Orange-Crowned (Western) Toadlet Pseudophryne occidentalis

 

Introduction

The western or orange-crowned toadlet is found in the southwest and arid zones of WA, from Hamelin Pool, south to Morowa, Bruce Rock and Israelite Bay. P. occidentalis replaces P. guentheri on the eastern side of its range (Tyler et al., 1994). The appearance of P. occidentalis has been described by Tyler et al. This species is a small, robust frog with short legs. It is quite variable in appearance, but the typical holotype is chocolate brown with bright orange markings on the forehead, upper arms and above the cloaca. Specimens may also be light tan in appearance, with faint yellow markings instead of bright orange (personal observation). The ventral surface is diagnostic, consisting of black areas on a bold white background. The size range of frogs is 22-24 mm for males and 21-26 mm for females (Tyler et al., 1994).
 

Breeding and Feeding

The western toadlet is similar in many respects to the closely related Guenther's toadlet P. guentheri, including its call, which  is described as short and grating (Tyler et al., 1994). Breeding in this species is opportunistic and dictated by the presence of semi-permanent pools of water, especially around granite outcrops and areas of underlying rock. The development of this frog is truly unique, and is partially terrestrial. Eggs are laid in burrows near a water source, during autumn and early winter. The permanent or temporary water sources eventually rise during winter, thus flooding the burrows and flushing out the eggs which will then develop directly into metamorphs. The diet of this species has not been studied, but is likely to consist of ground dwelling insects.
 

Conservation

This species is currently one of the most widespread and common frogs in the drier parts of southwest Western Australia. It is common throughout the wheatbelt and areas north of Perth. It is unlikely to be endangered in the near future, but studies have shown that habitat fragmentation (caused by land clearance) in the wheatbelt, has the potential to lead to declines of populations in small fragments (Davis, 1997).
 

References

Davis, R.A. (1997) The effects of habitat fragmentation on frog populations in the wheatbelt of Western Australia. Unpublished honours thesis. Murdoch University.

Tyler, M.J., Smith, L.A. and Johnstone, R.E. (1994) Frogs of Western Australia. Western Australian Museum, Perth.
 

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Created: 11/3/98.
Updated: 23/10/98.