Australian amethyst python

Australian amethyst python
Australian amethyst python ( Simalia kinghorni )
Systematics
without rank: Toxicofera Subordination : Snakes (serpentes) Superfamily : Python-like (Pythonoidea) Family : Pythons (Pythonidae) Genre : Amethyst pythons ( Simalia ) Type : Australian amethyst python
Scientific name
Simalia kinghorni
( Stull , 1933)

The Australian amethyst python ( Simalia kinghorni , syn .: Morelia kinghorni ), also Kinghorn's python , belongs to the family of pythons (Pythonidae) and is placed in the genus of amethyst pythons ( Simalia ). It was only separated from the amethyst python as a separate species in 2000 . With secured lengths of over five meters, this slender python is by far the largest snake in Australia and at the same time one of the longest snakes in the world. The distribution area includes the tropical northeast of Australia and a few offshore islands of the Torres Strait . Here he lives in dense rainforest where he spends about half of the time in trees. The diet consists of a large number of different vertebrates that are adapted to the size of the python. Large individuals relatively often prey on small kangaroos , which can rarely weigh up to 10 kilograms. Australian amethyst pythons, like all species of the Pythonidae, lay eggs (oviparous) and belong to those species in which the females can increase the incubation temperature by trembling muscles.

description

anatomy

The Australian amethyst python is a slender, but still quite sturdy python. Its long tail is longer in males and makes up over 15% of the total length of these. The large head is clearly set off from the neck and is clearly broadened in adult females. The eyes are on the side of the head and are directed slightly forward. The rounded, semi-oval snout seen from above is longer in males than in females. The round nostrils sit at an angle between the top of the head and the side of the head.

Scaling

The rostral (snout shield), which is only moderately visible from above, has, like most other pythons, two deep labial pits . The nostrils are each positioned in the upper rear part of the large nasal (nasal shield). A clearly recognizable seam runs from the nostril to the rear edge of the shield. Towards the middle of the head, the nasals are separated by a pair of internasals (intermediate nasal shields ). From the tip of the snout along the midline of the top of the head, the internalsals are followed by a large, long front pair of prefrontalia (forehead shields). This usually has extensive contact with the simple large frontal (frontal shield) behind it . The rear pair of prefrontalia lies on the side of the anterior prefrontalia and is completely separated by it. Behind the frontal there are three pairs of large parietals (crown shields ). On the center line between these pairs of shields there may be one or two small interparietals ( shields between the apex ). Over the eyes is ever a large triangular Supraoculare (via eye shield). Preocularia (fore eye shields) exist two to three, postocularia (posterior eye shields) three to five. Subocularia (under eye shields) are absent in this species. On the side of the head between the eye and nostril there are 7 to 12 Lorealia (rein shields) arranged in one to three rows . Of the 12 to 14 supralabials (shields of the upper lip), the foremost four have deep labial pits on their rear edge, the size of the labial pits decreasing towards the angle of the mouth. Supralabials number 7 and 8 also touch the lower edge of the eye. Infralabialia (lower lip shields ) there are 20 to 24, of which the foremost two weakly recognizable, and from number 10 to 12 eight to nine lower lip shields have deep labial pits. The chin pit consists of shield-less skin or, rarely, a few small shields.

The number of ventralia (abdominal shields) varies between 328 and 344, the number of dorsal rows of scales in the middle of the body between 51 and 55. From the cloaca to the tip of the tail there are 108 to 116 mostly paired subcaudalia (underside shields of the tail). The anal (anal shield) is undivided.

coloring

Australian amethyst python

No unpatterned or axanthic color morphs are known of the Australian amethyst python . The basic body color is light brown and is lightened to white-gray on the stomach. A wide, irregular, dark brown to black transverse ligament runs along the spine and two irregular, partially interrupted dark brown to black longitudinal ligaments on each side. The back ligaments often connect to one another and also often fuse with the longitudinal ligaments of the flanks. On the back of the body towards the tail, the back ligaments are usually longer and stretch out onto the flanks, making the tail appear partially curled.

The top and side of the head correspond to the basic body color. Many of their shields are framed by a fine black line. Lips, chin and throat are white-gray. A dark band runs from the back of the eye over the upper edge of the shields of the upper lip to the corner of the mouth. A black neck band runs across the back of the head from corner to corner of the mouth. Often there is also a second, parallel back neck band or a simple neck patch. The iris of this amethyst python is golden.

Color change

The species shows a well-developed ontogenetic color change. Newly hatched young animals are brown and have a matt pattern. However, they already become reddish-brown after their first molt and their pattern is more contrasting. Australian amethyst pythons are also able to intensify or weaken their colors to a small extent over a period of about 24 hours under environmental influences. Even during the cool winter months and the gestation period, females generally become darker.

length

Australian amethyst pythons show a strong sexual dimorphism in terms of length and mass . Males reach sexual maturity with a head-trunk length of about 1.34 meters, while females only reach sexual maturity with a head-trunk length of about 2.27 meters. In contrast to many other pythons , the males of this species are often over a third longer and up to twice as heavy as females. 24 adult females were measured on the Tully, a river around 140 kilometers south of Cairns . These had an average head-torso length of 2.68 meters and a mass of 3.4 kilograms. At the same location, 80 adult males were found to have a mean head-torso length of 2.91 meters and a mass of 5.1 kilograms. Of these, the largest male had a head-torso length of 3.76 meters and a weight of 11 kilograms. A further study of fewer adults on the Atherton Tablelands gave very similar results.

In the past, length indications over 6 meters long individuals found their way into the literature, all of which are no longer verifiable today and are heavily doubted by Fearn & Sambono (2000), among others. The most extreme information comes from Worell, who in 1954 reported secondhand about an allegedly 8.5 meter long animal from Greenhill in Cairns, described it as 7.6 meters long in 1958 and mentioned it repeatedly in 1963 under the first length. He leaves it open whether the mass relates to a carcass or a skin that may have been stretched by more than 3 meters. Dean also describes an extremely large individual from the Barron Falls in 1954 with a total length of 7.2 meters, which, however, consisted of an artificially elongated carcass that had rotted for more than two days in the tropics. The largest female Australian amethyst python that has been seriously measured to date was caught in Palm Cove near Cairns in 2000 , had a total length of 5.65 meters, with 12 centimeters on the head and 75 centimeters on the tail, a circumference of 36 centimeters and one in the middle of the body Mass of 24 kilograms. The largest so far seriously measured male was discovered in Kuranda in 2002 , was a total of 5.33 meters long, of which the head was 11 centimeters and the incomplete tail 60 centimeters and weighed 17 kilograms.

distribution and habitat

Distribution area of ​​the Australian amethyst python (green), Tanimbar python (black), Halmahera python (violet), as well as the New Guinea (red, dark & ​​light orange, yellow) and Seram python (blue)

Its distribution area includes the tropical northeastern Australian mainland and several islands of the Torres Strait off the Cape York Peninsula . On the mainland, its occurrence extends from the tip of the Cape York Peninsula south along the coastal rainforest through the Atherton Tablelands , the forested eastern foothills of the Great Dividing Range , along the coast via Mount Spec to the Burdekin River south of Townsville . In 2004, an even more southerly population in the rainforest near Conway, south of Airlie Beach , was described. Exact information about the population size and any connections to more northern populations is not yet available. However, it is suspected to have been founded in 1990 by escaped adult animals from a local zoo and to have spread successfully since then.

The Australian amethyst python lives primarily in dense primary and secondary rainforests . He also lives in the bush forest, eucalyptus forest and hard- leaf vegetation. Occasionally it is also found in the tall grass of clearings and forest edges and apparently occasionally invades farmland and farms.

In the southern part of the distribution area the species does not seem to exceed the 1000 meter limit significantly. It lives on the Atherton Tablelands up to 900 meters above sea level. In the cooler southern part of its distribution, it seems mostly only to occur in forests with epiphytes . He particularly prefers spotted ferns of the species ( Drynaria rigidula ), less frequently also antler ferns of the species Platycerium bifurcatum , striped ferns ( Asplenium sp. ) And rattan palms of the genus Calamus . These plants, which also live on trunks and branches above the dark surface layer of the forest, form a favorable microhabitat against climatic fluctuations. The pythons can sunbathe on the trees during the day and don't have to leave them in the cool night.

behavior

Australian amethyst python on a tree in a epiphyte at Lake Barrine, Australia

Little is known about the behavior of this python. It is both ground ( terrestrial ) and tree-dwelling ( arboreal ), apparently almost half of the time being spent in trees. The species is primarily diurnal and often actively warms itself in the sun in the mornings in order to maintain an average body temperature of around 25 ° C during the day. On the Atherton Tablelands, this python mostly uses epiphytes with a minimum circumference of one meter, at a height of 17 to 40 meters, as a sunbathing and hiding place. Other hiding places above, in and below the surface layer of the forest are used much less often. While most animals evidently seek out new epiphytes again and again or alternate between different ones, the same can rarely be claimed over a period of at least two months.

At least in the southern parts of the distribution area, the forest habitat is adapted to the seasons. During the dry season, it is preferred to go to places near water, at the beginning of the rainy season the pythons exchange areas at risk of flooding for dry areas. In the cool months, they often climb tall trees to sunbathe above the shady forest vegetation. In winter they often even leave the dark, damp rainforest to warm to the sun-exposed forest edges. All of these habitat changes often take place on a relatively fixed territory. Of six adult Australian amethyst pythons, some of which were observed for more than two years, none claimed an area with a diameter of more than four kilometers. A tracking experiment on an individual with a total length of 3.3 meters has also shown that larger animals are able to cover at least 348 meters a day.

nutrition

Australian amethyst python devours a tiny kangaroo near Daintree National Park , Australia

The Australian amethyst python is one of Australia's largest native ground-dwelling predators. Its food spectrum consists of a large number of different vertebrates, especially birds and mammals. Including, for example Regenbogenspinte ( Merops ornatus ), bush rats ( Rattus fuscipes ), northern quoll ( Dasyurus hallucatus ), glasses flying foxes ( Pteropus conspicillatus ), Large short-nosed bandicoot ( Isoodon macrourus ), Large perameles ( Perameles nasuta ) and Large strips gatherers ( Dactylopsila trivirgata ). On the edge of settlements, the species also feeds on domestic fowl. Large individuals apparently also eat frequently juvenile relative and semi adult representatives fortified little kangaroo species, especially those of Flinkwallabys ( Macropus agilis ), red-legged pademelon ( Thylogale stigmatica ) and Bennett-tree-kangaroo ( Dendrolagus bennettianus ). One of the largest prey animals documented to date was a 10 kilogram adult agile wallaby that was devoured by a 4.33 meter long and 13.5 kilogram female python.

The species prefers the ambush , for which it sometimes adopts remarkably different lurking positions. In wooded areas, this python either lies in wait at the foot of trees that are well frequented by prey, positions itself with an S-shaped tense, hastily prepared front body on a horizontal branch close to the ground, or sits in the branches for hours with only its tail attached with an S-shaped neck hanging motionless over a wildlife trail. In more open areas on the edge of wildlife trails, occasionally even on the edge of roads with little traffic, these pythons anchor themselves with their tail or partly their entire rear body to a fixed object and, with their front body in an S-shape, adjust to prey animals running along the path. On areas with tall grass, Australian amethyst pythons even roll up tightly or loosely and erect their front body up to 60 centimeters vertically, like a branch. From this position they can spot prey better and align themselves with it at an early stage.

Reproduction

Typical colored hatchling of the Australian amethyst python

Very little is known about reproduction in the field either. At least in the south of the distribution area, courtship and mating take place during the rainy season. On the banks of the Tully, 140 kilometers south of Cairns, copulating couples have been observed in June and July. According to captivity observations, the partners lie stretched out next to each other during mating, which sometimes lasts 60 minutes and sometimes takes place repeatedly, with only their tails being wrapped around each other in the cloacal region. Often several large males gather around a receptive female. The presence of male competitors is usually tolerated, but there are seldom comment fights that can last over 30 minutes. For this purpose, two rivals erect their front bodies up to a meter, loop around each other and try to wrestle and bite each other. The deep bite wounds can have serious consequences, especially for smaller opponents, which is why they usually stay away from such accumulations. The increased chances of reproduction for large males was probably also a strong evolutionary reason for selection, which is why the species today shows such a pronounced sexual dimorphism. Pregnant females, at least in captivity, do not eat any food and show a pronounced behavior in the sun, which promotes the development of the eggs. They often lie with their stomach on their side or turned up. Field observations also show that females sunbathe much more frequently and for longer than males during this period.

In captivity, 7 to 20, on average 12, white-gray eggs are laid, which measure an average of 83 × 50 millimeters and weigh 100 grams. The clinging egg cluster is then surrounded and protected by the female. Through active muscle tremors, the female is also able to maintain a constant incubation temperature. The hatchlings in captivity after 78 to 106 days have an average total length of 65 centimeters and an average weight of 54 grams. The light brown colored and still very matt patterned young snakes shed their skin for the first time after one to two weeks. In captivity, these pythons grow very quickly. Males reach sexual maturity here after their first year of life, while females need around two years to do so.

Danger

At the beginning of the 20th century, the rainforest in Northeast Australia was cleared over a large area over decades in order to be able to farm. As a result, numerous habitats of the Australian amethyst python were isolated, restructured and destroyed, which led to a population decline. In 1988, the still remaining rainforest was as wet tropics of Queensland to the UNESCO World Heritage declared and since then no longer cleared. Although the population of the Australian amethyst python once had a significantly larger distribution area and a higher density, the populations in well-protected places are still partly high today. In the past, these pythons were often killed near settlements. Today, most of the locals realize that this snake is neither poisonous nor dangerous for humans and is therefore rarely killed , in stark contrast to poisonous snakes .

Systematics

The amethyst python was first described by Schneider in 1801 under the scientific name Morelia amethistina . In 1933, Stull assigned subspecies status to the Australian population as Morelia amethistina kinghorni . In 2000, Harvey et al. taking into account morphological, biogeographical and molecular genetic aspects, five distinct species: Morelia amethistina , Morelia kinghorni , Morelia nauta , Morelia clastolepis and Morelia tracyae . All of the amethyst pythons described so far inhabit spatially separated habitats ( allopatry ). It is assumed, however, that further species can be differentiated among the species described so far, some of which even inhabit the same areas ( sympatry ). This is particularly suspected in New Guinea and New Ireland .

It is believed that an ancient form of the amethyst python once lived on the emerging New Guinea. Millions of years ago, in a first phase, the islands of Halmahera and New Ireland separated from New Guinea by deep straits, which completely isolated the amethyst python populations there. During later ice ages , land bridges formed between New Guinea and neighboring islands as well as the Australian mainland due to the low sea level. In a second phase, amethyst pythons colonized the D'Entrecasteaux Islands , the Louisiade archipelago and Aru . Seram , Ambon , Yapen , the coastal islands of the Torres Strait and Northern Australia. In a third phase, these pythons were able to use driftwood to get from Aru to the neighboring island of Kai , and those from Yapen to the neighboring island of Biak . The Tanimbar Islands also never had contact with other land masses, which means that precursors of this population must also have colonized the islands by water. Since New Guinea also changed significantly geotectonically, the original form of the amethyst python could still differentiate itself locally.

These pythons are most closely related to the Boelen python ( Morelia boeleni ). The characteristic commonality of amethyst and Boelen pythons is the presence of at least two pairs of large apex shields. In 1984, Wells & Wellington proposed separating amethyst pythons from diamond pythons ( Morelia ) as an independent genus called Australiasis .

The genus name Australiasis is invalid, however, because the genus was described in a journal that does not carry out a peer review process. At the beginning of 2014, the generic name Simalia (Gray, 1849) was therefore introduced for a new genus composed of the Boelen python, the Oenpelli python and the amethyst pythons.

According to Harvey et al. (2000) and Reynolds et al. (2014) as follows:

Simalia	Oenpelli python ( Simalia oenpelliensis )     Boelen python ( Simalia boeleni )     Halmahera python ( Simalia tracyae )     “ Simalia amethistina ” (New Ireland)     “ Simalia amethistina ” (Northwest New Guinea)     Seram python ( Simalia clastolepis )     Australian amethyst python ( Simalia kinghorni )     Tanimbar python ( Simalia nauta )     “ Simalia amethistina ” (Southwest New Guinea)

The Australian amethyst python received the specific epithet kinghorni in honor of the Australian herpetologist and ornithologist James Roy Kinghorn, its scientific name Simalia kinghorni . Morphologically, the Australian amethyst python differs only slightly from the New Guinea amethyst python population in southwest New Guinea. At the genetic level, however, the two species show clear differences and must therefore have evolved away from each other for a long time. Among the amethyst python species living today, they are not even the closest related.

literature

• MB Harvey, DG Barker, LK Ammerman, PT Chippindale: Systematics of Pythons of the Morelia amethistina Complex (Serpentes: Boidae) with the Description of three new Species . Herpetological Monographs 14, 2000, pp. 139-185.

Web links

• Simalia kinghorni in The Reptile Database

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m n} S. Fearn, L. Schwarzkopf, R. Shine: Giant snakes in tropical forests: a field study of the Australian scrub python, Morelia kinghorni . Wildlife Research 32, 2005, pp. 1-9. doi : 10.1071 / WR04084
2. ↑ ^{a b c d e f g} A. Freeman, A. Freeman: Habitat Use in a Large Rainforst Python (Morelia kinghorni) in the Wet Tropics of North Queensland, Australia . Herpetological Conservation and Biology 4, Issue 2, 2009, pp. 252-260, online, pdf
3. ↑ ^{a b c d e f g h i j k l} M. B. Harvey, DG Barker, LK Ammerman, PT Chippindale: Systematics of Pythons of the Morelia amethistina Complex (Serpentes: Boidae) with the Description of three new Species . Herpetological Monographs 14, 2000, pp. 139-185.
4. ↑ ^{a b c d e f g h i} O. G. Stull: Two new subspecies of the family Boidae . Occasional Papers of the Museum of Zoology, University of Michigan 267, 1933, pp. 1-4, online, pdf
5. ↑ ^{a b c d e f g h i} S. B. McDowell: A catalog of the snakes of New Guinea an the Solomons, with special reference to those in the Bernice P. Bishop Museum. Part II. Anilioidea and Pythoninae . Journal of Herpetology 9, 1975, pp. 1–79. (Based on the localities described, species-specific data were taken as far as possible that apply to today's Morelia kinghorni )
6. ↑ ^{a b c d e f} A. Freeman, C. Bruce: The Things You Find on the Road: Roadkill and Incidental Data as an Indicator of Habitat Use in Two Species of Tropical Pythons . In: RW Henderson, R. Powell (Eds.): Biology of the Boas and Pythons . Eagle Mountain Publishing Company, Eagle Mountain 2007, ISBN 978-0-9720154-3-1 , pp. 153-165.
7. ↑ SL Fearn, J. Sambono: A reliable size record for the Scrub Python Morelia amethistina (Serpentes: Pythonidae) in north east Queensland . Herpetofauna 30, 2000, pp. 2-6.
8. ^ SL Fearn: Notes on a maximally sized Scrub Python Morelia amethistina (Serpentes: Pythonidae) from Kuranda, North East Queensland . Herpetofauna 32, 2002, pp. 2-3.
9. ^ ^{A b} S. L. Fearn, D. Trembath: Southern distribution limits and a traslocated population of scrub python Morelia kinghorni (Serpentes: Pythonidae) in tropical Queensland . Herpetofauna 36, ​​No. 2, 2006, pp. 85-87.
10. ↑ ^{a b} J. Augusteyn: Southerly range extension for the amethystine python Morelia kinghorni (Squamata: Boidae) in Queensland . Memoirs of the Queensland Museum 49, issue 2, 2004, p. 602, online, pdf
11. ↑ ^{a b c d e} L. Sues, R. Shine: Morelia amethistina (Australian Scrub Python). Male-Male Combat . Herpetological Review 30, No. 2, 1999, p. 102.
12. ↑ ^{a b} R. W. Martin: Field Observation of Predation on Bennett's Treekangaroo (Dendrolagus bennettianus) by an Amethystine Python (Morelia amethistina) . Herpetological Review 26, No. 2, 1995, pp. 74-76
13. ↑ ^{a b} S. L. Fearn, J. Sambono: Some ambush predation postures of the Scrub Python Morelia amethistina (Serpentes: Pythonidae) in north east Queensland . Herpetofauna 30, 2000, pp. 39-44.
14. ^ S. Fearn: Morelia amethistina (Scrub Python). Diet . Herpetological Review 33, No. 1, 2002, pp. 58-59
15. ^ N. Charles, R. Field, R. Shine: Notes on the Reproductive Biology of Australian Pythons, Genera Aspidites, Liasis and Morelia . Herp Review 16, Issue 2, 1985, pp. 45-48, online, pdf
16. ^ RW Wells, CR Wellington: A classification of the Amphibia and Reptilia of Australia . Australian Journal of Herpetology, Supplementary Series, Issue 1, 1984 pp. 1–61, full text  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.  
17. ↑ Hinrich Kaiser, Brian I. Crother, Christopher MR Kelly, Luca Luiselli, Mark O´Shea, Hidetoshi Ota, Paulo Passos, Wulf D. Schleip, Wolfgang Wüster: Best Practices: In the 21st Century, Taxonomic Decisions in Herpetology are Acceptable Only When Supported by a Body of Evidence and Published via Peer Review. In: Herpetological Review, 2013, 44 (1), 8–23 .. 44, 2013, pp. 8–23.
18. ^ R. Graham Reynolds, Matthew L. Niemiller, Liam J. Revell: Toward a Tree-of-Life for the boas and pythons: Multilocus species-level phylogeny with unprecedented taxon sampling. Molecular Phylogenetics and Evolution, Volume 71, February 2014, Pages 201-213, doi: 10.1016 / j.ympev.2013.11.011