Banded water cobra
| Banded water cobra | ||||||||||||
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Banded water cobra ( Naja annulata ) |
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| Well annulata | ||||||||||||
| Peters , 1876 |
The banded water cobra ( Naja annulata , Syn .: Boulengerina annulata ) is a species of snake from the family of poisonous snakes (Elapidae). It counts within the genus of the real cobras ( Naja ) to the subgenus Boulengerina , which was previously listed as an independent genus.
features
Naja annulata reaches a total length between 150 and 210 cm, rarely up to 270 cm. The physique is strong. The head is flat, relatively short and hardly separates from the neck. The eyes are small and have a round pupil. The body has a yellow-brown to brown on the upper side, darker towards the tail and is marked with cross bars. The ventral side is yellowish-white. As is typical for venomous snakes, the venom apparatus consists of venom glands located on the side of the skull (specialized salivary glands ) and immobile fangs located in the anterior upper jaw (proteroglyphic tooth position).
Subspecies
There are two subspecies :
- Naja annulata annulata B UCHHOLZ & P ETERS 1876 ( nominate form ); Upper side of the body 21 to 24 close-fitting cross bars.
- Naja annulata stormsi (D OLLO 1886); three to five black bars on the neck, the first two ring-like around the body. On the middle of the back, dark spots can be seen at relatively even intervals.
Pholidosis
The pholidosis (scaling) shows the following characteristics:
- 6 to 7 upper lip shields ( supralabials ),
- 7 to 8 lower lip shields ( sublabials ),
- 23 rows of smooth trunk scales ( Scuta dorsalia ),
- 192 to 195 abdominal shields ( scuta ventralia ) in N. a. stormsi .
distribution
The distribution area includes regions in Cameroon , Gabon , Democratic Republic of the Congo , Republic of the Congo , Central African Republic , Tanzania , Equatorial Guinea , Rwanda , Burundi , Zambia and Angola . Habitats close to water, such as rocky banks of rivers and lakes in wooded surroundings or savannas, are populated.
Way of life
The banded water cobra leads a day and nocturnal lifestyle and is often in the water. She can dive up to 25 meters deep and for 10 minutes. She finds hiding places in crevices at the edge of the water. The range of prey includes fish and amphibians . The species is not aggressive towards humans; if threatened it quickly flees into the water. Driven into a corner, she straightens the front body and flattens it sideways. The hat is narrow. The propagation is done by oviparity so oviparous.
Snake venom
The poison secretion of the water cobra contains postsynaptic neurotoxins . Short neurotoxin 1, a three-finger toxin , binds to postsynaptic acetylcholine receptors and blocks neurotransmission . In animal experiments , a mean lethal dose of 0.052 mg / kg ( intraperitoneally ) for this toxin could be determined. After a poison bite in humans, mild local symptoms at the bite site and unspecific general symptoms (e.g. headache, dizziness, nausea, vomiting) can be assumed. The neurotoxins cause symptoms of paralysis , which can initially be noticeable as ptosis and then change into flat paralysis . The death is through a peripheral respiratory paralysis occur. Due to the pronounced escape behavior, there are hardly any encounters with humans or poisonous bites.
Measures after poison bite
After a poisonous bite, a pressure bandage can be applied to the bitten limb as a first aid measure to slow down the spread of toxins in the body. Those affected should not move as much as possible and should be transported to a hospital lying down. Monitoring takes place for at least 24 hours. If neurotoxic symptoms occur, symptomatic treatment should be carried out. Artificial ventilation is indicated if necessary . The effect of the neurotoxins is reversible. A specific antivenin is not available.
Individual evidence
- ↑ a b c d e University of Adelaide, Clinical Toxinology Resources: ( Naja annulata ) (accessed June 26, 2018).
- ↑ UniProt: ( Short neurotoxin 1, Naja annulata ) (accessed June 26, 2018).
literature
- Ludwig Trutnau: Snakes in the terrarium. Volume 2: Venomous Snakes. Verlag Ulmer, Stuttgart 1998, ISBN 3-800-1705-23 .
