Pseudonaja Mengdeni
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The western brown snake (''Pseudonaja mengdeni'') is commonly known as Mengden's brown snake, and alternatively, gwardar. ''Pseudnaja mengdeni'' is
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
to Australia. It is highly variable in colour and patterns and is a highly dangerous
elapid Elapidae (, commonly known as elapids ; grc, ἔλλοψ ''éllops'' "sea-fish") is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydoce ...
whose bite can cause severe symptoms resulting in death. It is one of the three species originally classified as '' Pseudonaja nuchalis'' along with '' P. aspidorhyncha'', and ''P. nuchalis''.


Taxonomy

Previously the western brown snake was considered a ' morph' form of ''Pseudonaja nuchalis'', recent genetic studies have proven it to be genetically unique. It is estimated that ''Pseudonaja nuchalis'' could include in excess of 10 different
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
. Although currently there have been 8 species
chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
ally identified species these include: ''P. aspidorhyncha'', ''P. mengdeni'', ''P. imperator'', ''P. acutirostris'', ''P. gowi'', ''P. carinata'', ''P. kellyi'' and ''P. nuchalis''.


Description

''Pseudonaja mengdeni'' grows up to a total length of 2m with an average length 1.2m It has slender body and narrow head. Mengden's brown snake is highly variable in colour and patterns, ranging from light brown to almost black. However it has two distinct forms ‘Orange with black head’ or ‘Pale head, grey nape’ The underside along the belly is often cream, yellow, orange, or grey in colouration, frequently consisting of dark orange or grey blotches.
Scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number w ...
on the head often form a black V or W pattern. Western brown snakes can be confused with the
Eastern brown snake The eastern brown snake (''Pseudonaja textilis''), often referred to as the common brown snake, is a species of highly venomous snake in the family Elapidae. The species is native to eastern and central Australia and southern New Guinea. It was ...
which has a pink mouth lining, the Northern brown snake has a purplish/blue-black mouth lining. P. mengdeni has a distinctive large strap-like scale around the front of the snout. To accurately identify this species the scales around the mid-body and along the lips need to be counted. 180-230
ventral scales In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...
, 45-70
subcaudals In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...
with a divided
anal scale Anal may refer to: Related to the anus *Related to the anus of animals: ** Anal fin, in fish anatomy ** Anal vein, in insect anatomy ** Anal scale, in reptile anatomy *Related to the human anus: ** Anal sex, a type of sexual activity involv ...
and 17 or 19 rows of smooth mid-body scales. However this must only be done by an experienced
herpetologist Herpetology (from Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is the branch of zoology concerned with the study of amphibians (including frogs, toads, salamanders, newts, and caecilians ( gymnophiona)) and rep ...
, as a scratch from the fangs can still be fatal from ''P. mengdeni''. Confusion between the species is largely due to the possible hybridisation between the ''Pseudonaja'' species. The western brown snake is often confused with other ''Pseudonaja'' spp. (brown snakes) and also '' Aspidites melanocephalus'' ( black headed python).


Distribution and habitat

Found from the coast of
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
through central Australia to the north-west of
New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...
and western
Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , establishe ...
. The species distribution is poorly defined within its northern limits however it is absent from wetter areas of eastern Australia and south-western Western Australia. ''Pseudonaja mengdeni'' is practically found throughout all dry to arid areas including, woodlands, Boree woodlands, sandhill woodlands, mallee woodlands, spinifex deserts, spinifex-covered dunefields, sandplains, stony plains,
croplands A farm (also called an agricultural holding) is an area of land that is devoted primarily to agricultural processes with the primary objective of producing food and other crops; it is the basic facility in food production. The name is used f ...
, grasslands and
temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...
sclerophyll Sclerophyll is a type of vegetation that is adapted to long periods of dryness and heat. The plants feature hard leaves, short internodes (the distance between leaves along the stem) and leaf orientation which is parallel or oblique to direct ...
forests A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
. The Western brown snake often found within fallen timber, dead trees, shrubs, native grasses and ground cavities.


Diet

''Pseudonaja mengdeni'' preys upon small reptiles,
mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...
, other snakes, ground nesting birds and
bird egg Bird eggs are laid by the females and range in quantity from one (as in condors) to up to seventeen (the grey partridge). Clutch size may vary latitudinally within a species. Some birds lay eggs even when the eggs have not been fertilized; it ...
s.


Reproduction

''Pseudonaja mengdeni'' is oviparous and can lay up to in excess of 12 eggs per clutch.


Venom

''Pseudonaja mengdeni'' has highly dangerous
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 st ...
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 – specificall ...
and haemotoxic and can cause severe symptoms resulting in death. Mengden's brown snake is considered dangerously venomous.
Antivenom 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 th ...
used in case of envenoming is the brown snake Antivenom If bitten first aid must be applied and medical attention sought.


Behaviour

''Pseudonaja mengdeni'' will rear their fore-body into an S-shape when threatened lifting their head off the ground and open their mouth. Is also a
terrestrial Terrestrial refers to things related to land or the planet Earth. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
species that is diurnal however it can be active on warm nights


References

{{Taxonbar, from=Q3409783 mengdeni Snakes of Australia Reptiles described in 1985