Tusked frog

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Tusked frog
Adelotus brevis.jpg
Male
Adelotus brevis female.jpg
Female
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Limnodynastidae
Genus: Adelotus
Ogilby, 1907
Species:
A. brevis
Binomial name
Adelotus brevis
(Günther, 1863)
Adelotus brevis distribution map.png
Range of the tusked frog

The tusked frog (Adelotus brevis) is a species of ground-dwelling frog native to eastern Australia from Eungella National Park, Queensland south to Ourimbah, New South Wales. It is the only species in the genus Adelotus - adelotus meaning "unseen" and brevis meaning "short". [1]

Contents

Description

The tusked frog is a unique frog within Australia, as it is the only species where the female is smaller than male. Males can reach a maximum length of about 5 centimetres (2.0 in), while females reach 4 centimetres (1.6 in). The common name of "tusked frog" derives from the small protrusions on the lower jaw, similar in position to tusks, which can reach about 5 millimetres (0.20 in) in length in males (only visible when the mouth is open).

The pair of bony tusks are modified teeth that protrude from the middle of the lower jaw and fit into special grooves on the upper jaw when the mouth is closed. They are slightly curved and sharply pointed, and are present in both males and females, although they are larger in males. [2]

Males have been observed 'locking jaws' with each other, in a similar way to male deer locking antlers in the struggle to exert dominance over each other. [2] Male tusked frogs have a disproportionally large-sized head, compared to the body, and females have a smaller proportioned sized head than males. The males have been known to fight, biting each other under the head, and around the neck. This behaviour has presumably led to the sexual dimorphism of larger heads, body size and tusks to increase success of fights (Katsirakos & Shine 1997).

The dorsal surface of the frog is normally brown, but can be olive to black, with low ridges, warts and irregular darker markings. There is usually a butterfly shaped marking between the eyes. [1] The [ventral] surface of this species is more striking - being marbled black and white with flashes of red on the groin and hind legs. Males and females have different belly patterns. Fingers and toes are cylindrical and are not webbed. [2]

Ecology and behaviour

A. brevis is associated with dams, ditches, flooded grassland and creeks in rainforest, wet sclerophyll forest and woodland. It is known from coastal and highland areas, however it has suffered declines in many highland areas, particularly the New England Tablelands of New South Wales.

Males create hidden nest sites in leaf litter and vegetation in streams and the edges of dams. This species has a call like "tok-tok", males call from the nest site and can be difficult to find. Breeding takes place in spring and summer and eggs are laid as a foamy mass in the nest, hidden from sunlight. The eggs are white in colour and lack pigment.

In the breeding season (October - December), males build nests out of foam hidden from direct sunlight in ponds and swamps. Over 600 eggs may be laid in each floating mass of foam, and are guarded by the male until they hatch into tadpoles. The tadpoles grow over a period of two to three months to around 3 to 3.5 cm, when they undergo metamorphosis into 'mini adult' froglets. [2]

Conservation status and threats

The IUCN has listed the tusked frog in the near threatened category of the Red List of Threatened Species, and notes that it is probably in significant decline due to chytridiomycosis. [2]

The Southern Tablelands population has been listed as an endangered population under the Threatened Species Conservation Act, following the disappearance of the species from the rest of its former Tablelands range. [2]

Urban and agricultural development are thought to be the primary threats to this species, causing the degradation and loss of its habitat. Introduced species are causing further decline, such as the predatory eastern mosquitofish (Gambusia holbrooki), and weed species which outcompete the tusked frog's natural vegetation. [2]

Related Research Articles

A tadpole is the larval stage in the life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some features that may not be found in adult amphibians such as a lateral line, gills, and tails. As they undergo metamorphosis, the diet of tadpoles changes and they will start to breathe air.

Corroboree frog Name for two species of amphibian

Corroboree frogs comprise two species of frog native to the Southern Tablelands of Australia. Both species are small, poisonous ground-dwelling frogs. The two species are the southern corroboree frog and the northern corroboree frog. They are unique among frogs in that they produce their own poison rather than obtain it from their food source as is the case in every other poisonous frog species.

Green and golden bell frog Species of amphibian

The green and golden bell frog, also named the green bell frog, green and golden swamp frog and green frog, is a ground-dwelling tree frog native to eastern Australia. Despite its classification and climbing abilities, it does not live in trees and spends almost all of its time close to ground level. It can reach up to 11 cm (4.5 in) in length, making it one of Australia's largest frogs.

Common eastern froglet Species of amphibian

The common eastern froglet is a very common, Australian ground-dwelling frog, of the family Myobatrachidae.

Spotted grass frog Species of amphibian

The spotted grass frog or spotted marsh frog is a terrestrial frog native to Australia. It is distributed throughout all of New South Wales and Victoria, eastern South Australia, the majority of Queensland, and eastern Tasmania. It is also naturalised in Western Australia, having been unintentionally introduced at Kununurra in the 1970s, apparently during the relocation of several hundred transportable homes from Adelaide.

Striped marsh frog Species of amphibian

The striped marsh frog or brown-striped frog is a predominantly aquatic frog native to coastal Eastern Australia. It is a common species in urban habitats.

Gastric-brooding frog Extinct genus of amphibians

The gastric-brooding frogs or platypus frogs (Rheobatrachus) is a genus of extinct ground-dwelling frogs native to Queensland in eastern Australia. The genus consisted of only two species, both of which became extinct in the mid-1980s. The genus is unique because it contains the only two known frog species that incubated the prejuvenile stages of their offspring in the stomach of the mother.

Red-crowned toadlet Species of amphibian

The red-crowned toadlet is a species of Australian ground frog, restricted to the Sydney Basin, New South Wales. It is only found around sandstone escarpment areas around Sydney, from Ourimbah in the north, Nowra to the south and the Blue Mountains areas to the west.

Bibrons toadlet Species of amphibian

The Bibron's toadlet or brown toadlet is a species of Australian ground-dwelling frog that, although having declined over much of its range, is widespread through most of New South Wales, Victoria, south-eastern Queensland and eastern South Australia, including Kangaroo Island.

Red-backed toadlet Species of amphibian

The Red-backed Toadlet is a species of ground frog native to the coast and adjacent ranges of eastern Australia, from just north of Sydney to South-eastern Queensland.

Wallum froglet Species of amphibian

The wallum froglet is a species of ground-dwelling frog native to the east coast of Australia, from southeast Queensland to Kurnell, NSW. It is strongly associated with Wallum swampland.

Myobatrachidae Family of amphibians

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 1.5 cm (0.59 in) long, to the second-largest frog in Australia, the giant barred frog, at 12 cm (4.7 in) in length. The entire family is either terrestrial or aquatic frogs, with no arboreal species.

Fleays barred frog Species of amphibian

Fleay's barred frog is a large species of frog restricted to small pockets of rainforest in northern New South Wales and south-eastern Queensland, Australia.

Booroolong frog Species of amphibian

The Booroolong frog is a species of stream-dwelling frog native to the Great Dividing Range in New South Wales.

Moaning frog Species of amphibian

The moaning frog is a burrowing frog native to south-western Western Australia.

Marbled frog Species of amphibian

The marbled frog or marbled marsh frog is a species of ground-dwelling frog native to northern and north-eastern Australia, and southern New Guinea in both Indonesia and Papua New Guinea.

Smoky jungle frog Species of amphibian

The smoky jungle frog is a species of frog in the family Leptodactylidae. It is found in Bolivia, Brazil, Colombia, Ecuador, Costa Rica, Panama, French Guiana, and Peru. Its natural habitats are tropical and subtropical moist broadleaf forests, subtropical or tropical swamps, subtropical or tropical moist montane forest, rivers, freshwater marshes, intermittent freshwater marshes, and aquaculture ponds.

<i>Physalaemus ephippifer</i> Species of frog

Physalaemus ephippifer is a species of frog in the family Leptodactylidae. It is found in central and eastern Brazilian Amazonia, the Guianas, and southern Venezuela. It might not occur in French Guiana.

Túngara frog Species of amphibian

The túngara frog is a species of frog in the family Leptodactylidae.

<i>Nannophrys ceylonensis</i> Species of amphibian

Nannophrys ceylonensis, commonly known as the Sri Lanka rock frog or the Ceylon streamlined frog, is a species of frog. It used to be placed in the large frog family Ranidae but a phylogenetic study was undertaken using DNA sequences and it is now included in the family Dicroglossidae. It is endemic to Sri Lanka where its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, rivers and streams.

References

  1. 1 2 Martyn Robinson (2005) A Field Guide to the Frogs of Australia. Australian Museum and Reed New Holland Publication. ISBN   1876334835
  2. 1 2 3 4 5 6 7 "Tusked frog (Adelotus brevis)". EDGE of Existence programme (Evolutionarily Distinct and Globally Endangered species). Zoological Society of London. Retrieved 18 April 2014.