Hybridization Between the Western and Northern Call Races of the Limnodynastes-Tasmaniensis Complex (Anura, Myobatrachidae) on the Murray River in South Australia

1993 ◽  
Vol 41 (2) ◽  
pp. 101 ◽  
Author(s):  
JD Roberts
Keyword(s):  
Repetition Rate ◽  
South Australia ◽  
Dominant Frequency ◽  
Hybrid Zones ◽  
Hybrid Index ◽  
Hybrid Inviability ◽  
Call Structure ◽  
Murray River ◽  
Egg Number ◽  
Marne River

The Limnodynastes tasmaniensis complex consists of three call races: northern, southern and western. This paper documents differences in call structure between the western and northern races: differences in note repetition rate, dominant frequency, average number of notes per call and pulses per second note, but not in pulse repetition rate. The races also differ in egg size (smaller in northern) and egg number (higher in northern). There are zones of overlap between these two races west from Morgan and along the Marne River in South Australia. Mixed populations contain both parental and hybrid phenotypes. Hybrids were identified by a hybrid index based on the three call components that overlapped least (note repetition rate, dominant frequency and average number of notes per call). Temporary range expansions, associated with flooding on the Murray River, are documented for the northern call race. Artificial hybridisations revealed no evidence of hybrid inviability and this was supported by estimates of egg viability in field-collected egg masses from the Morgan zone of overlap. The hybrid zones are interpreted as zones of overlap with hybridisation where introgression is likely to occur. Biogeographic data suggest that the northern call race may be spreading south and west, displacing the western call race.

Studies in Australian amphibia III. The limnodynastes dorslis complex (Anura : Leptodactylidae)

1972 ◽  
Vol 20 (2) ◽  
pp. 165 ◽  
Author(s):  
AA Martin
Keyword(s):  
Western Australia ◽  
Hybrid Zone ◽  
Adult Male ◽  
Dominant Frequency ◽  
The Other ◽  
Hybrid Zones ◽  
Species Status ◽  
Call Structure ◽  
Mating Call ◽  
Male Morphology

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,

Morphology, physiology and AFLP markers validate that green box is a hybrid of Eucalyptus largiflorens and E. gracilis (Myrtaceae)

2013 ◽  
Vol 26 (2) ◽  
pp. 156 ◽  
Author(s):  
Georgia R. Koerber ◽  
Peter A. Anderson ◽  
Jack V. Seekamp
Keyword(s):  
Nitrogen Isotope ◽  
Aflp Markers ◽  
Putative Hybrid ◽  
Hybrid Index ◽  
Length Polymorphisms ◽  
Murray River ◽  
Species Specific ◽  
Mature Stands ◽  
Physiological Characters ◽  
Green Box

Prolonged drought and salinity on the Chowilla floodplain of the Murray River have caused deterioration of E. largiflorens F.Muell. A putative hybrid with E. gracilis F.Muell, green box, withstands the saline conditions. We aimed to substantiate that green box is a hybrid and to test for agreement between morphological and physiological characters with amplified fragment length polymorphisms (AFLP). Mature stands were measured for leaf, trunk, floral, cotyledon, carbon and nitrogen isotope discrimination, specific leaf area (SLA) and AFLP. Green box was placed between E. largiflorens and E. gracilis according to categorical principal components analysis (CATPCA) of 21 morphological and physiological characters and character states. The hybrid index of 11 AFLP markers that were 78% species specific separated E. gracilis and E. largiflorens, and the majority of green box plants displayed indices ranging from 0.42 to 0.53, reflecting mostly additive inheritance. Calculation of the hybrid index with all 232 AFLP markers, using maximum likelihood, similarly placed green box between E. gracilis and E. largiflorens. Our morphological, physiological and AFLP-marker observations substantiated that green box is a hybrid between E. largiflorens and E. gracilis.

scholarly journals Morphologically cryptic Amazonian bird species pairs exhibit strong postzygotic reproductive isolation

2018 ◽  
Vol 285 (1874) ◽  
pp. 20172081 ◽  
Author(s):  
Paola Pulido-Santacruz ◽  
Alexandre Aleixo ◽  
Jason T. Weir
Keyword(s):  
Reproductive Isolation ◽  
Amazon Basin ◽  
Species Recognition ◽  
Bird Species ◽  
Hybrid Zones ◽  
Hybrid Index ◽  
Postzygotic Isolation ◽  
Genome Wide ◽  
Species Pairs ◽  
Hybrid Classes

We possess limited understanding of how speciation unfolds in the most species-rich region of the planet—the Amazon basin. Hybrid zones provide valuable information on the evolution of reproductive isolation, but few studies of Amazonian vertebrate hybrid zones have rigorously examined the genome-wide underpinnings of reproductive isolation. We used genome-wide genetic datasets to show that two deeply diverged, but morphologically cryptic sister species of forest understorey birds show little evidence for prezygotic reproductive isolation, but substantial postzygotic isolation. Patterns of heterozygosity and hybrid index revealed that hybrid classes with heavily recombined genomes are rare and closely match simulations with high levels of selection against hybrids. Genomic and geographical clines exhibit a remarkable similarity across loci in cline centres, and have exceptionally narrow cline widths, suggesting that postzygotic isolation is driven by genetic incompatibilities at many loci, rather than a few loci of strong effect. We propose Amazonian understorey forest birds speciate slowly via gradual accumulation of postzygotic genetic incompatibilities, with prezygotic barriers playing a less important role. Our results suggest old, cryptic Amazonian taxa classified as subspecies could have substantial postzygotic isolation deserving species recognition and that species richness is likely to be substantially underestimated in Amazonia.

Gordon Roy Cameron, 1899-1966

1968 ◽  
Vol 14 ◽  
pp. 83-116
Keyword(s):  
Small Town ◽  
South Australia ◽  
Growing Up ◽  
Hill Country ◽  
The Bible ◽  
Murray River ◽  
The Family ◽  
The Government ◽  
Opening Up

Gordon Roy Cameron was born in Australia on 30 June 1899 at Echuca, a small town on the Victoria side of one of the bends on the Murray River. His father, George Cameron, was then a Methodist minister at a small village called Wamboota. George Cameron’s parents (Grandfather Cameron and his wife, earlier a Miss Miller) who came of hard-working farming stock in Dyce, Aberdeenshire, with forbears in Inverness and Fort Augustus, had left Aberdeen for Australia the day after their marriage early in the 1870’s and taken up land in Minlaton in St Vincent’s peninsula, South Australia. They had eleven children, of whom George Cameron was the eldest; he seems to have had a hard life on the farm. When he was twelve years old the Government of Victoria began opening up the Mallee area in northern Victoria, and he and his father each drove a wagon containing members of the family and their few goods over the 500 miles trek—much of it over uncleared scrub, desert and hill country—from Minlaton to the Mallee area, where they took up about a hundred acres of scrub to make a farm, later extended to some two thousand acres. There they and their neighbours built the mud house that still survived in 1920. Some fourteen years later the farm was going well, the younger children were growing up, and George Cameron, who had recently taken part in Bible Christian services and had developed a reputation as a local preacher, decided to join the Bible Christians as a candidate for the Ministry. In due course he was appointed to a circuit as a probationer in Horsham, North Victoria, where he met Emily Pascoe, whom he later married.

Ecological and physiological impacts of salinisation on freshwater turtles of the lower Murray River

2012 ◽  
Vol 39 (8) ◽  
pp. 705 ◽  
Author(s):  
Deborah S. Bower ◽  
Clare E. Death ◽  
Arthur Georges
Keyword(s):  
Saline Lake ◽  
South Australia ◽  
Freshwater Turtle ◽  
Plasma Sodium ◽  
Freshwater Species ◽  
Freshwater Turtles ◽  
Brackish Lake ◽  
Ecological Processes ◽  
Murray River ◽  
Chelodina Longicollis

Context The increasing intensity and extent of anthropogenically mediated salinisation in freshwater systems has the potential to affect freshwater species through physiological and ecological processes. Determining responses to salinisation is critical to predicting impacts on fauna. Aims We aimed to quantify the response of wild-caught turtles from freshwater lakes that had become saline in the lower Murray River catchment. Methods Plasma electrolytes of all three species of freshwater turtle from South Australia were compared among two freshwater sites (Horseshoe Lagoon and Swan Reach), a brackish lake (Lake Bonney) and a saline lake (Lake Alexandrina). Key results Chelodina longicollis, C. expansa and Emydura macquarii from a brackish lake had higher concentrations of plasma sodium and chloride than those from freshwater habitats. However, osmolytes known to increase under severe osmotic stress (urea and uric acid) were not elevated in brackish sites. Turtles from the highly saline lake were colonised by an invasive marine worm which encased the carapace and inhibited limb movement. Conclusions Freshwater turtles in brackish backwaters had little response to salinity, whereas the C. longicollis in a saline lake had a significant physiological response caused by salt and further impacts from colonisation of marine worms. Implications Short periods of high salinity are unlikely to adversely affect freshwater turtles. However, secondary ecological processes, such as immobilisation from a marine worm may cause unexpected impacts on freshwater fauna.

scholarly journals 3D Mapping of the Submerged Crowie Barge Using Electrical Resistivity Tomography

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Kleanthis Simyrdanis ◽  
Ian Moffat ◽  
Nikos Papadopoulos ◽  
Jarrad Kowlessar ◽  
Marian Bailey
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
South Australia ◽  
Field Studies ◽  
Resistivity Tomography ◽  
High Resolution Mapping ◽  
Murray River ◽  
Resolution Mapping ◽  
Mapping Techniques

This study explores the applicability and effectiveness of electrical resistivity tomography (ERT) as a tool for the high-resolution mapping of submerged and buried shipwrecks in 3D. This approach was trialled through modelling and field studies of Crowie, a paddle steamer barge which sunk at anchor in the Murray River at Morgan, South Australia, in the late 1950s. The mainly metallic structure of the ship is easily recognisable in the ERT data and was mapped in 3D both subaqueously and beneath the sediment-water interface. The innovative and successful use of ERT in this case study demonstrates that 3D ERT can be used for the detailed mapping of submerged cultural material. It will be particularly useful where other geophysical and diver based mapping techniques may be inappropriate due to shallow water depths, poor visibility, or other constraints.

New radiocarbon ages for the Lower Murray River, South Australia

2012 ◽  
Vol 47 (3) ◽  
pp. 157-160 ◽  
Author(s):  
CHRISTOPHER WILSON ◽  
STEWART FALLON ◽  
TOM TREVORROW
Keyword(s):  
South Australia ◽  
Murray River
Sign in / Sign up

Export Citation Format

Share Document