KYARRANUS FROM THE TERTIARY OF QUEENSLAND 
49 
Ilium Length (mm) 
Fig. 3. Length of ilia of Kyarranus species plotted 
against snout to vent length. Assumed snout to vent 
length of largest specimen of fossil species indicated by 
broken lines, t- value for slope 6.365, p < 0.001. For x 
= 16.1. y = 37.9 (95% confidence limits = 36.8-38.2). 
Closed squares = K. loveridgei ; open squares — K 
sphagnicoius; closed circle = K. kundagungan. 
DISCUSSION 
Discovery of Kyarranus in the Tertiary of north¬ 
ern Queensland is significant in its contribution 
to an understanding of the origin and dispersal 
of Australian frogs and the palaeoen vironmental 
implications. Extant Kyarranus are confined to 
three isolated montane areas which are vari¬ 
ously forested, and where there is a carpet of low 
growing vegetation and decomposing material 
within which the frogs live and deposit spawn. 
The three extant Kyarranus species are allo- 
patric and clustered around the eastern extrem¬ 
ity of the Queensland-New South Wales border 
(Fig. 4). The evident close phylogenetic relation¬ 
ship to Philoria that has caused the status of 
Kyarranus to be questioned indicates that a 
shared ancestral stock once extended through 
New South Wales and eastern Victoria. 
The presence of K. borealis in the Tertiary of 
northwestern Queensland indicates a much 
more widespread geographic distribution than 
has been appreciated, and emphasises the relict 
nature of the extant populations. Extinction in 
the northwest and intermediate areas can be at¬ 
tributed to the first onset of aridity. However, 
the existence at the Riversleigh sites raises the 
question of why this genus did not extend its 
range farther north into New Guinea when op¬ 
portunities arose. 
Fig. 4. Geographic distribution of species of Kyar¬ 
ranus and Philoria . The extent of K sphagnicoius so far 
south is based on locality records of Webb (1989). 
A partial parallel is the distribution of Lech- 
riodus Boulenger which is abundant at Rivers¬ 
leigh sites but exhibits a similar gap to the 
northern limit of the (single) extant species 
(Tyler 1989, Tyler et al. 1990). However, Lech- 
riodus has three extant species in New Guinea. 
