Green-eyed Tree Frog
Litoria genimaculata (Horst, 1883)

Family: Hylidae - Tree Frogs

Order: Anura - Frogs

Class: Amphibia

Phylum: Chordata - Vertebrates

Kingdom: Animalia

Red List status: Least Concern

Green-eyed frog, Kirrama State Forest, Queensland, Australia

                       Male        Female

Adult length:  37-54 mm  58-80 mm

Tadpole length: 15 mm

RANGE

As currently defined, Litoria genimaculata occurs from the western islands of New Guinea and throughout the island's centre, with a separate population ranging from Big Tableland south to Paluma in Australia. The species is replaced in Australia's Cape York peninsula by a species included within L. eucnemis.

See Taxonomy for an explanation of the green-eyed frog's disjunct distribution.

Range           Description            Habitat            Behaviour            Status            Taxonomy            REFERENCES

Other common names: New Guinea tree frog, fringed tree frog

 

 

DESCRIPTION


Adult:
A moderately robust tree frog with a blunt, rounded snout, long legs and highly expanded toe discs. The toes are almost fully webbed; fingers are about half-webbed. The tympanum is visible, and the supratympanic fold is indistinct. Males lack a vocal sac. The skin is smooth or finely granular. The species' most distinctive feature is the presence of a prominent skin flap with a serrated edge running the length of the hindlimb; a less distinct fringe occurs on the arms. The body colour is grey or silver to brown to orange, and with brown mottling; some specimens exhibit extensive patches of green patterning, reminiscent of lichen. The underside is white, the groin is mottled black and cream, and the throat is densely speckled in brown. The hindlimbs are often barred, although this may be indistinct, and there may be a dark band on top of the head between the eyes. The iris of the eye itself is silver in Australian forms (described as gold in New Guinean specimens - Menzies, 2006), contrasting with a green ring or crescent around the rim of the eye and sometimes colouring the upper iris in most specimens.

 

Tadpole: Light brown or grey above, with a dark stripe running across the rear of the body, and a pale underside. Eyes are located at the sides of the head.  The upper portion of the tail is speckled black.

 

Eggs: Small and black, laid in a large clump (up to 843 eggs have been recorded) in shallow water.

 

Call: Described as a soft, "slow to medium-paced series of 'tocs'" (Hoskin & Hero, 2008), which can be hard to hear over the sound of running water.

 

 

Similar species: The serrated hindlimbs, cryptic colouration and green eye ring preclude confusion with most Australian tree frogs. The recently-described Kuranda tree frog (L. myola) is typically smaller and more slender, but is mostly distinguishable by its small distribution confined to the Kuranda area near Cairns, and by its faster, higher-frequency call. Litoria eucnemis is larger and can most reliably be distinguished by its call. Litoria amboinensis has silver irises with no green colouration. L. impura and L. flavescens exhibit similar iris colouration, but lack a serrated fringe. Males of most other species possess vocal sacs.

 

 

HABITAT

Call recording Jean-Marc Hero. Used with permission.

A forest species, occurring in both rainforest and adjacent wet eucalypt forest. Males are stream-associated, and are usually found on rocks or low vegetation. Females may occur throughout the forest, and may climb high into the canopy. In New Guinea, the species is associated with hill forest.

Reproductive habitat: Streams, where animals breed in slow-moving sections or still pools. Eggs may also be laid in temporary pools.

Elevation: 0-1,500 m; in New Guinea it may occur at sea level, but rarely below 100 m in Australia

 

BEHAVIOUR

Predominantly arboreal, commonly being found in trees along streams. In New Guinea, larvae have been observed clinging to rocks rather than swimming in open water.

Breeding season: Animals typically begin breeding in Australia in September, but breeding may begin as early as August. Equivalent data for New Guinea are not available.

 

STATUS

Concurrent with a decline tropical Australian stream frogs at high altitudes in the 1990s attributed to fungal infection, the green-eyed frog had declined in or disappeared from higher elevations within its range by 1994. To date, L. genimaculata is the only such species to have recolonised much its former range. This appears to be a consequence of behaviour modification to reduce exposure to the disease, as the fungus remains lethal to affected individuals. Despite this apparent recovery, as a consequence of the initial decline Litoria genimaculata is classified as nationally Rare in Australia, and populations are believed to be declining (Alford et al, 2004).

 

TAXONOMY

The currently recognised range of L. genimaculata contains at least three genetically distinct species, with two recognised Australian populations distinct both from those in New Guinea and from one another. The two Australian populations ("northern" and "southern") were recently retained as L. genimaculata despite the recognition of a third member of the lineage confined to the area around Kuranda.

Although it is likely that these two populations will be recognised as distinct from one another and from the disjunct New Guinean population (with Australian "Litoria eucnemis" possibly representing a further new species), the correct species name to apply in the meantime is a source of confusion. Hoskin & Hero (2008) use the available name Litoria serrata for both Australian lineages presently included within L. genimaculata. However, most authorities still combine the Australian and New Guinean forms within L. genimaculata (Frost, 2009; Hoskin, 2007; Menzies, 2006). Frost (2009) considers L. serrata to be a synonym for L. eucnemis.

 

REFERENCES

 

Wildlife of Tropical Queensland, The Queensland Museum 2000

Alford, R., Cunningham, M., McDonald, K., Richards, S. & Price, D. (2004). Litoria genimaculata. In: IUCN 2008. 2008 IUCN Red List of Threatened Species.

Frost, D.R. (2009) Amphibian Species of the World: an Online Reference. Version 5.3

Hoskin, C.J. (2007) Description, biology and conservation of a new species of Australian tree frog (Amphibia: Anura: Hylidae: Litoria) and an assessment of the remaining populations of Litoria genimaculata Horst, 1883: systematic and conservation implications of an unusual speciation event Biological Journal of the Linnean Society 91: 549-563

Hoskin, C. & Hero, J-M. (2008) Rainforest Frogs of the Wet Tropics, north-east Australia. Griffith University, Gold Coast, Australia: 85 pp

Menzies, J. (2006) The Frogs of New Guinea and The Solomon Islands. Pensoft, Bulgaria: 346pp