Long-tailed Planigale
Encyclopedia
The Long-tailed Planigale (Planigale ingrami), also known as Ingram's Planigale or the Northern Planigale, is the smallest of all marsupial
s, and one of the smallest of all mammal
s. It is rarely seen but a quite common inhabitant of the blacksoil plains, clay-soiled woodlands, and seasonally flooded grasslands of Australia
's Top End
.
, who placed it in the genus Phascogale
. The species was moved in 1928 by Ellis Le Geyt Troughton
, who created the genus Planigale
for it and the other then-known species, the Common Planigale (P. maculata), and described the Narrow-nosed Planigale
(P. tenuirostris). The species has since suffered some taxonomic
confusion, having been referred to as Planigale subtilissima; there has also been some confusion concerning subspecies. Currently, three subspecies are recognised:
s have a flattened head, much broader than it is deep. This smallest planigale takes that trend to an extreme: at just 3 to 4 mm (0.118110236220472 to 0.15748031496063 in) from top to bottom, the skull is one-fifth as deep as it is wide. The purpose, it seems, is to allow it to squeeze into the tiniest of soil cracks; to find its prey, perhaps to avoid predators, or more probably for both reasons. The clays and blacksoils of the Top End typically develop deep cracks as they dry after the monsoonal summer rains, which persist right through the eight-month dry season until the wet begins again, usually producing floods that force small creatures like the Long-tailed Planigale to seek refuge on high ground.
The head shape aside (which in any case is not obvious from all angles), the Long-tailed Planigale looks rather like a very small mouse
with a long, bare tail. The muzzle is pointed, the fur a nondescript and variable brown, the hindlegs a little bigger than the forelegs, allowing it to stand semi-crouched on hindlegs and tail, rather like a tiny squirrel
.
Combined head-body length varies from 55 to 65 mm, averaging 59 mm in both sexes, the tail length is similar. Average male weight is 4.2 grams, 4.3 grams for females; a really large specimen can reach almost 6 grams.
, it is carnivorous, living on invertebrate
s and small vertebrate
s which they catch by energetic nocturnal hunting through leaf litter and in soil cracks.
By night it is an active and fearless hunter, preying mostly on insect
s and their larva
e, small lizard
s, and young mammal
s almost as large as itself. With the larger prey like grasshopper
s, an initial pounce is often insufficient and the planigale bites repeatedly until its prey no longer struggles. Usually, it eats only the soft parts, discarding the head and wings.
from the Pilbara
through the Great Sandy Desert
and the Kimberley region
in Western Australia
to the Barkly Tableland in the Northern Territory
and Townsville in Queensland
.
Marsupial
Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
s, and one of the smallest of all mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. It is rarely seen but a quite common inhabitant of the blacksoil plains, clay-soiled woodlands, and seasonally flooded grasslands of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
's Top End
Top End
The Top End of northern Australia is the second northernmost point on the continent. It covers a rather vaguely-defined area of perhaps 400,000 square kilometres behind the northern coast from the Northern Territory capital of Darwin across to Arnhem Land with the Indian Ocean on the west, the...
.
Taxonomy
The Long-tailed Planigale was described in 1906 by Oldfield ThomasOldfield Thomas
Oldfield Thomas FRS was a British zoologist.Thomas worked at the Natural History Museum on mammals, describing about 2,000 new species and sub-species for the first time. He was appointed to the Museum Secretary's office in 1876, transferring to the Zoological Department in 1878...
, who placed it in the genus Phascogale
Phascogale
The Phascogales , also known as Wambengers, are carnivorous Australian marsupials of the family Dasyuridae. There are two species: the Brush-tailed Phascogale and the Red-tailed Phascogale...
. The species was moved in 1928 by Ellis Le Geyt Troughton
Ellis Le Geyt Troughton
Ellis Le Geyt Troughton was an Australian zoologist and mammalogist. He wrote Furred Animals of Australia in 1941. He was the first Honorary Life Member of The "Australian Mammal Society's" and The Ellis Troughton Memorial Award is named for him.- References :...
, who created the genus Planigale
Planigale
The genus Planigale are small carnivorous marsupials found in Australia and New Guinea. It is the only genus in the Planigalini tribe of the subfamily Sminthopsinae...
for it and the other then-known species, the Common Planigale (P. maculata), and described the Narrow-nosed Planigale
Narrow-nosed Planigale
The Narrow-nosed Planigale is a species of very small marsupial carnivore of the family Dasyuridae.-Taxonomy:The Narrow-nosed Planigale was described by Ellis Le Geyt Troughton in 1928, separating it from the Common Planigale with which it had previously been associated...
(P. tenuirostris). The species has since suffered some taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
confusion, having been referred to as Planigale subtilissima; there has also been some confusion concerning subspecies. Currently, three subspecies are recognised:
- P. i. ingrami, found in the Northern TerritoryNorthern TerritoryThe Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
to Townsville, QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
; - P. i. brunnea, found in the RichmondRichmond, QueenslandRichmond is a town in western Queensland, Australia. The town is located on the Flinders Highway, 498 km west of Townsville and 406 km east of Mount Isa. It is the administrative centre of the Richmond Shire. At the 2006 census, Richmond had a population of 554.The Flinders River forms...
area of QueenslandQueenslandQueensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
; - P. i. subtilissima, found in the Ord Victoria PlainOrd Victoria PlainOrd Victoria Plain is an Interim Biogeographic Regionalisation for Australia region in Western Australia. and Northern Territory.-Location and description:...
and the Kimberley region of Western AustraliaKimberley region of Western AustraliaThe Kimberley is one of the nine regions of Western Australia. It is located in the northern part of Western Australia, bordered on the west by the Indian Ocean, on the north by the Timor Sea, on the south by the Great Sandy and Tanami Deserts, and on the east by the Northern Territory.The region...
.
Description
The Long-tailed Planigale has an extraordinary head shape. All planigalePlanigale
The genus Planigale are small carnivorous marsupials found in Australia and New Guinea. It is the only genus in the Planigalini tribe of the subfamily Sminthopsinae...
s have a flattened head, much broader than it is deep. This smallest planigale takes that trend to an extreme: at just 3 to 4 mm (0.118110236220472 to 0.15748031496063 in) from top to bottom, the skull is one-fifth as deep as it is wide. The purpose, it seems, is to allow it to squeeze into the tiniest of soil cracks; to find its prey, perhaps to avoid predators, or more probably for both reasons. The clays and blacksoils of the Top End typically develop deep cracks as they dry after the monsoonal summer rains, which persist right through the eight-month dry season until the wet begins again, usually producing floods that force small creatures like the Long-tailed Planigale to seek refuge on high ground.
The head shape aside (which in any case is not obvious from all angles), the Long-tailed Planigale looks rather like a very small mouse
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...
with a long, bare tail. The muzzle is pointed, the fur a nondescript and variable brown, the hindlegs a little bigger than the forelegs, allowing it to stand semi-crouched on hindlegs and tail, rather like a tiny squirrel
Squirrel
Squirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots , flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia...
.
Combined head-body length varies from 55 to 65 mm, averaging 59 mm in both sexes, the tail length is similar. Average male weight is 4.2 grams, 4.3 grams for females; a really large specimen can reach almost 6 grams.
Diet
Like all members of the DasyuromorphiaDasyuromorphia
The order Dasyuromorphia comprises most of the Australian carnivorous marsupials, including quolls, dunnarts, the numbat, the Tasmanian devil, and the recently extinct thylacine...
, it is carnivorous, living on invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s and small vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
s which they catch by energetic nocturnal hunting through leaf litter and in soil cracks.
By night it is an active and fearless hunter, preying mostly on insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s and their larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e, small lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s, and young mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s almost as large as itself. With the larger prey like grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s, an initial pounce is often insufficient and the planigale bites repeatedly until its prey no longer struggles. Usually, it eats only the soft parts, discarding the head and wings.
Reproduction
Breeding can take place at any time of year, but mostly during the wet season. Four to eight young are born, sometimes as many as 12 in southern populations; the young spend six weeks in the backward-facing pouch, and then about as long again hidden in a grassy nest under bark or other vegetation while the mother forages each night.Distribution and habitat
The Long-tailed Planigale prefers floodplains and savannah woodlands with cracked clay soils, as well as riparian areas and blacksoil plains. It is found across northern AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
from the Pilbara
Pilbara region of Western Australia
The Pilbara is a large, dry, thinly populated region in the north of Western Australia known for its vast mineral deposits, in particular iron ore...
through the Great Sandy Desert
Great Sandy Desert
The Great Sandy Desert is a desert located in the North West of Western Australia straddling the Pilbara and southern Kimberley regions. It is the second largest desert in Australia after the Great Victoria Desert and encompasses an area of...
and the Kimberley region
Kimberley region of Western Australia
The Kimberley is one of the nine regions of Western Australia. It is located in the northern part of Western Australia, bordered on the west by the Indian Ocean, on the north by the Timor Sea, on the south by the Great Sandy and Tanami Deserts, and on the east by the Northern Territory.The region...
in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
to the Barkly Tableland in the Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
and Townsville in Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
.