Oenpelli python

The Oenpelli python, known in binomial nomenclature as Simalia oenpelliensis, formerly Morelia oenpelliensis, is a species of large snake in the family Pythonidae. The species is endemic to the sandstone massif area of the western Arnhem Land region in the Northern Territory of Australia.[4] There are no subspecies that are recognised as being valid.[5] It has been called the rarest python in the world.[6][7][8] Two notable characteristics of the species are the unusually large size of its eggs and its ability to change colour.[9]

Oenpelli python
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Pythonidae
Genus: Simalia
S. oenpelliensis
Binomial name
Simalia oenpelliensis
(Gow, 1977)[1]
  • Python oenpelliensis
    Gow, 1977
  • Morelia oenpelliensis
    H.G. Cogger, Cameron &
    H.M. Cogger, 1983
  • Australiasis oenpelliensis
    Wells & Wellington, 1984
  • Nyctophylopython oenpelliensis
    — Wells & Wellington, 1985
  • M[orelia]. oenpelliensis
    Kluge, 1993[2]
  • Simalia oenpelliensis
    Reynolds et al., 2014[3]

Taxonomy and etymology

The Oenpelli python was first described in 1977 by Graeme Gow, who placed it in the genus Python.[1] It was then categorised by Cogger and Cameron as a species of Morelia.[10] In 2014, a work by Reynolds, Niemiller, and Revell proposed to classify it as Simalia.[11] The specific name, oenpelliensis, is derived from the type locality, which is given as "6.5 km S.W. of Oenpelli, Northern Territory, Australia (12°21'S, 133°01'E)".[2][12]


A large and rare species of Simalia (or Morelia), the Oenpelli python may grow to more than 4 m (13 ft) in length,[13] and one specimen in captivity is reportedly more than 5 m (16 ft) long.[14] It is unusually thin in proportion to its length, relative to other pythons.[9]

The dorsal colour pattern is dark olive-brown with darkened blotches. The belly is pale and dull, varying from cream to yellow.[4]

The Oenpelli python is able to change its skin colouration, which tends to be lighter at night and darker in the daytime.[9]

The eggs of the Oenpelli python have been described as "huge".[15] At 110.5 by 60 mm (4.35 by 2.36 in), they are almost twice the size of those for the related amethystine python (Simalia amethystina), which are reported as 70–98 by 45–56 mm (2.8–3.9 by 1.8–2.2 in).[15]


The Oenpelli python is nocturnal and inhabits rock crevices, trees, and caves.[9]

It feeds on birds in fruiting trees, and has been speculated to specialise in eating birds.[9] Adults prey on medium-to-large mammals, such as possum or large macropods.[4] Captive specimens eat birds and rodents.[9]

It is an ambush predator that remains motionless for long periods.

Distribution and habitat

The species, Simalia oenpelliensis, occurs in a restricted range in the Northern Territory, in the sandstone outcrops of western Arnhem Land.[4][10]

The species is found in habitat located on a sandstone massif, in the regions surrounding the upper reaches of the Cadell, South Alligator and East Alligator rivers. It is territorial, roaming between discrete positions, such as overhangs and caves in sandstone gorges or in a shady tree. Sightings are also reported in the region's woodland, heathland, and open rocky plains. It is noted as having an association with the Kombalgie sandstone gorges.[10] It is said to be associated with sandstone rock outcrops with dense vegetation.[9]

Conservation status

The total population of S. oenpelliensis is poorly surveyed, and no study has been made of the rate of its decline. This is partly due to the inaccessibility of the region, a factor that may help the preservation of the species. The conservation status of Morelia oenpelliensis is listed by the Northern Territory Government as vulnerable to extinction. This has been evaluated by known threatening factors, such as altered land use and fire regimes, and population inferred from the relative abundance of its prey. This is estimated to be below 10,000, which is inferred from several factors. As a large predator, the species is particularly vulnerable to declines in available prey. These larger mammals are more susceptible to changes in land use and threats such as introduced species. Suitable habitat is also limited in the distribution range of the species. The species is known to be illegally collected for private use, which is likely to impact on some subpopulations. This threat is limited by the inaccessibility of its habitat, the same factor that has restricted study of the species. Variation and decline in subpopulations has not been fully evaluated. It is found within a conservation reserve known as Kakadu National Park.[4]

An attempt to start a breeding program was begun in 2012[8] and has had some limited success.[14] As of July, 2014, the program included six specimens.[14] In early 2015, the first two captive-bred neonates were born.[13]

In Aboriginal language and culture

In the Kunwinjku language spoken in Oenpelli itself (now known as Gunbalanya), the python is called nawaran.[16]

See also


  1. Gow, G. F. (1977). "A New Species of Python from Arnhem Land". Australian Zoologist 19: 133-139. (Python oenpelliensis, new species)
  2. McDiarmid, R. W.; Campbell, J. A.; Touré, T. (1999). Snake Species of the World: A Taxonomic and Geographic Reference. Volume 1. Washington, District of Columbia: Herpetologists' League. ISBN 1-893777-01-4.
  3. "Simalia oenpelliensis ". The Reptile Database. www.reptile-database.org.
  4. Woinarsk, J. "Oenpelli python. Morelia oenpelliensis" (PDF). Threatened Species of the Northern Territory. Northern Territory Government. Archived from the original (PDF) on 2008-09-03. Retrieved 2008-10-22.
  5. "Morelia oenpelliensis ". Integrated Taxonomic Information System. Retrieved 2007-09-19.
  6. Rarest Python in the World. SnakeBytesTV. 18 December 2013. Retrieved 2016-02-04.
  7. Breeding plan aims to save snakes. ABC News (Australia). 29 March 2012. Retrieved 2016-02-04.
  8. Smith, D. (20 June 2012). "Snakes alive – if only he'd been seeing double". Sydney Morning Herald. Retrieved 2016-02-09.
  9. Murphy, J. C. "The Oenpelli Python, Simalia oenpelliensis". Giant Constricting Snakes – The Science of Large Serpents. Retrieved 2016-02-29.
  10. Cogger, H. G. (2000). Reptiles and Amphibians of Australia. New Holland Publishers Australia. ISBN 9781876334338.
  11. Reynolds, R. G.; Niemiller, M. L.; Revell, L. J. (2014). "Toward a Tree-of-Life for the boas and pythons: Multilocus species-level phylogeny with unprecedented taxon sampling" (PDF). Molecular Phylogenetics and Evolution. 71: 201–213. doi:10.1016/j.ympev.2013.11.011. Retrieved 2016-03-02.
  12. Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Morelia oenpelliensis, p. 193).
  13. Fowler, J.; Hollister, J. (11 April 2015). "Oenpelli python". The Reptiles of Australia. Retrieved 2016-02-29.
  14. Hancock, D. (15 July 2014). "Saving the Oenpelli python". Australian Geographic. Retrieved 2016-02-29.
  15. Murphy, J. C.; Henderson, R. W. (1997). Tales of Giant Snakes: A Historical Natural History of Anacondas and Pythons. Krieger Pub. Co. pp. 37, 105. ISBN 0-89464-995-7.
  16. Garde, Murray. "nawaran". Bininj Kunwok dictionary. Bininj Kunwok Regional Language Centre. Retrieved 19 June 2019.
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