Emerald tree monitor

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Emerald tree monitor [1]
Varanus prasinus.jpg
CITES Appendix II (CITES)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Varanidae
Genus: Varanus
Subgenus: Hapturosaurus
Species:
V. prasinus
Binomial name
Varanus prasinus
Schlegel, 1839
Varanus prasinus range.png
Distribution of the emerald tree monitor, shown in red.
Emerald tree monitor Lizards Alive - Fernbank Museum - Atlanta - Flickr - hyku (18).jpg
Emerald tree monitor

The emerald tree monitor (Varanus prasinus) or green tree monitor, is a small to medium-sized arboreal monitor lizard. It is known for its unusual coloration, which consists of shades from green to turquoise, topped with dark, transverse dorsal banding. This coloration helps camouflage it in its arboreal habitat. [3] Its color also makes the emerald tree monitor highly prized in both the pet trade and zoos alike. [4]

Contents

Names

It is known as wbl km in the Kalam language of Papua New Guinea. [5]

Taxonomy

Varanus prasinus was first described as Monitor viridis by John Edward Gray in 1831; however, Gray's original holotype (RMNH 4812 in the National Natural History Museum in Leiden) was lost and the species was redescribed by Schlegel eight years later as V. prasinus using the found specimen. [6] The generic name Varanus is derived from the Arabic word waral (ورل), which translates to English as "monitor". [7] Its specific name, prasinus, is Latin for the color green.

Varanus prasinus is a member of the subgenus Hapturosaurus and is closely related to several other arboreal species. However, this species may be paraphyletic, as V. bogerti was found to clade inside it. This indicates that V. prasinus may actually be composed of multiple species, although the paraphyly may instead be a result of introgression or incomplete lineage sorting. [8]

In addition to V. prasinus, this subgenus, whose members are all allopatric, includes V. beccarii (Aru Islands), V. boehmei (Waigeo Island), V. bogerti (D'Entrecasteaux Archipelago), V. keithhornei (Cape York Peninsula), V. kordensis (Biak Island), V. macraei (Batanta Island), V. reisingeri (Misool Island) and V. telenesetes (Rossel Island). [9] [10]

Evolutionary history

The family Varanidae probably originated in Asia about 65 million years ago, [11] although some estimates are as early as the late Mesozoic (112 million years ago). [12] Monitor lizards probably migrated to Australia and the Indonesian archipelago between 39 and 26 million years ago. [13] All members of the V. prasinus species group (sometimes referred to as subgenus Euprepiosaurus) are found east of Lydekker’s line in the Indo-Australian Archipelago. [14] This group probably originated in the Moluccas, although dating their origins is complicated by the paucity of the fossil record. [15] The absence of large placental predatory mammals east of Wallace's line may be partially responsible for the radiation of the V. prasinus group in the Australo-Papuan region. [16]

Distribution

Emerald tree monitors and their close relatives can be found on the island of New Guinea (split between Indonesia and Papua New Guinea) as well as several adjacent islands, [17] and the northern Torres Strait Islands. [18] The green tree monitor is reported to thrive in lowland environments, including tropical evergreen forests, palm swamps and cocoa plantations. [18]

Description

Emerald tree monitors at the Bristol Zoo Green.tree.monitor.lizard.arp.jpg
Emerald tree monitors at the Bristol Zoo

The emerald tree monitor is about 75–100 cm (30–39 in) long with a slender body that helps it support itself on narrow branches. It uses its prehensile tail and long claws to grip branches. [3] [19] [20] Unlike other varanids, this monitor defends its tail rather than lashing with it for defence when threatened. [21] The soles of the feet of the emerald tree monitor have enlarged scales which aid the lizard when climbing. [20]

Ecology

When threatened, the emerald tree monitor will flee through vegetation or bite if cornered.

It is one of the few social monitors, living in small groups made up of a dominant male, several females, and a few other males and juveniles. [3]

Diet

Emerald tree monitor skull Varanus prasinus skull (cropped).png
Emerald tree monitor skull

The emerald tree monitor's diet consists of large tree-dwelling arthropods, such as katydids, grasshoppers, other orthopterans, stick insects, cockroaches, beetles, centipedes, spiders and crabs, as well as birds and small mammals (such as the Moncton's mosaic-tailed rat). [22] [23] Before swallowing stick insects, the lizards tear off the legs. [17] Captive specimens tear off the limbs of rodents prior to eating them; as a result, they are capable of swallowing mammals of a considerable size: A 135-g lizard was documented as eating a 40-g rodent, almost one-third its size. Paleontologist and Temple University professor Michael Balsai has observed V. prasinus eating fruit (bananas) in captivity as has herpetologist and author Robert G. Sprackland. [21] [24]

Despite a lack of aquatic adaptations, the Bronx Zoo has recorded a captive emerald tree monitor swimming and foraging for food under shallow water. [25]

Reproduction

Clutches consist of up to five eggs, each weighing 10.5–11.5 g (0.37–0.41 oz) and measuring about 2 by 4.5 cm (0.79 by 1.77 in). As many as three clutches are laid throughout the year; clutches have been laid by captives in January, March, April, November, and December. The female emerald tree monitor lays her eggs in arboreal termite nests. [20] The eggs hatch between 160 and 190 days later, typically from June to November, after which the young eat the termites and the termite's eggs within minutes of hatching. [20] Sexual maturity is reached in about one year. [7]

Related Research Articles

<span class="mw-page-title-main">Varanidae</span> Family of lizards

The Varanidae are a family of lizards in the superfamily Varanoidea and order Anguimorpha. The family, a group of carnivorous and frugivorous lizards, includes the living genus Varanus and a number of extinct genera more closely related to Varanus than to the earless monitor lizard (Lanthanotus). Varanus includes the Komodo dragon, crocodile monitor, savannah monitor, the goannas of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the earless monitor lizard and Chinese crocodile lizard. The oldest members of the family are known from the Late Cretaceous of Mongolia.

<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">Black tree monitor</span> Species of reptile

The black tree monitor or Beccari's monitor is a species of lizard in the family Varanidae. The species is a relatively small member of the family, growing to about 90–120 cm (35–47 in) in total length. V. beccarii is endemic to the Aru Islands off New Guinea, living in an arboreal habitat. The skin color of adults is completely black, to which one common name refers.

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

The peacock monitor, also known commonly as Auffenberg's monitor, is a species of small monitor lizard in the family Varanidae. The species, which belongs to the subgenus Odatria, is endemic to Rote Island, Indonesia.

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

The golden-spotted tree monitor, also known commonly as the golden speckled tree monitor, is a species of monitor lizard in the family Varanidae. The species is endemic to Waigeo Island in Indonesia.

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

The peach-throated monitor, also known as the Sepik monitor, is a species of monitor lizard native to New Guinea.

The Pilbara monitor, also known commonly as Bush's monitor, Bush's pygmy monitor, and the Pilbara mulga goanna, is a species of monitor lizard in the family Varanidae. The species is endemic to Australia.

<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">Ceram mangrove monitor</span> Species of lizard

The Ceram mangrove monitor is a species of monitor lizards found in Indonesia. Specifically, it is found on some of the central Moluccan Islands including: Ambon, Seram, Obi, Buru, and Banda. On Ambon and probably on New Guinea V. cerambonensis occurs sympatrically with Varanus indicus. It is in the indicus species group of the subgenus Euprepiosaurus.

<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.

Varanus keithhornei, commonly known as the canopy goanna, Keith Horne's monitor, blue-nosed tree monitor, or Nesbit River monitor, is a species of monitor lizards native to northeast Australia. It is a member of the Varanus prasinus species group.

Finsch's monitor is a species of monitor lizard in the family Varanidae. The species is native to New Guinea and Australia.

The Rennell Island monitor is a species of monitor lizards found in the Solomon Islands archipelago. It is also known as the Hakoi Monitor. It belongs to the subgenus Euprepiosaurus along with the canopy goanna, the peach-throated monitor, Kalabeck's monitor, and others.

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

Varanus kordensis, the Biak tree monitor, is a member of the Varanidae family found on Biak Island in Indonesia. It is also known as the Kordo tree monitor. Long considered a subspecies of the emerald tree monitor, most authorities now treat it as a separate species.

<i>Varanus macraei</i> Species of monitor lizard

Varanus macraei, the blue-spotted tree monitor or blue tree monitor, is a species of monitor lizard found on the island of Batanta in Indonesia. It is named after herpetologist Duncan R. MacRae, founder of the reptile park Rimba on Bali.

<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 reisingeri</i> Species of lizard

Varanus reisingeri, known commonly as Reisinger's tree monitor and the Yellow tree monitor, is a species of monitor lizard in the family Varanidae. The species is endemic to Indonesia. It was at one point at least considered an allopatric insular subspecies of the green tree monitor, due to physical and genetic similarities.

Bogert's monitor is a species of tree-dwelling monitor lizard. The species is native to Papua New Guinea.

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

Hapturosaurus, sometimes known as the tree monitors, is a subgenus of lizards, consisting of slender-bodied arboreal monitor lizards mostly found in the tropical rainforests of Indonesia and Papua New Guinea.

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

Varanus tsukamotoi, the Mariana monitor or Saipan monitor, is a species of lizard of the Varanidae family. It is endemic to the Northern Mariana Islands and Guam, and has been introduced to Japtan in the Marshall Islands.

References

  1. ↑ "Varanus prasinus". Integrated Taxonomic Information System . Retrieved 28 August 2008.
  2. ↑ Shea, G., Allison, A., Parker, F. & Tallowin, O. 2018. Varanus prasinus. The IUCN Red List of Threatened Species 2018: e.T42485751A101752115. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T42485751A101752115.en.
  3. 1 2 3 Wilson, Don W.; Burnie, David (2001). Animal. London: DK. p. 422. ISBN   978-0-7894-7764-4.
  4. ↑ Bartlett, Patricia Pope; Bartlett, Richard D. (1996). Monitors, Tegus, and Related Lizards: Everything About Selection, Care, Nutrition, Diseases, Breeding, and Behavior. Woodbury, N.Y: Barron's Educational Series. p. 63. ISBN   978-0-8120-9696-5.
  5. ↑ Bulmer, RNH (1975). "Kalam Classification of Reptiles And Fishes". Journal of the Polynesian Society. 84 (3): 267–308. Archived from the original on 1 December 2020. Retrieved 22 September 2019.
  6. ↑ Bennett, D. (1995). A Little Book of Monitor Lizards. Aberdeen, UK: Viper Press.
  7. 1 2 King, Ruth Allen; Pianka, Eric R.; King, Dennis (2004). Varanoid Lizards of the World. Bloomington: Indiana University Press. pp. 225–229. ISBN   978-0-253-34366-6.
  8. ↑ Weijola, Valter; Vahtera, Varpu; Lindqvist, Christer; Kraus, Fred (14 March 2019). "A molecular phylogeny for the Pacific monitor lizards (Varanus subgenus Euprepiosaurus) reveals a recent and rapid radiation with high levels of cryptic diversity". Zoological Journal of the Linnean Society. 186 (4): 1053–1066. doi:10.1093/zoolinnean/zlz002. ISSN   0024-4082.
  9. ↑ Jacobs, H. J. (2003). A further new emerald tree monitor lizard of the Varanus prasinus species group from Waigeo, West Irian (Squamata: Sauria: Varanidae). Salamandra 39(2): 65-74
  10. ↑ Ziegler, T.; A. Schmitz; A. Koch & W. Böhme (2007). "A review of the subgenus Hapturosaurus of Varanus (Squamata: Varanidae): morphological and molecular phylogeny, distribution and zoogeography, with an identification key for the members of the V. indicus and the V. prasinus species groups" (PDF). Zootaxa. 1472: 1–28. doi:10.11646/zootaxa.1472.1.1.
  11. ↑ Zheng, Yuchi; Wiens, John J. (2016). "Combining phylogenomic and supermatrix approaches, and a time-calibrated phylogeny for squamate reptiles (lizards and snakes) based on 52 genes and 4162 species". Molecular Phylogenetics and Evolution. 94 (Pt B): 537–547. doi:10.1016/j.ympev.2015.10.009. PMID   26475614.
  12. ↑ Schulte, JA; Melville, J; Larson, A (2003). "Molecular phylogenetic evidence for ancient divergence of lizard taxa on either side of Wallace's Line". Proceedings of the Royal Society B: Biological Sciences. 270 (1515): 597–603. doi:10.1098/rspb.2002.2272. PMC   1691285 . PMID   12769459.
  13. ↑ Vidal, N; Marin, J; Sassi, J; Battistuzzi, FU; Donnellan, S; Fitch, AJ; Fry, BG; Vonk, FJ; Rodriguez de la Vega, RC; Couloux, A; Hedges, SB (2012). "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. PMC   3441001 . PMID   22809723.
  14. ↑ Ziegler, Thomas; Schmitz, Andreas; Koch, André; Böhme, Wolfgang (2007). "A review of the subgenus Euprepiosaurus of Varanus (Squamata: Varanidae): morphological and molecular phylogeny, distribution and zoogeography, with an identification key for the members of the V. indicus and the V. prasinus species groups". Zootaxa. 1472: 1–28. doi:10.11646/zootaxa.1472.1.1.
  15. ↑ Molnar, Ralph E. (2004). "The long and honorable history of monitors and their kin". In Pianka, Eric R.; King, Dennis R.; King, Ruth Allen (eds.). Varanoid Lizards of the World. Bloomington, Indiana: Indiana University Press. pp. 10–67. ISBN   0253343666.
  16. ↑ Sweet, Samuel S.; Pianka, Eric R. (2007). "Monitors, mammals, and Wallace's Line" (PDF). Mertensiella. 16: 79–99.
  17. 1 2 Pianka, Eric R. (2006). Lizards: Windows to the Evolution of Diversity. Berkeley: University of California Press. p.  247. ISBN   978-0-520-24847-2.
  18. 1 2 Cogger, H. G. (2000). Reptiles & Amphibians of Australia (6th ed.). Sydney: Reed New Holland. p. 371. ISBN   978-1-876334-33-8. OCLC   807420701.
  19. ↑ Cogger, Harold; Zweifel, Richard (1992). Reptiles & Amphibians. Sydney: Weldon Owen. ISBN   978-0-8317-2786-4.
  20. 1 2 3 4 Greene, Harry W. (1986). Diet and Arboreality in the Emerald Monitor, Varanus Prasinus, With Comments on the Study of Adaptation. Field Museum of Natural History. OCLC   14915452.
  21. 1 2 Robert George Sprackland (1992). Giant lizards. Neptune, NJ: T.F.H. Publications. pp. 137–142. ISBN   978-0-86622-634-9.
  22. ↑ "Varanus prasinus (Emerald Monitor)". Animal Diversity Web .
  23. ↑ "Varanus Prasinus".
  24. ↑ Balsai, Michael (1997). The General Care and Maintenance of Popular Monitors and Tegus. BowTie. p.  6. ISBN   978-1-882770-39-7.
  25. ↑ Shuter, Avishai (2014). "A Novel Underwater Foraging Behavior Observed in Varanus prasinus at the Wildlife Conservation Society's Bronx Zoo". BIAWAK. 8 (2): 61–63.
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