40
A . R. MAIN
northern east coast &till have the highest number of genera. I n part this
richness reflects the uniformity of the rainfall but it is also influenced
by the phyaiographic relief. Thus in northern New South Wales and
south-eastern Queeneland, where up to 10 genera are represented, mountains and plateaux of up to 5000 f t in elevation with small areas of
cIoud forests dominated by southern beech (Nothofagus nworei), descend,
on the coast side, to sub-tropical lowlands. From the top to bottom the
habitats are occupied by characteristic frogs, e.g. Kyarranus on the
top, Mixophyes in the streams, and so on, However, this area lacks any
of the New Guinea elements which are restricted to northern Queensland, e.g. Rana, Nyctimystes, Cophixalus and Sphenophryne. The four
restricted north Queensland elements are recent migrants from New
Guinea which have been unable to cross the arid corridor between
Townsvillu and Rockhampton. Such genera as Adeloeus, Lechriodus,
Mizophyes, Iiyawanus, PhiEoria, Taudactylus have no representative
outside the well-watered eastern coastal and mountainous part of
Australia. These genera are to be viewed as old elements of the Australian fauna which have been unable to invade or survive under the more
seasonai conditions prevailing over most of Australia. The restriction
is presumably a consequence of their dependence on such things as:
high raiafall, moss and sphagnum bogs (Kyarranus, Philoria), clear
streams (Tauductylzcs, Mixophyee), forest cover (Lechriodus), and cool
shaded retreats provided either by the elevation or forest cover. Of
this grolip Adelotwr is outstanding in so far as it is able to breed in roadside ditches and areas so polluted that it seems scarcely conceivable
that anything could survive, let alone breed. Nevertheless such situations are always wet, tending to be boggy, and <2debtus is obviously
limited Ly habitat requirements.
From Table I it is apparent that only two genera, both monotypic,
are restiicted to Western Australia. Myobatrachus is a burrowing
termitophile restricted to sandy soils (Calaby, 1966). Its whole life history is terrestrial and in ecology it fills the role of a caecilian. All other
frogs feed above ground. Metacrinia is a small terrestrial frog which is
restricted to wet eucalyptus forest (rainfall above 60 in./annum
(1524 mm)) where it fills the place of a salamander (Main, 1965a).
When the above 12 genera are placed in the context of habitat
requirements, viz. high and reliable rainfall or montane situations, it is
apparent that only 10 genera have radiated to occupy the arid region
which ie the most widespread Australian environment. If the 10-in.
annual minfall (254 mm) shown in Fig. 1 is taken as the boundary of
the really arid country then the surprising richness of the desert frog
fauna is revealed aa Hyla 1 sp., Notaden 1 sp., Cyclorana 2 sp., Neobatracb 3 sp., Pseudoplcryne I sp., fimnodynastes 1 sp., and Qlauertia
A . R. MAIN
northern east coast &till have the highest number of genera. I n part this
richness reflects the uniformity of the rainfall but it is also influenced
by the phyaiographic relief. Thus in northern New South Wales and
south-eastern Queeneland, where up to 10 genera are represented, mountains and plateaux of up to 5000 f t in elevation with small areas of
cIoud forests dominated by southern beech (Nothofagus nworei), descend,
on the coast side, to sub-tropical lowlands. From the top to bottom the
habitats are occupied by characteristic frogs, e.g. Kyarranus on the
top, Mixophyes in the streams, and so on, However, this area lacks any
of the New Guinea elements which are restricted to northern Queensland, e.g. Rana, Nyctimystes, Cophixalus and Sphenophryne. The four
restricted north Queensland elements are recent migrants from New
Guinea which have been unable to cross the arid corridor between
Townsvillu and Rockhampton. Such genera as Adeloeus, Lechriodus,
Mizophyes, Iiyawanus, PhiEoria, Taudactylus have no representative
outside the well-watered eastern coastal and mountainous part of
Australia. These genera are to be viewed as old elements of the Australian fauna which have been unable to invade or survive under the more
seasonai conditions prevailing over most of Australia. The restriction
is presumably a consequence of their dependence on such things as:
high raiafall, moss and sphagnum bogs (Kyarranus, Philoria), clear
streams (Tauductylzcs, Mixophyee), forest cover (Lechriodus), and cool
shaded retreats provided either by the elevation or forest cover. Of
this grolip Adelotwr is outstanding in so far as it is able to breed in roadside ditches and areas so polluted that it seems scarcely conceivable
that anything could survive, let alone breed. Nevertheless such situations are always wet, tending to be boggy, and <2debtus is obviously
limited Ly habitat requirements.
From Table I it is apparent that only two genera, both monotypic,
are restiicted to Western Australia. Myobatrachus is a burrowing
termitophile restricted to sandy soils (Calaby, 1966). Its whole life history is terrestrial and in ecology it fills the role of a caecilian. All other
frogs feed above ground. Metacrinia is a small terrestrial frog which is
restricted to wet eucalyptus forest (rainfall above 60 in./annum
(1524 mm)) where it fills the place of a salamander (Main, 1965a).
When the above 12 genera are placed in the context of habitat
requirements, viz. high and reliable rainfall or montane situations, it is
apparent that only 10 genera have radiated to occupy the arid region
which ie the most widespread Australian environment. If the 10-in.
annual minfall (254 mm) shown in Fig. 1 is taken as the boundary of
the really arid country then the surprising richness of the desert frog
fauna is revealed aa Hyla 1 sp., Notaden 1 sp., Cyclorana 2 sp., Neobatracb 3 sp., Pseudoplcryne I sp., fimnodynastes 1 sp., and Qlauertia