Emerald tree monitor

Emerald Tree Monitor[1]
Conservation status
CITES Appendix II (CITES)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Order:	Squamata
Suborder:	Lacertilia
Family:	Varanidae
Genus:	Varanus
Subgenus:	Euprepiosaurus
Species:	V. prasinus
Binomial name
Varanus prasinus Schlegel, 1839
Distribution of the emerald tree monitor, shown in red.

The Emerald Tree monitor (Varanus prasinus), or the 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.^[2] It also makes the Emerald Tree monitor highly coveted by private collectors and zoos alike.^[3]

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.^[4] The generic name Varanus is derived from the Arabic word waral (ورل), which translates to English as "monitor".^[5] Its specific name, prasinus, is Latin for the color green.

V. prasinus is a member of the Euprepiosaurus subgenus. It is closely related to several other arboreal species and when combined these are often referred to as the V. prasinus species group. In addition to V. prasinus itself, this species group, 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).^[6][7]

Evolutionary development

The evolutionary development of V. prasinus started with the Varanus genus, which originated in Asia about 40 million years ago and migrated to Australia and the Indonesian archipelago around 15 million years ago.^[8]

Distribution

Emerald tree monitors and their close relatives can be found in New Guinea, as well as several adjacent islands,^[9] and the northern Torres Strait Islands.^[10] The green tree monitor is reported to thrive in lowland environments including tropical evergreen forests, palm swamps and cocoa plantations.^[10]

Description

Emerald tree monitors at the Bristol Zoo.

The emerald tree monitor is about 75–100 centimetres (30–39 in) long with a slender body that helps it support itself on narrow branches. It also has a prehensile tail and long claws that it uses to grip branches.^[2][11][12] Unlike other varanids this monitor defends its tail rather than lashing with it for defense when threatened.^[13] The soles of the feet of the emerald tree monitor have enlarged scales which aid the lizard when climbing.^[12]

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.^[2]

Diet

The emerald tree monitor's diet consists of large tree dwelling insects such as katydids, stick insects, cockroaches, beetles, centipedes, spiders, crabs, birds, and small mammals. Before swallowing stick insects, the lizards tear off the legs.^[9] Captive specimens tear off the limbs of rodents prior to eating them and as a result they are capable of swallowing mammals of a considerable size: A 135-gram (4.8 oz) lizard was documented as eating a 40-gram (1.4 oz) rodent, an animal almost one-third its size. Paleontologist and Biology Professor at Temple University, Michael Balsai has observed V. prasinus eating fruit(bananas) in captivity as has herpetologist and author, Robert G. Sprackland.^[14][13]

Reproduction

Clutches consist of up to five eggs, each weighing 10.5–11.5 grams (0.37–0.41 oz) and measuring about 2 by 4.5 centimetres (0.79 × 1.8 in). As many as three clutches are laid throughout the year; captive clutches have been laid in January, March, April, November, and December. The female emerald tree monitor lays her eggs in arboreal termite nests.^[12] The eggs hatch between 160–190 days, typically from June to November after which the young eat the termites and the termite's eggs within minutes of hatching.^[12] Sexual maturity is reached in about two years.^[5]

References

1. ^ "Varanus prasinus". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=174115. Retrieved 28 August 2008. 
2. ^ ^{a b c} Wilson, Don W.; Burnie, David (2001). Animal. London: DK. p. 422. ISBN 0-7894-7764-5. 
3. ^ 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 0-8120-9696-7. 
4. ^ Bennett, D. (1995). A Little Book of Monitor Lizards. Aberdeen, U.K.: Viper Press. 
5. ^ ^{a b} King, Ruth Allen; Pianka, Eric R.; King, Dennis (2004). Varanoid Lizards of the World. Bloomington: Indiana University Press. pp. 225–229. ISBN 0-253-34366-6. 
6. ^ 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
7. ^ Ziegler, T., A. Schmitz, A. Koch and W. Böhme (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
8. ^ Ciofi, Claudio. "The Komodo Dragon". Scientific American. http://www.sciam.com/article.cfm?id=the-komodo-dragon. Retrieved 2006-12-21. 
9. ^ ^{a b} Pianka, Eric R. (2006). Lizards: Windows to the Evolution of Diversity. Berkeley: University of California Press. p. 247. ISBN 0-520-24847-3. 
10. ^ ^{a b} Cogger, H. G. (2000). Reptiles & Amphibians of Australia, 6th edition. Sydney: Reed New Holland. p. 371. ISBN 1 876334 3 9. 
11. ^ Cogger, Harold; Zweifel, Richard (1992). Reptiles & Amphibians. Sydney: Weldon Owen. ISBN 0831727861. 
12. ^ ^{a b c d} 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. ISBN 9998057760. 
13. ^ ^{a b} Robert George Sprackland (1992). Giant lizards. Neptune, NJ: T.F.H. Publications. pp. 137–142. ISBN 0-86622-634-6. 
14. ^ Balsai, Michael (1997). The General Care and Maintenance of Popular Monitors and Tegus. BowTie. p. 6. ISBN 9781882770397. 

External links

• Photos at Biolib.cz
• Ozanimals.com
• Mampam.com