The desert froglet, chirping froglet, or sparrow froglet (''Crinia deserticola'') is a species of

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

in the family

Myobatrachidae Myobatrachidae, commonly known as Australian ground frogs or Australian water frogs, is a family of frogs found in Australia and New Guinea. Members of this family vary greatly in size, from species less than long, to the second-largest frog in ...

endemic Endemism is the state of a species being found only 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 foun ...

to Australia. Desert froglets occur mainly in dry or moist

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach th ...

habitats, principally from the mid-western border of

Northern Territory The Northern Territory (abbreviated as NT; known formally as the Northern Territory of Australia and informally as the Territory) is an states and territories of Australia, Australian internal territory in the central and central-northern regi ...

, south-east into western

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

and

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

and the north-east corner of

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

. They can also be found along the Queensland coast where it has been recorded between Townsville and Cooktown, and as far south as

Hervey Bay Hervey Bay () is a city on the coast of the Fraser Coast Region of Queensland, Australia. The city is situated approximately or 3½ hours' highway drive north of the state capital, Brisbane. It is located on the bay of the same name open to ...

(300 km north of

Brisbane Brisbane ( ; ) is the List of Australian capital cities, capital and largest city of the States and territories of Australia, state of Queensland and the list of cities in Australia by population, third-most populous city in Australia, with a ...

Taxonomy

General

The desert froglet is a member of the family

. However debate exists about its scientific and common names. For instance, because comparative phylogeny studies of ''

Crinia ''Crinia'' is a genus of frog, native to Australia, and part of the family Myobatrachidae. It consists of small frogs, which are distributed throughout most of Australia, excluding the central arid regions. Many of the species within this genus ...

'' species are not comprehensive, there is debate over the taxonomic accuracy of its species groupings. One exception is the synonymisation of the genus ''Ranidella'' with ''Crinia'' based on morphological data and

serum albumin Serum albumin, often referred to simply as blood albumin, is an albumin (a type of globular protein) found in vertebrate blood. Human serum albumin is encoded by the ''ALB'' gene. Other mammalian forms, such as bovine serum albumin, are chem ...

similarities with ''R.signifera'' and ''C.signifera''. In addition, although the term 'froglet' may seem suited as a general descriptor of smaller species, further taxonomic research of ''Crinia'' species, such as the desert froglet, is needed to clarify the relevancy of this term.

Genetic records

''Crinia deserticola'' isolate SAMAR45118 tRNA-Gln and tRNA-Met genes, complete sequence; and NADH dehydrogenase subunit 2 (ND2) gene, partial cds; mitochondrial
* 650 bp linear DNA * Accession: JX473815.1 GI: 40106496
''Crinia deserticola'' isolate SAMAR52124 tRNA-Gln and tRNA-Met genes, complete sequence; and NADH dehydrogenase subunit 2 (ND2) gene, partial cds; mitochondrial
* 650 bp linear DNA * Accession: JX473814.1 GI: 40106496
''Crinia deserticola'' 658 mitochondrial partial nadh4 gene for NADH dehydrogenase subunit 4
* 408 bp linear DNA * Accession: AJ269697.1 GI: 779938
''Crinia deserticola'' 658 mitochondrial partial 16S rRNA gene
* 468 bp linear DNA * Accession: AJ269696.1 GI: 7799384

Description

The desert froglet is a ground dwelling frog with skin colour, texture and pattern variation common to other ''Crinia'' species. Generally the belly of adults is granular (not blotchy pink like the

Tasmanian froglet The Tasmanian froglet (''Crinia tasmaniensis'') is a species of ground-dwelling frog that occurs only in Tasmania, Australia. Description This is a fairly small species of frog, up to about 30 mm. It is variable, but is generally brown (d ...

). The male belly is uniformly white or grey in colour, and possibly flecked grey, whereas the female belly is either white, speckled, or boldly blotched with black or grey. The throat of adults lack a median white line, unlike the Wallum froglet; with throats of breeding males white or grey and the chin completely dark. Spots are either inconspicuous or absent on the chest of both genders. Also, adults have distinct

dermal The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided i ...

fringes on their toes and the hind side of their thighs lack the pink or red coloration of the

quacking frog The quacking frog (''Crinia georgiana''), also known as the red-thighed froglet due to its legs tending to be bright red, is a species of frog from the Myobatrachidae family and is in a clad with five other species. The frog is well known for ...

. The tympanum is obscure but not hidden unlike the remote froglet. The length of the adult snout-vent is usually less than 18 mm, which is shorter than the eastern sign-bearing froglet, and is a pale brown colour or slightly patterned. Additional diagnostic descriptors include: bluntly rounded snout, evenly rounded

canthus rostralis In snakes and amphibians, the canthus, canthal ridge or ''canthus rostralis''Spawls S, Branch B. 1995. ''The Dangerous Snakes of Africa''. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. . is the angle between the flat crown of the head and the ...

, outwardly sloping loreal region, bluntly pointed head (dorsal view), lacks supratympanic fold, elongated tongue, lacks vomerine teeth, toothed upper jaw,

vocal sac The vocal sac is the flexible Biological membrane, membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the voca ...

with slit-like openings on the floor of the mouth. The distal segment of fingers is blunt, not expanded, with roundish sub-articular tubercles (one on 1st and 2nd fingers; two on 3rd and 4th fingers), supernumerary tubercles are present on each palm, two metacarpal tubercles are present, webbing is absent as is the nuptial pad, and subcutaneous glands are present on the base of the 1st finger. Hind limbs are robust with blunt digital segmentation of toes with broad fringes and rounded metatarsal tubercles, supernumerary tubercles are absent indicating the desert froglet does not burrow. Males mature at about 13.0–18.0 cm in length whereas females grow slightly larger to 13.0–18.0 cm..

Distribution and habitat

Distribution map
Desert froglets are found in arid regions, especially in areas of black soil, extending across the Australian continent from the Kimberley region to the north-west of New South Wales and much of Queensland. The species is often associated with static, temporary or permanent water bodies where it shelters under leaves. They have also been located within artificial habitats such as farm dams, and sheltering under corrugated iron and timber piles.

Reproduction

Mating call

The desert froglet is recognised by the 'melodious chirping
call
of the adult male, which sounds similar to a

house sparrow The house sparrow (''Passer domesticus'') is a bird of the Old World sparrow, sparrow family Passeridae, found in most parts of the world. It is a small bird that has a typical length of and a mass of . Females and young birds are coloured pa ...

. Each call consists of a repeating pattern: two pulses of 60 milliseconds each and 4000

hertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in ter ...

, which is immediately followed by two additional double pulses of decreasing energy and quickening rate, and a brief pause. Calls are distinct from the shorter creaking call of

Sloane's froglet Sloane's froglet (''Crinia sloanei'') is a species of frog in the family Myobatrachidae. It is endemic to Australia. Its natural habitats are subtropical or tropical seasonally wet or flooded lowland grassland and intermittent freshwater marshe ...

, stretched out call of the eastern sign-bearing froglet, lower pitch of the Wallum froglet, and grating sounds of the common eastern froglet. Calling males can be found either hiding under vegetation or exposed at water edges.

Life history

Spawns of small eggs are laid as submerged clumps either directly within the water or attached to submerged vegetation. Eggs are black at the animal pole and cream at the vegetal.

Tadpole A tadpole or polliwog (also spelled pollywog) is the Larva, larval stage in the biological life cycle of an amphibian. Most tadpoles are fully Aquatic animal, aquatic, though some species of amphibians have tadpoles that are terrestrial animal, ...

appearance is the same as the Eastern sign-bearing froglet and Common eastern froglet: dark brown in colour, a

dextral Sinistral and dextral, in some scientific fields, are the two types of chirality ("handedness") or relative direction. The terms are derived from the Latin words for "left" (''sinister'') and "right" (''dexter''). Other disciplines use different ...

anal opening,

sinistral Sinistral and dextral, in some scientific fields, are the two types of chirality ("handedness") or relative direction. The terms are derived from the Latin words for "left" (''sinister'') and "right" (''dexter''). Other disciplines use different ...

spiracle, blunt tail, labial papillar row interrupted on anterior and posterior portions, and a labial tooth row pattern of I, 1/1, II.

Threats

Although the desert froglet is not considered to be at threat of extinction, alterations to inland waters have potential to impact their populations, especially when water bodies are isolated and individuals cannot disperse to additional sources. Under these circumstances, any activity that negatively impacts these water bodies may cause species decline, including drinking, fouling and grazing by livestock and feral animals, road construction, non-native plants, groundwater extraction, pollution, tourism, mining, and long-term changes in weather patterns.