1
|
Lungfish and the Long Defeat. DIVERSITY 2023. [DOI: 10.3390/d15010063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Australia has an excellent fossil record of lungfish that begins in the Devonian and includes many species in Tertiary and Quaternary deposits. The extant Australian lungfish, Neoceratodus forsteri, occurs in Pliocene deposits, but is now restricted to a handful of coastal rivers in Queensland. Some of the fossil taxa, belonging to species related to N. forsteri, are represented by only a few specimens, but others include large numbers of tooth plates. The existence of these taxa, even if they are represented by only a few specimens, indicates that lungfish were present in lakes and rivers in central and northern Australia in the past, and that the potential habitats for these fish were more extensive then than they are now. Many of the fossil populations died out because Australia became more arid, and the remaining species became isolated in large river systems in the north and east of the continent. However, the cause of extinction of some fossil populations was not always related to increasing aridity. Several fossil populations were apparently living in poor conditions. They stopped spawning and adding new members to the population. The remaining individuals showed advanced age and many diseases before the population disappeared. This can be observed in the present day, and one population in an isolated reservoir is already extinct.
Collapse
|
2
|
Fallon SJ, McDougall AJ, Espinoza T, Roberts DT, Brooks S, Kind PK, Kennard MJ, Bond N, Marshall SM, Schmidt D, Hughes J. Age structure of the Australian lungfish (Neoceratodus forsteri). PLoS One 2019; 14:e0210168. [PMID: 30673738 PMCID: PMC6343868 DOI: 10.1371/journal.pone.0210168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 12/18/2018] [Indexed: 11/22/2022] Open
Abstract
The Australian lungfish has been studied for more than a century without any knowledge of the longevity of the species. Traditional methods for ageing fish, such as analysis of otolith (ear stone) rings is complicated in that lungfish otoliths differ from teleost fish in composition. As otolith sampling is also lethal, this is not appropriate for a protected species listed under Australian legislation. Lungfish scales were removed from 500 fish from the Brisbane, Burnett and Mary rivers. A sub–sample of scales (85) were aged using bomb radiocarbon techniques and validated using scales marked previously with oxytetracycline. Lungfish ages ranged from 2.5–77 years of age. Estimated population age structures derived using an Age Length Key revealed different recruitment patterns between river systems. There were statistically significant von Bertalanffy growth model parameters estimated for each of the three rivers based on limited sample sizes. In addition, length frequency distributions between river systems were also significantly different. Further studies will be conducted to review drivers that may explain these inter-river differences.
Collapse
Affiliation(s)
- Stewart J. Fallon
- Research School of Earth Sciences, The Australian National University, Canberra, ACT, Australia
- * E-mail:
| | - Andrew J. McDougall
- Queensland Department of Natural Resources, Mines and Energy, Bundaberg, QLD, Australia
| | - Tom Espinoza
- Queensland Department of Natural Resources, Mines and Energy, Bundaberg, QLD, Australia
| | | | - Steven Brooks
- Queensland Department of Agriculture and Fisheries, Brisbane, QLD, Australia
| | - Peter K. Kind
- Queensland Department of Agriculture and Fisheries, Brisbane, QLD, Australia
| | | | - Nick Bond
- Griffith University, Brisbane, QLD, Australia
- The Murray-Darling Basin Freshwater Research Centre, Latrobe University, Albury-Wodonga, Victoria, Australia
| | - Sharon M. Marshall
- Queensland Department of Natural Resources, Mines and Energy, Bundaberg, QLD, Australia
| | - Dan Schmidt
- Griffith University, Brisbane, QLD, Australia
| | - Jane Hughes
- Griffith University, Brisbane, QLD, Australia
| |
Collapse
|
3
|
Schmidt DJ, Fallon S, Roberts DT, Espinoza T, McDougall A, Brooks SG, Kind PK, Bond NR, Kennard MJ, Hughes JM. Monitoring age-related trends in genomic diversity of Australian lungfish. Mol Ecol 2018; 27:3231-3241. [PMID: 29989297 DOI: 10.1111/mec.14791] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/28/2018] [Accepted: 07/01/2018] [Indexed: 11/28/2022]
Abstract
An important challenge for conservation science is to detect declines in intraspecific diversity so that management action can be guided towards populations or species at risk. The lifespan of Australian lungfish (Neoceratodus forsteri) exceeds 80 years, and human impacts on breeding habitat over the last half century may have impeded recruitment, leaving populations dominated by old postreproductive individuals, potentially resulting in a small and declining breeding population. Here, we conduct a "single-sample" evaluation of genetic erosion within contemporary populations of the Australian lungfish. Genetic erosion is a temporal decline in intraspecific diversity due to factors such as reduced population size and inbreeding. We examined whether young individuals showed signs of reduced genetic diversity and/or inbreeding using a novel bomb radiocarbon dating method to age lungfish nonlethally, based on 14 C ratios of scales. A total of 15,201 single nucleotide polymorphic (SNP) loci were genotyped in 92 individuals ranging in age from 2 to 77 years old. Standardized individual heterozygosity and individual inbreeding coefficients varied widely within and between riverine populations, but neither was associated with age, so perceived problems with recruitment have not translated into genetic erosion that could be considered a proximate threat to lungfish populations. Conservation concern has surrounded Australian lungfish for over a century. However, our results suggest that long-lived threatened species can maintain stable levels of intraspecific variability when sufficient reproductive opportunities exist over the course of a long lifespan.
Collapse
Affiliation(s)
- Daniel J Schmidt
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
| | - Stewart Fallon
- Radiocarbon Facility, Research School of Earth Sciences, The Australian National University, Canberra, ACT, Australia
| | | | - Thomas Espinoza
- Department of Natural Resources and Mines, Bundaberg, Qld, Australia
| | - Andrew McDougall
- Department of Natural Resources and Mines, Bundaberg, Qld, Australia
| | - Steven G Brooks
- Queensland Department of Agriculture, Fisheries and Forestry, Brisbane, Qld, Australia
| | - Peter K Kind
- Queensland Department of Agriculture, Fisheries and Forestry, Brisbane, Qld, Australia
| | - Nick R Bond
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
- The Murray-Darling Basin Freshwater Research Centre, Latrobe University, Albury-Wodonga, Vic, Australia
| | - Mark J Kennard
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
| | - Jane M Hughes
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
| |
Collapse
|
4
|
Bishop CR, Hughes JM, Schmidt DJ. Mitogenomic analysis of the Australian lungfish (Neoceratodus forsteri) reveals structuring of indigenous riverine populations and late Pleistocene movement between drainage basins. CONSERV GENET 2017. [DOI: 10.1007/s10592-017-1034-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
5
|
Cranial nerves in the Australian lungfish, Neoceratodus forsteri, and in fossil relatives (Osteichthyes: Dipnoi). Tissue Cell 2017; 49:45-55. [DOI: 10.1016/j.tice.2016.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 11/24/2022]
|
6
|
Kemp A, Heaslop M, Carr A. Scale structure in the Australian lungfish,Neoceratodus forsteri(Osteichthyes: Dipnoi). J Morphol 2015. [DOI: 10.1002/jmor.20399] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Anne Kemp
- School of Environment and the School of Biomolecular and Physical Sciences; Griffith University; 170 Kessels Road Nathan Queensland 4111 Australia
| | - Meg Heaslop
- Centre for Microscopy and Microanalysis, University of Queensland; St. Lucia Queensland 4072
| | - Andrew Carr
- Centre for Microscopy and Microanalysis, University of Queensland; St. Lucia Queensland 4072
| |
Collapse
|
7
|
Extremely low microsatellite diversity but distinct population structure in a long-lived threatened species, the Australian lungfish Neoceratodus forsteri (Dipnoi). PLoS One 2015; 10:e0121858. [PMID: 25853492 PMCID: PMC4390199 DOI: 10.1371/journal.pone.0121858] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/16/2015] [Indexed: 11/24/2022] Open
Abstract
The Australian lungfish is a unique living representative of an ancient dipnoan lineage, listed as ‘vulnerable’ to extinction under Australia’s Environment Protection and Biodiversity Conservation Act 1999. Historical accounts indicate this species occurred naturally in two adjacent river systems in Australia, the Burnett and Mary. Current day populations in other rivers are thought to have arisen by translocation from these source populations. Early genetic work detected very little variation and so had limited power to answer questions relevant for management including how genetic variation is partitioned within and among sub-populations. In this study, we use newly developed microsatellite markers to examine samples from the Burnett and Mary Rivers, as well as from two populations thought to be of translocated origin, Brisbane and North Pine. We test whether there is significant genetic structure among and within river drainages; assign putatively translocated populations to potential source populations; and estimate effective population sizes. Eleven polymorphic microsatellite loci genotyped in 218 individuals gave an average within-population heterozygosity of 0.39 which is low relative to other threatened taxa and for freshwater fishes in general. Based on FST values (average over loci = 0.11) and STRUCTURE analyses, we identify three distinct populations in the natural range, one in the Burnett and two distinct populations in the Mary. These analyses also support the hypothesis that the Mary River is the likely source of translocated populations in the Brisbane and North Pine rivers, which agrees with historical published records of a translocation event giving rise to these populations. We were unable to obtain bounded estimates of effective population size, as we have too few genotype combinations, although point estimates were low, ranging from 29 - 129. We recommend that, in order to preserve any local adaptation in the three distinct populations that they be managed separately.
Collapse
|
8
|
Cooper P. Evolution and adaptation: a tribute to Richard Essex Barwick. AUST J ZOOL 2014. [DOI: 10.1071/zov62n1_in] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|