ABSTRACT Shell shape varies markedly in freshwater mussels in the order Unionoida. Freshwater mussels belonging to the genus Velesunio (Family Hyriidae) are distributed widely in the rivers and wetlands of Australia, with recent molecular evidence suggesting at least three more species within the genus Velesunio than previously described using shell morphology. This study explored differences in shell morphology between and within two major Australian drainage basins: the Murray–Darling and Lake Eyre. Differences in shell shape among the species were difficult to detect with variability in morphology, showing the greatest difference between drainage basins. For all species, there were significant differences in morphology between rivers within basins; Shells from the Lake Eyre Basin, showed small differences in shell morphology among with greater species level differences in morphology at the site scale in the Murray–Darling Basin. Extreme flow variability of Lake Eyre Basin rivers means they spend considerable time as lentic waterholes. In contrast, the rivers of the Murray–Darling Basin, while still highly variable, spend a far greater time under flowing conditions. Thus, the variability in shell morphology among sites may reflect local hydraulic variability rather than large-scale flow variability.

中文翻译：

---

一些澳大利亚淡水贻贝（Unionoida，Hyriidae）壳形态的可变可塑性

摘要：Unionoida 目淡水贻贝的壳形状变化很大。淡水贻贝属于 Velesunio（贻贝科）广泛分布在澳大利亚的河流和湿地中，最近的分子证据表明 Velesunio 属内的物种至少比之前使用贝壳形态描述的多三个。这项研究探讨了澳大利亚两个主要流域之间和内部的贝壳形态差异：墨累-达令和艾尔湖。物种间贝壳形状的差异难以检测，形态上的变异性，显示流域之间的差异最大。对于所有物种，流域内河流之间的形态存在显着差异；来自艾尔湖盆地的贝壳，在墨累-达令盆地的场地尺度上，贝壳形态的差异很小，物种水平的形态差异较大。艾尔湖盆地河流的极端流量变化意味着它们花费了大量时间作为静水坑。相比之下，墨累-达令盆地的河流虽然仍然变化很大，但在流动条件下花费的时间要长得多。因此，站点间壳形态的变化可能反映了局部水力变化而不是大规模流量变化。