A new species of barred frog, Mixophyes (Anura: Myobatrachidae) from south-eastern Australia identified by molecular genetic analyses.

Mixophyes are large ground-dwelling myobatrachid frogs from eastern Australia and New Guinea. Several of the species found in mid-eastern and south-eastern Australia are listed as threatened, due largely to declines presumably caused by the amphibian disease chytridiomycosis. Given the wide distribution of several of these species and that their distributions cross well-known biogeographic boundaries that often correspond to deep genetic breaks or species boundaries among closely related vertebrates, we undertook a molecular genetic assessment of population structure across the range of each species to determine the presence of undescribed species. Of the four species of Mixophyes subject to molecular population genetic analyses, one, the Stuttering Frog (Mixophyes balbus), showed a level of diversity consistent with the presence of two species. Morphometric, meristic and bioacoustic analyses corroborate these distinctions, and a new species is described for the populations south of the Macleay River valley in mid-eastern New South Wales to east Gippsland in Victoria. Applying the IUCN Red List threat criteria the new species meets the conservation status assessment criteria for Endangered 2B1a,b because its extent of occupancy and area of occupancy are below the threshold value and it has declined and disappeared from the southern two thirds of its distribution over the past 30 years.

Molecular genetic data provide support for a model of transmission dynamics in an Australian reptile tick, Bothriocroton hydrosauri.

Bothriocroton hydrosauri is a three-host ixodid tick that infests large reptiles in southeastern Australia, where its most common host is a large scincid lizard Tiliqua rugosa. Based on previous ecological and behavioural studies of this system, we propose a 'ripple' model of tick population dynamics, where only a few female ticks succeed in producing surviving offspring. These females then are the centres of ripples of their progeny spreading into the broader landscape. The model predicts higher relatedness among larvae than among nymphs or adults on a host, and significant spatial autocorrelation in larvae extending further than for the later life stages. The model also predicts that adult ticks are likely to encounter related partners and that this will generate inbreeding within the population. We tested those predictions using nine polymorphic microsatellite loci on a sample of 848 ticks (464 larvae, 140 nymphs and 244 adults) collected from 98 lizard hosts from near Bundey Bore Station in South Australia. Our data support the predictions and indicate that the dynamics of transmission among hosts play an important role in parasite population structure.

PERMANENT GENETIC RESOURCES: Development of microsatellite markers and analysis of their inheritance in the Australian reptile tick, Bothriocroton hydrosauri.

Despite long-term study, the mechanism explaining the parapatric distribution of two Australian reptile tick species is not understood. We describe the development of primers amplifying 10 microsatellite Bothriocroton hydrosauri loci, for the study of population structure and dispersal patterns of this tick. The numbers of alleles per locus ranged from two to seven in ticks from the study site, and the observed heterozygosity between 0.28 and 0.69. Pedigree analysis indicates that one locus is inherited in a non-Mendelian manner in three families, which was not explained by null allele presence.