of Timor and some adjacent islands.

<span class="mw-page-title-main">Spiny-tailed monitor</span> Species of lizard

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

<span class="mw-page-title-main">Stripe-tailed goanna</span> Species of lizard

The stripe-tailed goanna, also known as the line-tailed pygmy monitor is a semi-arboreal species of monitor lizard native to Western Australia.

The black-spotted ridge-tailed monitor, also called commonly the black-spotted spiny-tailed monitor, the lemon-throated monitor, the northern ridge-tailed monitor, Whites monitor, and the yellow-throated monitor, is a subspecies of lizard in the family Varanidae. The subspecies is native to Australia's tropical Northern Territory. It is listed as Least Concern on the IUCN Red List as it is considered common and not threatened. It was first described in 1987. It is also known as White's dwarf goanna.

<span class="mw-page-title-main">Turquoise monitor</span> Species of lizard

The turquoise monitor is a species of monitor lizards found in Indonesia. Specifically, it is found on Halmahera Island and in the Maluku Islands.

<span class="mw-page-title-main">Roughneck monitor</span> Species of lizard

The black rough-necked monitor is a species of monitor lizard found in Southeast Asian countries of Thailand, Burma, and Malaysia. It is also found in Indonesia on Sumatra and islands of the Riau Archipelago It is sometimes known simply as the roughneck monitor. In Thailand is called h̄èā cĥāng.

<span class="mw-page-title-main">Blue-tailed monitor</span> Species of lizard

The blue-tailed monitor, blue-tailed tree monitor or Kalabeck's monitor, is a monitor lizard of the Varanidae family. It belongs to the V. doreanus group of the subgenus Euprepiosaurus.

<span class="mw-page-title-main">Black-palmed rock monitor</span> Species of lizard

The black-palmed rock monitor is a member of the Varanidae family found in Australia. Also known as the twilight monitor or the long-tailed rock monitor, it is a member of the subgenus Odatria, and is found in the northern part of Australia in the Northern Territory and Western Australia, as well as Queensland. Specifically, its distribution extends from Mount Isa in the east to the Kimberleys in the west. Its habitat is areas of rock escarpment, and large populations may be found in small areas.

<span class="mw-page-title-main">Rusty desert monitor</span> Species of lizard

The rusty desert monitor is a species of small monitor lizards native to Australia. It is also known as the pygmy desert monitor. The monitor lizard belongs to the subgenus Odatria along with the pygmy mulga monitor. This monitor lizard is oviparous as with other monitor lizards.

<i>Varanus spinulosus</i> Species of lizard

Varanus spinulosus, the Solomon Island spiny monitor, Isabel monitor, or spiny-neck monitor, is a species of monitor lizard. It is endemic to the Solomon Islands archipelago and is also known from Santa Isabel Island, San Jorge Island and Bourgainville Island.

<i>Varanus storri</i> Species of lizard

Storr's monitor is a species of monitor lizard in the family Varanidae. The species is endemic to Australia.

Plasmodium auffenbergi is a parasite of the genus Plasmodium subgenus Carinamoeba.

The Yuwono monitor or tricolor monitor, also commonly known as the black-backed mangrove monitor or the black-backed monitor, is a species of monitor lizard in the blue-tailed monitor species complex. The tricolor monitor is endemic to the island of Halmahera, in the Maluku Islands, Indonesia.

The Groote Eylandt monitor is a medium-sized species of monitor lizard in the family Varanidae. The species is native to Northern Australia. It belongs to the subgenus Odatria.

<i>Varanus <span style="font-style:normal;">(</span>Varanus<span style="font-style:normal;">)</span></i> Subgenus of reptiles

Varanus, commonly known as true monitors, is one of the 11 subgenera of the genus Varanus. All of its species are found in the Australasian realm, among which are the world's largest lizards.

<i>Varanus <span style="font-style:normal;">(</span>Empagusia<span style="font-style:normal;">)</span></i> Subgenus of lizards

Empagusia is a subgenus of monitor lizards in South to Southeast Asia, which includes medium to large species.

<i>Varanus</i> (Soterosaurus) Subgenus of reptiles

Soterosaurus is a subgenus of monitor lizards commonly known as Southeast Asian water monitors. Most species are endemic to the Philippines, but black rough-necked monitors, Asian water monitors, and Togian water monitors can be found elsewhere in Southeast Asia.

References

  1. 1 2 Jones, Hugh I. (2010-07-28). "Dwarf monitor lizards (Varanidae : Varanus, Odatria s. gen.) as definitive and paratenic hosts for physalopteran nematodes". Australian Journal of Zoology. 58 (2): 69–75. doi:10.1071/ZO09122. ISSN   1446-5698.
  2. 1 2 3 4 5 Auliya, Mark (2020). Visual Identification Guide for the Monitor Lizard Species of the World (Genus Varanus). Bonn, Germany: Bundesamt für Naturschutz (BfN). pp. 80–122. ISBN   978-3-89624-290-7.
  3. 1 2 3 Brennan, Ian G.; Lemmon, Alan R.; Lemmon, Emily Moriarty; Portik, Daniel M.; Weijola, Valter; Welton, Luke; Donnellan, Stephen C.; Keogh, J. Scott (2020-02-03). "Phylogenomics of monitor lizards and the role of competition in dictating body size disparity". bioRxiv. 70 (1): 120–132. doi:10.1101/2020.02.02.931188. PMID   32521014. S2CID   211297088.
  4. 1 2 Vidal, Nicolas; Marin, Julie; Sassi, Julia; Battistuzzi, Fabia U.; Donnellan, Steve; Fitch, Alison J.; Fry, Bryan G.; Vonk, Freek J.; Rodriguez de la Vega, Ricardo C.; Couloux, Arnaud; Hedges, S. Blair (2012-10-23). "Molecular evidence for an Asian origin of monitor lizards followed by Tertiary dispersals to Africa and Australasia". Biology Letters. 8 (5): 853–855. doi:10.1098/rsbl.2012.0460. ISSN   1744-9561. PMC   3441001 . PMID   22809723.
  5. ↑ Brennan, Ian G.; Lemmon, Alan R.; Lemmon, Emily Moriarty; Portik, Daniel M.; Weijola, Valter; Welton, Luke; Donnellan, Stephen C.; Keogh, J. Scott (2020-02-03). "Phylogenomics of monitor lizards and the role of competition in dictating body size disparity". bioRxiv: 2020.02.02.931188. doi:10.1101/2020.02.02.931188. S2CID   211297088.
  6. ↑ Bennett, Daniel (1995). A little book of monitor lizards. Viper Press.
  7. ↑ Jones, Hugh I. (2010). "Dwarf monitor lizards (Varanidae:Varanus, Odatria s. gen.) as definitive and paratenic hosts for physalopteran nematodes". Australian Journal of Zoology. 58 (2): 69. doi:10.1071/ZO09122. ISSN   0004-959X.
  8. ↑ King, C.; Jones, H.I. (December 2016). "The life cycle of the reptile-inhabiting nematode Abbreviata hastaspicula (Spirurida: Physalopteridae: Physalopterinae) in Australia". International Journal for Parasitology: Parasites and Wildlife. 5 (3): 258–262. doi:10.1016/j.ijppaw.2016.08.002. PMC   5024145 . PMID   27668177.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.