Naja snake

Naja snake

A genus of poisonous elapid snakes called cobras is called Naja ("true cobras"). The most common and most frequently regarded "genuine" cobras are those belonging to the genus Naja. Regions in Africa, Southwest Asia, Southern Asia, and Southeast Asia are home to a variety of species. The king cobra (Ophiophagus megan) or the rinkhals (Hemachatus haemachatus), two other elapid species that are also referred to as "cobras," are not true cobras because they do not fall under the umbrella of the genus Naja. They are instead members of the monotypic phyla Hemachatus (rinkhals) and Ophiophagus (king dragons).

The number of species in the genus Naja once ranged from 20 to 22, but sources now differ widely as a result of recent taxonomic changes.

 However, there is substantial support for a 2009

Etymology

This genus name derives from the Sanskrit word naga, which means "snake" (with a hard "g"). Although it is doubtful, some [who?] claim that the Sanskrit term is cognate with the English word "snake," Germanic: *snk-a-, Proto-IE: *(s)ng-o-, Mayrhofer labels this etymology "unglaubhaft," or "not trustworthy," and offers a more logical connection between it and the Sanskrit word nagna, which means "hairless, naked."

Description

The majority of naja species have relatively slim bodies and come in a variety of lengths. The majority of species can grow to 1.84 meters in length (6.0 ft). The forest cobra is arguably the longest species of cobra, with some of the larger animals reaching maximum lengths of over 3.1 m (10 ft). To make themselves appear larger to a potential predator, all may raise their front quarters off the ground and flatten their necks. All species, with the exception of the Indian cobra (Wirklich naja) and Lake cobra (Naja oxiana), have some degree of adaption to spitting. The Fang form is diverse.

Venom

All genera of Naja are capable of biting a person fatally. The majority of species have venom that is highly neurotoxic and affects the nervous system, paralyzing victims. However, many of these species also have cytotoxic characteristics that cause swelling and necrosis as well as severe anticoagulant effects. Some snakes' venom also contains cardiotoxic elements.

Several Naja species, also known as spitting cobras, have a specialized venom delivery system in which their front fangs have a shortened, rounded opening in the front surface that ejects the venom forward, out of the mouth, as opposed to ejecting it downward through an elongated discharge orifice (similar to a hypodermic needle). Although it is frequently called "spitting," the action is more akin to squirting. The flexibility and precision with which they

According to a recent study, all three lineages of spitting cobras have evolved stronger pain-inducing abilities due to elevated phospholipase A2 levels, which enhance the analgesic effects of the cytotoxins found in most cobra venoms. Spitting first appeared in African and Asian Naja around the same time as the human species' chimpanzee evolutionary lineages split apart in Africa and Homo erectus arrived in Asia. Therefore, the scientists speculate that the appearance of bipedal device primates may have sparked the evolution of cobra spitting.

The most poisonous Naja species is the Caspian cobra (N. oxiana), which is found in Central Asia. According to Brown (1973), the mouse LD99-100 subcutaneous value is 0.4 mg/kg . However, Ernst and Zug et al. list a range for the LD50 of 0.09 mg/kg to 0.21 mg/kg SC and 0.037 mg/kg IV.A subcutaneous value of 0.2 mg/kg was listed by Latifi (1984).The Subcutis LD50 in lab mice was 0.078 mg/kg in a different investigation in which venom was obtained from a variety of specimens in Iran. This was the most potent Naja venom by this way of envenomation. The crude venom of N. oxiana caused an individual case of intracerebroventricular injection poisoning to result in the lowest known lethal dose (LCLo) of 0.005 mg/kg, the lowest among all cobra species ever documented.

From a medical perspective, due to the quantity of bites and fatalities they cause throughout their geographic range, the Naja species constitute a significant category of snakes from a medical perspective. They are spread widely across the continents of Africa (including some Saharan regions where Naja haje can be found), Southwest Asia, Central Asia, South Asia, East Asia, and Southeast Asia. The majority of bites from some cobra species—roughly 30%—are dry bites that do not result in venomous bites (a dry bite is a bite by a venomous snake that does not inject venom).

The disparities in mortality rates among several species within the same genus are influenced by a variety of factors. Cobra bites can have a fatal effect on both treated and untreated victims, and these cases can occur relatively frequently. As an illustration, the death rates for untreated instances of Significant factors that affect the variance in fatality rates among cobra-envenomated victims are the severity of the bite and the species of cobra that envenomated the victim. According to LD50 testing on mice, the Caspian cobra (N. oxiana) and the Philippine cobra (N. philippinensis) are the two cobra species with the most poisonous venom. Both species show significant neurotoxicity and a series of potentially fatal symptoms after being envenomated. Death has been recorded in cases of either species' envenomation in as little as 30 minutes. Patients respond very well to antivenom therapy if it is administered immediately after envenomation. The only neurotoxic venom produced by N. philippinensis is observable neurotoxic with negligible pain and limited tissue damage. oxiana envenomation is substantially more complicated. The venom of this species also contains very potent cytotoxic and cardiotoxic components in addition to notable neurotoxicity. In every incidence of envenomation, the local symptoms are distinct and obvious: excruciating pain, excruciating swelling, bruising, blistering, and tissue necrosis. Although they are uncommon and secondary, renal injury and cardiotoxicity are additional clinical symptoms of envenomation caused by N. oxiana. [32] The untreated mortality rate among those infected by N. oxiana is around 80%, making it the highest among all Naja species. [28] Due to the deadly toxicity of this species' venom, huge amounts of antivenom are required to treat envenomation by this species as opposed to other Asian cobras in the same region, including the Indian cobra (N. naja).

Taxonomy

The genus has a number of species complexes, some of which have only lately been recognized or described, that consist of closely related and frequently similar-appearing species. Recent taxonomic research has identified some species that are not yet listed in ITIS:

Naja anchietae (Bocage, 1879), is regarded by Mertens (1937) and Broadley (1958) as a subspecies of N. haje and N. annulifera, respectively (1995). Broadley and Wüster (2004) consider it to be a complete species.

Arabica Nja The Arabian cobra, Scortecci, 1932, was previously regarded as a subspecies of N. haje but has lately been given the rank of a species.

Ashe's spitting cobra, or Naja ashei Broadley and Wüster, 2007, is a recently described species of snake that can spit a huge amount of poison.

Long thought to be a subspecies of Naja nigricollis Bogert, 1940, it was recently discovered to be a full subspecies (with N. nigricollis woodi as a subspecies). 

A new species, marked by significant senegalensis Trape et al., 2009, has been described that includes what were once thought to be the populations of N. haje found in the West African savanna.

According to Ceraco et al. (2017), Naja peroescobari is a new species that includes what was hitherto thought to be the So Tomé population of N. melanoleuca.

Negative guinea A new species, Broadley et al., 2018, includes what were hitherto thought to be the West African forest populations of N. melanoleuca.

According to Broadley et al. (2018), a new species called Naja savannula now includes what were hitherto thought to be N. naja populations found in the West African savanna.