Asp Viper

Appearance

The species grows to an average total length of 60–65 centimetres. Males reach a maximum total length of 85 cm, females rarely more than 75 cm. Males, however, are a little slimmer than females. The tail is very short: one-seventh to one-ninth of total body length in females, and one-sixth to one-eighth in males.

The head is broad, triangular and quite distinct from the neck. The tip of the snout is slightly but distinctly upturned. The rostral scale is generally higher than it is wide, touching 2 to 3 scales on the upper side of the snout. Dorsally, the snout is flat with distinct and slightly raised sharp margins. The nasal scale is single and separated from the rostral by a single nasorostral scale. The crown is covered with numerous small and irregular scales of different sizes that are mostly smooth, but sometimes slightly keeled. Frontal and parietal scales are usually not present, but if so, they are small and irregularly shaped, with the frontal separated from the supraoculars by 2 scale rows. The supraocular scales are large and distinct, separated by 4–7 scale rows. There are 10–12 small circumorbital scales below the supraocular. The eye is separated from the supralabials by 2 scale rows. The vertical diameter of the eye is about the same as the distance between the eye and the mouth. There are 9–13 supralabials. The 4th–5th supralabials are separated from the eye by 2 rows of small scales, but sometimes there is a single scale between the 4th supralabial and the eye. Generally, the temporal scales are smooth, but sometimes slightly keeled.

Midbody, there are 21–23 rows of dorsal scales. These are strongly keeled, except for the outermost rows that vary and are sometimes smooth. There are 134–170 ventral scales. Subspecies "V. a. aspis" averages fewer than 150 ventrals, while "V. a. atra" averages more. The anal scale is single. Males have 32–49 subcaudals, females 30–43. The subcaudal scales are paired.

The dorsal markings vary strongly, but only rarely take the form of a clear zigzag, as in "V. berus".

Naming

Common names of "Vipera aspis" include "asp", "asp viper", "European asp", "aspic viper", "European viper" and "Jura viper".

Status

This species is classified as Least Concern according to the IUCN Red List of Threatened Species. So listed due to its wide distribution, tolerance of a broad range of habitats, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

However, subspecies "V. a. aspis" is categorized as Critically Endangered in Switzerland, "V. a. atra" is categorized as Vulnerable, and "V. a. francisciredi" is categorized as Endangered.

In general, the species is also listed as protected under the Berne Convention.

Habitat

This species has a few clearly defined and relatively specific habitat requirements. It needs warm areas that are exposed to the sun, structured vegetation and comparatively dry soils. In Italy and France, it is often found in areas with low mountains or hills, notably in limestone regions, but sometimes occurs in lower plains. It has a preference for vegetated areas or environments with at least some cover. Here it can be found on sunny slopes, on scrublands, in glades, in mountain meadows, forest clearings, at the borders of woods, in rubbish dumps and in stone quarries. In Italy, it occurs in mesic chestnut/oak woodlands and often near streams. Although it is not strongly associated with high altitudes, it has been found at well over 2,100 m above sea level in the Pyrenees.

Defense

A bite from this species can be more severe than from "V. berus" and is very painful. According to Stemmler, about 4% of all untreated bites are fatal. Lombardi and Bianco mention that this species is responsible for 90% of all cases of snakebite in Italy and it is the only mortal snake in Italian mountains.

The toxicity of the venom varies. Stemmler states that the population in Passwang district, Switzerland have the strongest venom based on studies conducted on mice. Compared to venoms from other species, it is relatively toxic. Brown gives LD50 values of 1.0 mg/kg IV and 1.0–2.0 mg/kg SC. Tu "et al." report 4.7 mg/kg IM. Venom yield is relatively low. Boquet reported a daily extraction figure of 9–10 mg....hieroglyph snipped...

Envenomation symptoms include rapidly spreading acute pain, followed by edema and discoloration. Severe haemorrhagic necrosis may occur within a few hours. Vision may be severely impaired, most likely due to degradation of blood and blood vessels in the eyes. The venom has both coagulant and anticoagulant effects. The venom may also affect glomerular structure, which can lead to death due to renal failure.

According to Cheymol "et al.", the venom does not affect neuromuscular contractions in "in vitro" preparations."Echis carinatus" " |trans_title=Comparison of the principal pharmacologic properties of different venoms of "Echis carinatus" |journal=Archives Internationales de Pharmacodynamie et de Therapie |volume=205 |issue=2 |pages=293–304}} Lack of this neurotoxic affect would indicate that fatal cases involving the cardiovascular system are the result of direct muscle injury or reduced oxygen exchange. On the other hand, Gonzalez reported that in two cases the victims developed neurotoxic symptoms, including difficulty in breathing and swallowing, as well as paralysis of the bitten limbs.