On the basis of the presence of a call distinct from that of Crinia laevis (Gunther)
and the absence of hybrids in sympatry, the species C. victoriana Boulenger is reestablished.
A detailed account of the morphology, breeding biology, life history, and
geographical distribution of these species is given. Their zoogeographical position
in relation to the Bassian subregion is considered and a possible pattern of speciation
advanced.
The L. dorsalis complex is distributed extensively through coastal Australia, the
Dividing Range, and parts of the western slopes and plains. Six subspecies have been
described in the complex. Four of these are raised to species status and two additional
subspecies are described. The complex thus comprises eight taxa in all: L. dorsalis,
L. dumerili dumerili, L. d. insularis, L. d. grayi, L. d. variegatus, L, d. fryi, L. interioris,
and L. terraereginae.
The taxa were compared using two main criteria: adult male morphology and
mating-call structure. Topotypic or near-topotypic samples of each form were obtained
to ensure that comparisons were valid.
L. dorsalis is restricted to Western Australia and is disjunctly allopatric to all the
other forms in the complex. The eastern taxa have mainly parapatric distributions with
several areas of contact between them. Where the range of L. d. dumerili comes into
contact with those of L. d. insularis and L. d. variegatus, broad hybrid zones (up to
240 km wide) are formed. L. d. dumerili and L. d, grayi also appear to hybridize extensively.
Where the range of L. d. dumerili contacts that of L. interioris a narrower
hybrid zone (25-32km wide) is formed. Both L. d, dumerili and L. interioris have
achieved sympatry with L, termereginae without any evidence of hybridization.
The types of contact interactions can be related to the levels of divergence,
particularly in mating-call structure, between the forms. Thus the calls of L, d. dumerili,
L. d. insularis, L. d, grayi, and L. d. variegatus are all very similar. The call of L. interioris
is quantitatively different to that of L. d. dumerili, with a lower dominant frequency,
In arid parts of Australia the barn owl appears to feed largely on rodents which form irruptions or
plagues, i.e. undergo marked changes in abundance. Barn owls became common at the height
of an irruption of house mice, Mus musculus, in western New South Wales, but were comparatively
scarce after the mice decreased in numbers. There was some evidence that the owls' diet, determined
by analysis of pellets, was more varied immediately after the numbers of mice decreased, but its
major part still consisted of M. musculus. The mean number of prey units represented in each pellet
rose during the irruption and then declined to the original level. At a variety of sites in arid New
South Wales and South Australia, barn owls' diet consisted almost entirely of small mammals.
The most common prey species were rodents that fluctuate widely in abundance, and the mean amount
of prey per pellet differed greatly among the study sites. The feeding ecology of barn owls in arid
Australian environments is essentially similar to that described for more mesic habitats; hence, a
greatly increased variation in the abundance of mammalian prey has not led to an increase in breadth
of food niche.
The new leptodactylid genus Megistolotis and new species Megistolotis lignarius are described from localities in northern Western Australia and the Northern Territory. M. lignarius inhabits scree slopes and escarpments. The male mating call is a single note resembling the striking of timber. The spawn clump is a foam nest anchored to stones at the edge of small, temporary pools, and the tadpoles have intense black bodies and fins, and suctorial mouths. Megistolotis is most closely related to the limnodynastine genera Limnodynastes and Heleioporus.
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