The azure-thighed tree frog (''Litoria azuroscelis''), azure-thighed treefrog or, in

Indonesian Indonesian is anything of, from, or related to Indonesia, an archipelagic country in Southeast Asia. It may refer to: * Indonesians, citizens of Indonesia ** Native Indonesians, diverse groups of local inhabitants of the archipelago ** Indonesian ...

, ''katak-pohon paha-biru'', is a species of tree frog in the subfamily

Pelodryadinae Pelodryadinae, also known as Australian treefrogs (although not all members are arboreal), is a subfamily of frogs found in the region of Australia and New Guinea, and have also been introduced to New Caledonia New Caledonia ( ; ) is a g ...

of the family

Hylidae Hylidae is a wide-ranging family of frogs commonly referred to as " tree frogs and their allies". However, the hylids include a diversity of frog species, many of which do not live in trees, but are terrestrial or semiaquatic. Taxonomy and ...

that is

native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...

Western New Guinea Western New Guinea, also known as Papua, Indonesian New Guinea, and Indonesian Papua, is the western half of the island of New Guinea, formerly Dutch and granted to Indonesia in 1962. Given the island is alternatively named Papua, the region ...

. It was described by a group of Australian

herpetologists Herpetology (from Ancient Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is a branch of zoology concerned with the study of amphibians (including frogs, salamanders, and caecilians (Gymnophiona)) and reptiles (incl ...

in 2023.

Description

The frog was named for the purple-blue colouration on the hidden portion of its hindlegs. The species is mostly dark green, with reddish-brown irises, and a mostly clear

nictitating membrane The nictitating membrane (from Latin '' nictare'', to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye from the medial canthus to protect and moisten it while maintaining vision. Most ...

, besides the darker dorsal margin. Adult males reach an estimated size of or under 66.6 mm (2.62 in). It differs from other members of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

by the extent of hand webbing, as well as the size, shape, and colouration of the male's

nuptial pad A nuptial pad (also known as thumb pad, or nuptial excrescence) is a secondary sex characteristic present on some mature male frogs and salamanders. Triggered by androgen hormones, this breeding gland (a type of mucous gland) appears as a spike ...

. It has a distinctive call, described as a "''tonk''... – ''tonk''... – ''tonk''..." sound. It occurs in "a series of 2–7 calls", with a "repetition rate of 2.02 calls/s".

Discovery

The azure-thighed tree frog was discovered in early August 2023 when six Australian

visited the region in search of "relatively rarely collected and remain poorly known" tree frogs. Its discovery was a result of them hearing its distinctive call, 30 ft (9.14 m) above them in trees near "a

waterfall A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in seve ...

on a

mountain stream A mountain stream is a Stream, brook or stream, usually with a steep gradient, flowing down a mountainside. Its swift flow rate often transports large quantities of rock (geology), rock, gravel, soil, wood or even entire Trunk (botany), logs with ...

". Two specimens were collected, and many more were heard in the same area.

DNA analysis Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

was not taken after the species discovery, but likely will in the future.

Distribution

The azure-thighed tree frog is native to the

tropical rainforest Tropical rainforests are dense and warm rainforests with high rainfall typically found between 10° north and south of the Equator. They are a subset of the tropical forest biome that occurs roughly within the 28° latitudes (in the torrid zo ...

s of the Wondiwoi Mountains of the

Wandammen Peninsula The Wondiboy Peninsula, also known as the Wondiwoi, Wandammen (spelled locally Wandamen), Wondama, or in old sources Mandamy is a mountainous peninsula in Wondama Bay Regency, Western New Guinea. It extends northwards from the Bird's Neck Isthmus ...

in northwestern Indonesian New Guinea, or

, although its range may extend into other locations. More information is needed to further analyze the species range extent.

References

{{Taxonbar, from=Q121211965 azuroscelis Amphibians of New Guinea Amphibians described in 2023