Field's horned viper Mallow D, Ludwig D, Nilson G (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company, Malabar, Florida. 359 pp. . (''Pseudocerastes fieldi)'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Viperidae Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous snake, venomous and have long (relat ...

. The species is native to the deserts of the

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

. Like all other vipers, it is

venomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

. It was previously considered a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of the Persian horned viper (''Pseudocerastes persicus''). The main differences between this species and the Persian horned viper are in scalation and venom composition.

Taxonomy and etymology

Formerly considered a subspecies of ''P. persicus'', most sources elevate ''P. fieldi'' to species level. The first phylogenetic study of the genus '' Pseudocerastes'', published by Fathinia et al. in 2014, shows that ''P. fieldi'' has equal genetic distance from both ''P. persicus'' and another species of the same genus, '' P. urarachnoides''. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''fieldi'' is in honor of

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...

anthropologist An anthropologist is a scientist engaged in the practice of anthropology. Anthropologists study aspects of humans within past and present societies. Social anthropology, cultural anthropology and philosophical anthropology study the norms, values ...

Henry Field, who collected the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

. The

Field Museum of Natural History The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educationa ...

Chicago Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...

and its scientific publication, ''Fieldiana'', in which K.P. Schmidt's original description of this viper appeared, are named for Henry Field's grandfather,

Marshall Field Marshall Field (August 18, 1834January 16, 1906) was an American entrepreneur and the founder of Marshall Field's, Marshall Field and Company, the Chicago-based department stores. His business was renowned for its then-exceptional level of qua ...

. Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (''Pseudocerastes fieldi'', p. 89).

Description

Outwardly, Field's horned viper differs from the Persian horned viper (''Pseudocerastes persicus'') in certain (lower) scale counts: Spawls S, Branch B (1995). ''The Dangerous Snakes of Africa''. Dubai: Ralph Curtis Books. Oriental Press. 192 pp. .
Additional differences from the Persian horned viper include much shorter (relatively to the overall body length) tail as well as the fact that while in ''P. persicus'' all dorsal and lateral scales are strongly keeled, ''P. fieldi'' has several rows of almost smooth lateral scales.

Geographic distribution

According to McDiarmid et al. (1999) ''P. fieldi'' is found in the

Sinai Peninsula The Sinai Peninsula, or simply Sinai ( ; ; ; ), is a peninsula in Egypt, and the only part of the country located in Asia. It is between the Mediterranean Sea to the north and the Red Sea to the south, and is a land bridge between Asia and Afri ...

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

Jordan Jordan, officially the Hashemite Kingdom of Jordan, is a country in the Southern Levant region of West Asia. Jordan is bordered by Syria to the north, Iraq to the east, Saudi Arabia to the south, and Israel and the occupied Palestinian ter ...

, northern

Saudi Arabia Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in West Asia. Located in the centre of the Middle East, it covers the bulk of the Arabian Peninsula and has a land area of about , making it the List of Asian countries ...

, northwestern

Iraq Iraq, officially the Republic of Iraq, is a country in West Asia. It is bordered by Saudi Arabia to Iraq–Saudi Arabia border, the south, Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq border, the east, the Persian Gulf and ...

, and possibly in southern

Syria Syria, officially the Syrian Arab Republic, is a country in West Asia located in the Eastern Mediterranean and the Levant. It borders the Mediterranean Sea to the west, Turkey to Syria–Turkey border, the north, Iraq to Iraq–Syria border, t ...

. The type locality given in the original description is "Bair Wells, Transjordania" ordan According to Mallow et al. (2003) it is found in the Sinai Peninsula, southern Israel, Jordan, extreme northern Saudi Arabia, and southwestern Iraq.

Habitat

The preferred natural

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s of ''P. fieldi'' are

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

and

shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, herbaceous plant, herbs, and geophytes. Shrubland may either occur naturally o ...

, at altitudes up to . It has also been found in agricultural areas, but not in or around houses.

Reproduction

''P. fieldi'' is

oviparous Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs known as eggs, which nurture the embryo into moving offsprings kno ...

Venom

There is a more pronounced difference between the two species, ''P. fieldi'' and ''P. persicus'', with regard to their

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

. While Persian horned viper venom exhibits strong

hemorrhagic Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, va ...

activity typical of most

vipers Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous and have long (relative to non-viper ...

, the venom of ''P. fieldi'' is unusual in that it contains several fractions that show marked

neurotoxic Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifical ...

activity. No

antivenin Antivenom, also known as antivenin, venom antiserum, and antivenom immunoglobulin, is a specific treatment for envenomation. It is composed of antibodies and used to treat certain venomous bites and stings. Antivenoms are recommended only if t ...

is available for

bites Biting is an action involving a set of teeth closing down on an object. It is a common zoological behavior, being found in toothed animals such as mammals, reptiles, amphibians, fishes, and arthropods. Biting is also an action humans participate ...

from either species. It is reported that a polyvalent antiserum does offer some protection from the hemotoxins, but none against the neurotoxic effects of ''P. fieldi'' venom.