Taipane
| Taipane | ||||||||||||
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Inland taipan ( Oxyuranus microlepidotus ) |
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| Scientific name | ||||||||||||
| Oxyuranus | ||||||||||||
| Kinghorn , 1923 |
Taipane ( Oxyuranus ) are a species of snakes from the family of poisonous snakes (Elapidae) common in Australia and Papua New Guinea . One of the three species ( O. temporalis ) was only described in 2007 on the basis of a specimen found in 2006, so very little information is available for this species. The species have an extremely potent, neurotoxic and blood coagulation disruptive poison; however, due to their fear of humans and the remote habitats of two of the three species, taipans are of little medical relevance.
features
anatomy
Taipans are large to very large venomous snakes. The head-body length of adult individuals is 78.3 to 226.0 cm, at O. scutellatus the tail reaches 19 to 20% of the head-body length, while previously only known specimen of O. temporalis 14.8%. Taipane are the largest poisonous snakes in Australia. The animals are slender, the head is large, rectangular and clearly set off from the relatively slender neck. The sexes do not differ in terms of size and color.
Scaling
Like all venomous snakes, Taipans have nine large, symmetrical shields on the top of their heads. The animals have one or two primary temporalia and six or seven infralabiala , subocularia absent. The dorsal scales are smooth or slightly keeled. The number of ventral scales ( ventral shields ) varies between 211 and 250, the number of divided subcaudalia between 45 and 80. The anal shield is undivided. The animals have 21-25 dorsal rows of scales in the middle of the body.
coloring
The basic color of the top is variable light brown, dark brown, red brown, copper red or olive. The Taipan shows no drawing on this basic color, the Inland Taipan shows a narrow, dark banding, especially in the rear half of the body. The head is clear in the Taipan, only weakly or not at all brightened in the Inland Taipan. The underside is whitish in the Taipan, yellow in the Inland Taipan.
distribution and habitat
The genus occurs in Australia and New Guinea. The range of the taipan includes coastal regions from eastern to northern Australia and Papua New Guinea . The species inhabits tropical savannahs and forests there with annual rainfall over 800 mm. The other two species are restricted to the interior of Australia and colonize very dry semi-deserts with annual rainfall below 300 mm.
Systematics
The genus includes three species, one of which ( O. temporalis ) was only described in 2007:
- Taipan ( Oxyuranus scutellatus ) with two subspecies Oxyuranus scutellatus scutellatus and Oxyuranus scutellatus canni
- Inland taipan ( Oxyuranus microlepidotus )
- Oxyuranus temporalis
The closest relatives of Taipan are the pseudonaja ( pseudo Well ).
Way of life
Taipan and inland taipan are predominantly diurnal, and the only known specimen of O. temporalis was found active during the day. As far as known, all species are ground-dwelling.
nutrition
In contrast to all other poisonous snakes in Australia, Taipans feed exclusively on warm-blooded ( homoiothermal ) animals. Up to now, gastric examinations have shown almost exclusively mammals as prey, only once a bird. The range of mammals captured is very broad and includes both rodents and small marsupials up to the size of rats ( Rattus sp.). Even young individuals evidently only eat homoithermal animals; reptiles and amphibians were ignored in captivity. The prey is actively sought, Taipans use their olfactory and apparently excellently trained sense of sight. The prey is bitten at lightning speed and released again immediately. Together with the extremely effective poison, this is an adaptation to the very defensive prey, which could otherwise endanger the snake. The prey is consumed when it is dead or immobile.
Reproduction
All species lay eggs (oviparous). Females with eggs in their bodies were found from August to November, and eggs were laid from September to March. According to field and housing observations, the clutches comprise 7 to 20 eggs. In captivity, the juvenile snakes hatch after 64–69 days, when they hatch they have head-trunk lengths of 30–34 cm.
Behavior towards people
The Taipan is very shy and avoids people at an early stage due to his very good sense of sight. Encounters between humans and inland taipans are extremely rare; the species was not rediscovered until 1967 after it was first described in 1879. Both species only bite when suddenly confronted with humans or cornered. In these cases the animals fight back vehemently and often bite repeatedly.
Poison
effect
The poison is primarily neurotoxic , but also has components that disrupt blood clotting. The neurotoxin blocking presynaptic the signal transfer on the muscles, thus causing paralysis. The average amount of poison per bite is given as 44–120 mg dry weight. The poison of the Taipane is extremely effective, the LD 50 value in mice is 0.064 (Taipan) or 0.010 mg per kg body weight (domestic Taipan). As far as is known, inland taipan is the snake species with the most potent venom of all.
Due to the large amount of poison and the high toxicity, the bite in humans is usually fatal if left untreated. The bite is often not noticed and local symptoms in the area of the bite site are often absent. Typical symptoms of a bite are initially nausea and vomiting, then progressive paralysis of the muscles up to fatal respiratory failure without treatment and blood clotting disorders. A 4-year-old child apparently bitten several times by a taipan died about an hour after the bites. A 39-year-old man ceased to breathe about 7-10 hours after the bite. The man was given artificial respiration for 19 days and was discharged after 27 days.
Epidemiology
Despite their extreme toxicity, taipans are described as hardly relevant from a medical point of view due to their shyness, and bite accidents are apparently very rare. The inland taipan and O. temporalis also live in regions that are hardly populated by humans. For inland taipan, only four bite accidents were known up to 1990, one of which involved a herpetologist catching an animal and a second a keeper in a laboratory for antisera; both bite victims survived.
swell
Individual evidence
- ↑ Doughty, P., B. Maryan, SC Donnellan and MN Hutchinson: A new species of taipan (Elapidae: Oxyuranus) from central Australia. Zootaxa 1422, 2007: pp. 45-58.
- ↑ Shine, R. and J. Covacevich: Ecology of Highly Venomous Snakes: the Australian Genus Oxyuranus (Elapidae). Journal of Herpetology 17, Issue 1, 1983: p. 63
- ↑ Mirtschin, PJ, GR Crowe and R. Davis: Dangerous Snakes Of Australia. In: P. Gopalakrishnakone, LM Chou: Snakes of Medical Importance. Venom and Toxin Research Group, National University of Singapore, 1990: 80-81 and 89.
- ↑ Mirtschin, PJ, GR Crowe and R. Davis: Dangerous Snakes Of Australia. In: P. Gopalakrishnakone, LM Chou: Snakes of Medical Importance. Venom and Toxin Research Group, National University of Singapore, 1990: 83-85
- ↑ Mirtschin, PJ, GR Crowe and R. Davis: Dangerous Snakes Of Australia. In: P. Gopalakrishnakone, LM Chou: Snakes of Medical Importance. Venom and Toxin Research Group, National University of Singapore, 1990: pp. 90-91
literature
- Doughty, P., B. Maryan, SC Donnellan, and MN Hutchinson: A new species of taipan (Elapidae: Oxyuranus) from central Australia. Zootaxa 1422, 2007: pp. 45-58.
- Mirtschin, PJ, GR Crowe, and R. Davis: Dangerous Snakes Of Australia. In: P. Gopalakrishnakone, LM Chou: Snakes of Medical Importance. Venom and Toxin Research Group, National University of Singapore, 1990: pp. 1-174. ISBN 9971-62-217-3
- Shine, R. and J. Covacevich: Ecology of Highly Venomous Snakes: the Australian Genus Oxyuranus (Elapidae). Journal of Herpetology 17, Issue 1, 1983: pp. 60-69.
