Fijian ground frog (Platymantis vitianus)

Fijian ground frog (Platymantis vitianus)

The Fijian ground frog (Platymantis vitianus), is, as the name describes, a ground dwelling frog. The body size (SVL ) of a Fijian ground frog ranges from 8mm as a hatchling to 107mm in adult females.

Also known as: Fijian Ground Frog

Local Names: Boto ni Viti, Dreli

Description

The Fiji ground frog, is as the name describes, a ground dwelling frog. The body size (SVL) of a Fiji ground frog ranges from 8mm as a hatchling to 107mm in adult females. The skin colour is variable, with the back of the frog ranging from a plain dark brown, to a brick red. Some individuals may have a contrasting cream coloured spot on the shoulder, a white spot on each shoulder or a white vertebral stripe running the length of the body. Frogs are NOT toads, and the Fiji frogs can be distinguished from the commonly seen, introduced and invasive cane toad (Chaunus [Bufo] marinus) by the frog’s relatively smooth and moist skin; the frog’s relatively longer hind legs and ability to leap more than 1m in distance. By comparison, cane toads can only hop very short distance of only a few centimetres.Distribution

No recruitment of young into the population due to the destruction of breeding sites (deforestation), predation of hatchlings and adults by Big-headed ants (Pheidole megacephala), cane toads and introduced mammals such as the small Indian mongoose (Herpestes javanicus), rats (Rattus spp.), and feral cats (Felis catus) are threats to the survival of Fiji’s endemic ground frogs in their current range. Even though the ground frogs are more common in forested areas, they also inhabit crop plantations, and have been accidentally killed by farmers whilst burning and clearing their plantations or when removing piled up felled trees and coconut husks. Unlike the cane toad, Fiji’s endemic frogs are highly vulnerable to desiccation (drying out). Fijian ground frog activities are thus restricted to shady, forested areas with abundant leaf litter, rotting logs and piled coconut husks in which they take refuge during the day and when escaping predators.

Habitat Ecology and Behaviour

Fiji’s endemic frogs are terrestrial breeders, and undergo direct development. That is, tiny froglets or miniature frogs, rather than tadpoles, emerge from hatched eggs.

Fiji’s ground frogs are nocturnal animals and search for mates and forage for food (insects) at night along the forest floor, on fallen logs, on young plants (saplings), in plantations, within village areas and in coastal vegetation. Although they predominantly are found on the ground, Fiji ground frogs have also been observed on tree branches, as high as 2m above the ground. Fijian ground frogs have a unique call – a short sharp whistle, and on the island of Viwa, they can be heard calling early in the evening (especially after rain) till early morning.

Threats

No recruitment of young into the population due to the destruction of breeding sites (deforestation), predation of hatchlings and adults by Big-headed ants (Pheidole megacephala), cane toads and introduced mammals such as the small Indian mongoose (Herpestes javanicus), rats (Rattus spp.), and feral cats (Felis catus) are threats to the survival of Fiji’s endemic ground frogs in their current range. Even though the ground frogs are more common in forested areas, they also inhabit crop plantations, and have been accidentally killed by farmers whilst burning and clearing their plantations or when removing piled up felled trees and coconut husks. Unlike the cane toad, Fiji’s endemic frogs are highly vulnerable to desiccation (drying out). Fijian ground frog activities are thus restricted to shady, forested areas with abundant leaf litter, rotting logs and piled coconut husks in which they take refuge during the day and when escaping predators.

Conservation Status

In addition to their current range, the Fijian ground frogs historically occurred all over Vanua Levu, Viti Levu and Beqa – from these islands specimens have been collected. It was also recorded on Kadavu, Moturiki and Koro but these are anecdotal records not supported by voucher specimens. Recent research work into the conservation of the FGF has been led by the USP and is currently focused on the population on Viwa island; its conservation status on all other islands where it is found; a captive breeding program (with KulaEco Park); phylogenetic research into the origins of Fiji’s endemic frogs and ecological (in-situ and ex-situ) research. FGF eggs were only found in the wild for the first time in December 2007.

 FROG 8909 Platymantis vitiana, captive specimen from Viwa Island, Photo: Paddy Ryan

FROG 8909 Platymantis vitiana, captive specimen from Viwa Island, Photo: Paddy Ryan

 Fiji ground frog map

Fiji ground frog map

 

Remarks and Cultural Significance

In addition to their current range, the Fijian ground frogs historically occurred all over Vanua Levu, Viti Levu and Beqa – from these islands specimens have been collected. It was also recorded on Kadavu, Moturiki and Koro but these are anecdotal records not supported by voucher specimens. Recent research work into the conservation of the FGF has been led by the USP and is currently focused on the population on Viwa island; its conservation status on all other islands where it is found; a captive breeding program (with KulaEco Park); phylogenetic research into the origins of Fiji’s endemic frogs and ecological (in-situ and ex-situ) research. FGF eggs were only found in the wild for the first time in December 2007.

References

Brown 2004;
Gorham 1968, 1971;
Graeffe 1986;
Kuruyawa et al. 200);
Morrison 2003; 2005;
Narayan et al. 2004; 2007;
Ryan 1984;
Ryan 2000;
Thomas 2007;
Watson 1960;
Worthy 2001;
Young et al. 2006;
Zug et al. 2004.

Front Page Photo: Nunia Thomas – a large female Fijian ground frog perched on fallen coconut leaves; on Viwa Island in Tailevu