Mitochondrial variation among Australian freshwater turtles (genus Myuchelys), with special reference to the Endangered M. bellii 

Abstract

Identifying species and the relationships among them remains important for assessing biodiversity trends and is a critical focus for reversing global biodiversity loss. The saw-shelled turtles of Australia, in the genus Myuchelys, show cryptic diversity and include species that range from Endangered (M. bellii), through those that are locally abundant but extremely limited in distribution (M. georgesi and M. purvisi) to those that are common and widespread (M. latisternum). The Endangered M. bellii is restricted to 3 small isolated populations in the headwaters of the Murray-Darling basin, in the Border, Gwydir and Namoi tributaries. There is no evidence of strong differentiation among these 3 populations based on mitochondrial DNA (mtDNA) divergences; rather there is only a shallow genetic structure ranging from 0.1 to 0.3% divergence. The 3 restricted and small populations of the Endangered M. bellii face a number of threatening processes and require conservation management across state boundaries as a single biological species. The mtDNA phylogeny supports previous phylogenetic findings of a deep phylogenetic divergence between M. purvisi and M. georgesi (13.5% mtDNA) and the sister taxa relationship of M. latisternum and M. bellii. A notable exception was our finding that Emydura macquarii and M. georgesi are sister taxa inside the Myuchelys radiation.

Phylogenetic Uncertainty and Taxonomic Re-revisions: An Example from the Australian Short-necked Turtles (Testudines: Chelidae)

“…Georges et al (1999) recovered Myuchelys as paraphyletic with respect to Elseya based on analyses of two mitochondrial genes (12S rRNA and 16S rRNA), but without statistical support. More recently, analyses of a single nuclear locus (c-mos) provided moderate support (83% bootstrap support values) for grouping Emydura macquarii, M. latisternum, and M. georgesi as a clade to the exclusion of M. purvisi, a result confirmed by analysis of mtDNA (Fielder et al, 2012). However, Georges and Adams (1996), Georges et al (1999), and Fielder et al (2012) all recognized that the uncertainty surrounding incongruence among these analyses should preclude taxonomic revisions and therefore did not propose revisions to correct the potential paraphyly of Myuchelys with respect to Emydura.…”

Contemporary genetic structure of an endemic freshwater turtle reflects Miocene orogenesis of New Guinea

“…commun. ; TCR500, Engstrom, Shaffer & McCord, 2002), 533 bp of the NADH dehydrogenase subunit 4 (ND4), a further 70 bp of ND4 coding region, together with 71 bp of tRNA His, 59 bp of tRNA Ser, and the first 47 bp of tRNA Leu [primers ND4: Arévalo, Davis & Sites (1994); ND4Int: Fielder et al (2012); Leu+G 5′-GCATTACTTTTACTTGGATTTGCA CCA-3′ sensu Arévalo et al (1994)]. For each DNA fragment, two products from two independent reactions were sequenced in both directions to ensure sequence fidelity.…”

Contemporary genetic structure reflects historical drainage isolation in an Australian snapping turtle,Elseya albagula

“…Freshwater turtles were early models for understanding biogeographical patterns (Walker & Avise, ) and often show high levels of cryptic lineage diversity (Roman et al ., ; Spinks & Shaffer, ; Pearse et al ., ). Australian species, however, are poorly studied and often neglected in evolutionary studies and in management planning (Georges, ; Fielder et al ., ), yet they are a diverse and evolutionarily distinct group consisting almost exclusively of members of the family Chelidae. The mid‐eastern coastal catchments of the Fitzroy, Burnett, and Mary Rivers support the second highest turtle diversity (seven species) and the greatest concentration of local endemics (three species) in Australia.…”