National recovery plan for Stream Frogs of South-east Queensland 2001-2005
Prepared by Harry Hines
Queensland Parks and Wildlife Service
and the South-east Queensland Threatened Frogs Recovery Team, 2002
Appendix 1. Species Profiles
Giant Barred-frog Mixophyes iteratus Straughan 1968
A very large frog (snout-vent length up to 115 mm) with a pointed snout and well developed hind legs. The dorsal surface is dark brown to olive, with darker blotches and an irregular dark vertebral band commencing between the eyes and continuing posteriorly. A dark stripe runs from the snout, through the eye and above the tympanum, terminating at a point above the forelimb. There are irregular dark spots or mottling on the flanks. The limbs have a series of dark and pale crossbars of similar width. The hidden part of the thigh ranges from black with a few large, yellow spots to being marbled black and yellow. The ventral surface is typically yellow with fine brown mottling on the chin. The pupil is vertical, while the iris is pale silvery-white to pale gold above, darker in the lower portion. The fingers lack webbing, while the toes are fully webbed, with only the last two joints of the fourth toe free. The outer metacarpal is poorly developed; the inner metatarsal tubercle is well developed, but only half as long as first toe. The skin is finely granular above, smooth below. The tympanum is distinct. (Barker et al. 1995, Cogger 1996, Straughan 1968, Meyer et al. 2001).
The call is a deep guttural grunt (Barker et al. 1995, Robinson 1993). Males call from the forest floor or from crevices under rocks, banks or overhanging tree roots (Cogger et al. 1983, Straughan 1968).
Straughan (1966) provides limited information on the reproductive biology of this species. Males call during the warmer months (September to April). Amplexus is axillary. Tadpoles are present throughout the year and probably over-winter. Laboratory reared tadpoles metamorphosed at 28-30mm. A gravid female was found to carry 4184 eggs with a mean diameter of 1.6mm (Hero and Fickling 1996).
Meyer et al. 2001 has described the tadpole. Tadpoles are large growing to over 100mm in total length. They are deep-bodied, ovoid; tail length twice that of body; eyes dorsolateral; yellow-brown above with dark spots/ splotches and dark patch at base of tail; underside silver-white; intestinal mass obscured, heart and lungs visible from below (except near metamorphosis); tail thick and muscular; low-finned; fins opaque with dark flecking (except anterior half of ventral fin); tail musculature with dark flecking/spots and/or splotches; spiracle sinistral, opening lateroventrally; vent tube opening dextral; oral disc surrounded by papillae; labial tooth row formula: 6(3-6)/3 (1).
Occurs along shallow rocky streams in rainforest, wet sclerophyll forest and farmland between 100 and 1000m (Covacevich and McDonald 1993) or deep, slow moving streams with steep banks in lowland areas (QPWS unpublished data). A short term study of the patterns of daily movement of this species during the breeding season showed that individuals moved up to 100m in a night, but not more than 20m from the stream (Lemckert and Brassil 2000). Longer term studies that include non-breeding times are required to adequately assess habitat usage of M. iteratus.
From Belli Creek near Eumundi, south-east Queensland (26° 31´S 152° 49´E), south to Warrimoo, mid-east New South Wales (33° 43´S 150° 36´E) (Hines et al. 1999) (Figure 2). Cogger (1996) states that M. iteratus was distributed south "to about Narooma" (36° 13´S 150° 08´E), but there are no specimens or other records this far south to substantiate the statement.
|Figure 2. Distribution of giant barred-frog Mixophyes iteratus.|
Hines et al. (1999) reviewed the current distribution of M. iteratus. It has suffered major declines in the southern portion of its range. There are no recent records from the Blue Mountains, although there were only a few historical records in that area. In the Watagan Mountains, M. iteratus is currently known from several small populations, but appears to have disappeared from the central and western parts of the area (White 2000). Although not common there in the past it was frequently recorded. Between the Hunter River and Macleay catchment there is currently only one known population, at Mount Seaview, but survey effort in this area has been relatively low. There were only two confirmed historical records in that area (Upper Allyn River and Middle Brother State Forest). A population was recently located in the southern Nambucca River catchment. North of this there are currently a substantial number of populations in the Dorrigo-Coffs Harbour area, North Washpool State Forest and Bungawalbin State Forest. Despite surveys in far north-east New South Wales, M. iteratus is known from only three areas - several streams in Mebbin State Forest, Peacock Ck in Richmond Range, and Rocky Creek in Nightcap Range (Goldingay et al. 1999).
In south-east Queensland, M. iteratus is currently known from scattered locations in the Mary River catchment downstream to about Kenilworth, Maroochy River, Upper Stanley River, Caboolture River, Burpengary Creek and Coomera River.
The Bunya Mountains and Cunningham's Gap previously supported M. iteratus (Straughan 1966, Australian Museum specimens) but these and nearby sites have recently been the subject of targeted survey or intensive monitoring, without locating the species. During the early 1980s, M. iteratus disappeared from two streams in the Conondale Range. It was not recorded during monitoring of these sites between 1996 and 2000. In early 2001 three M. iteratus, including a juvenile, were located during monitoring at one of these sites. This may be evidence of recovery in this section of the Conondale Range. Assessing the extent of the decline in Queensland is difficult because of the lack of historical data on its distribution and abundance.
Many sites where M. iteratus occurs are the lower reaches of streams that have had major disturbances such as clearing, timber harvesting and urban development in their headwaters. In the Dorrigo area (north-east New South Wales), Lemckert (1999) found that M. iteratus was less abundant in recently logged areas and at sites where there was little undisturbed forest. The impacts of the chytrid fungus, upstream clearing, changes in water flow regimes, degradation of water quality, feral animals, domestic stock, weed invasion and disturbance to riparian vegetation, all potential threats to current populations, are unknown. Individuals of Mixophyes iteratus have sometimes been killed in the mistaken belief that they are the introduced cane toad Bufo marinus.
Mixophyes iteratus is currently listed as Endangered in the Action Plan, nationally, and in both Queensland and New South Wales. It meets IUCN (2001) criteria for Endangered [B2ab(iii)].