Roughneck monitor

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Rough-necked monitor
20230521 Varanus rudicollis.jpg
CITES Appendix II (CITES) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Varanidae
Genus: Varanus
Subgenus: Soterosaurus
Species:
V. rudicollis
Binomial name
Varanus rudicollis
(Gray, 1845) [3]

The black rough-necked monitor (Varanus rudicollis) 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 [4] It is sometimes known simply as the roughneck monitor. [5] In Thailand is called h̄èā cĥāng (Thai : เห่าช้าง; "elephant bark/roar"). [6]

Contents

The habitat of Varanus rudicollis is limited to primary and secondary rainforest and mangrove swamps. [7] In the wild the black rough-necked monitor is very rarely seen, but whether this is because of its rarity or its very secretive behavior is uncertain. [3] They are often kept successfully in captivity, but have a shy disposition. [3] [8]

This species is most closely related to its sister group, the water monitor species complex (e.g., the Asian water monitor) which are also in the subgenus Soterosaurus , having split from them 14 million years ago in the middle Miocene. [9] [10]

Description

Hatchling Varanus rudicollis 8 days old copy.png
Hatchling

The black roughneck is a medium to large monitor. It usually reaches an average adult size of 3–4 ft. (90–120 cm), with a maximum length of 5 feet (150 cm), reported. [8] The black rough-necked monitor can be easily recognized by large pointed scales adorning the necks of adults. [4] They are a gracile, long-bodied lizard with a prominently pointed snout. Black roughnecks are known for their very calm temperament, rarely biting or tail whipping in captivity. When threatened they prefer to escape, urinate or defecate, puff up their throats or “go necrotic” by closing their eyes as if playing dead.

Diet habits

Adult male Adult male Varanus rudicollis.png
Adult male

The dietary habits of black rough-necked monitors have been the subject of various studies. Early research by Schnider (in Werner 1900) found insects in specimen from Sumatra. Mertens (1942) suggested that ants and possibly termites were a significant part of their diet, collected using their tongue. Auffenberg (1988) supported this by discovering termites, large stick insects, and tree centipedes in specimens from Malaysia. Brandenberg (1983) found a stomach full of large cockroaches and grasshoppers in one individual, while another from Surat Thani in Thailand had a stomach full of crabs (Nabhitabhata, pers. comm.). Further research by Losos and Greene (1988) revealed that the diet of V. rudicollis may include frogs and their eggs, spiders, scorpions, crabs, cockroaches, beetles, and orthopterans. [11]

These monitors may remain active throughout the year, with their presence most noticeable during months of heavy rainfall

Lifespan

The known lifespan of black rough-necked monitor is about 10–20 years in captivity. [8]

References

  1. "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  2. Phimmachak, S.; Cota, M.; Grismer, L.; Quah, E.; Iskandar, D.; Wogan, G.; Arida, E. (2021). "Varanus rudicollis". IUCN Red List of Threatened Species . 2021: e.T83778529A83778660. Retrieved 19 November 2021.
  3. 1 2 3 "Monitor-lizards.net". Archived from the original on 2010-05-19.
  4. 1 2 "Indonesiatraveling.com".
  5. JCVI.org
  6. "อ.เจษฎา เร่งแจง เห่าช้าง เป็นสัตว์กลุ่มตะกวด ไม่ใช่งู-ไม่มีพิษ". Kapook.com (in Thai). 12 June 2015. Retrieved 16 June 2016.
  7. Mampam.com
  8. 1 2 3 "Herpcenter.com". Archived from the original on 2009-10-31.
  9. Welton, Luke J.; Wood, Perry L.; Oaks, Jamie R.; Siler, Cameron D.; Brown, Rafe M. (2014-05-01). "Fossil-calibrated phylogeny and historical biogeography of Southeast Asian water monitors (Varanus salvator Complex)" . Molecular Phylogenetics and Evolution. 74: 29–37. doi:10.1016/j.ympev.2014.01.016. ISSN   1055-7903. PMID   24486878.
  10. 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, doi:10.1101/2020.02.02.931188 , retrieved 2024-05-18
  11. Daniel Bennett. 1995. A Little Book of Monitor Lizards. Viper Press U.K.

Further reading