Data from: The leafy seadragon, Phycodurus eques, a flagship species with low but structured genetic variability

The leafy seadragon (Phycodurus eques, Syngnathidae), is a charismatic endemic of Australia’s temperate coast. The species exhibits remarkable camouflage in its kelp and seagrass habitat. These habitats have been retreating throughout the range of the species, leading to concerns about the persistence of leafy seadragons. Despite being a popular aquarium display and a flagship for coastal conservation, little is known about leafy seadragon biology. We used 7 microsatellite markers and 2 mitochondrial DNA fragments to investigate the population structuring and genetic diversity of 71 individuals. Bayesian cluster analysis identified 2 main genetic partitions, one in Western Australia and the other in South Australia. Shallower, yet significant, differentiation of mitochondrial DNA (φ ST) and microsatellites (F ST, F′ ST, D) was found on the smaller geographic scales in South Australia. Distinct groups were supported in Encounter Bay, on both shores of Gulf St Vincent, and in Spencer Gulf. Sample sizes were too small in the eastern Great Australian Bight and in the westernmost locality to address genetic differentiation in these regions. Overall genetic diversity was moderate to low, but particularly low levels were found in the Western Australian cluster. This latter point needs confirmation at other sites in Western Australia. In South Australia, signatures of demographic changes were detected, which may have been caused by a population expansion due to post-glacial reflooding of the gulfs. The Western Australian and South Australian clusters appeared as demographically independent units. Conservation actions should focus on preserving genetic diversity at local scales and maintaining habitat connectivity.

叶海龙（Phycodurus eques，海龙科Syngnathidae）是澳大利亚温带海岸极具魅力的特有物种。该物种在巨藻林与海草床生境中具备极强的伪装能力。当前其栖息生境正随物种分布范围持续退缩，这引发了学界对叶海龙种群存续的担忧。尽管叶海龙是热门的水族馆展示物种，同时也是沿海保护的旗舰物种，但目前对其生物学特性仍知之甚少。本研究选用7个微卫星标记（microsatellite marker）与2段线粒体DNA（mitochondrial DNA）片段，对71个叶海龙个体的种群结构与遗传多样性展开分析。贝叶斯聚类分析（Bayesian cluster analysis）识别出两个主要的遗传聚类群：一个分布于西澳大利亚海域，另一个分布于南澳大利亚海域。在南澳大利亚海域的小地理尺度范围内，研究人员检测到线粒体DNA（φ_ST）与微卫星标记（F_ST、F′_ST、D）存在较弱但显著的遗传分化。研究证实恩康特湾（Encounter Bay）、圣文森特湾（Gulf St Vincent）两岸以及斯宾塞湾（Spencer Gulf）存在独立的遗传类群。但大澳大利亚湾东部与最西端采样点的样本量过小，无法对这些区域的遗传分化情况开展有效评估。整体遗传多样性处于中等至较低水平，其中西澳大利亚聚类群的遗传多样性尤为匮乏。这一结论仍需在西澳大利亚的其他采样位点进行验证。在南澳大利亚海域，研究人员检测到种群动态变化的遗传信号，这可能源于冰川期后海湾被重新淹没所引发的种群扩张。西澳大利亚与南澳大利亚的两个遗传聚类群呈现出独立的种群动态单元特征。相关保护工作应聚焦于维持局域尺度的遗传多样性，并保障生境连通性。