Molecular studies have reported the coexistence of two species of Agarophyton in New Zealand: the newly described A.transtasmanicum with an apparently restricted distribution to some sites in the North Island, and the more widespread A.chilense. Here, we compared the distribution, genetic diversity, and structure of both Agarophyton species throughout the archipelago using sequences of the nuclear Internal Transcribed Spacer 2 (ITS2) marker. Agarophyton chilense’s distribution was continuous and extensive along the North and South Islands, Stewart Island, and Chatham Island, and the genetic clusters were mostly concordant with boundaries between biogeographic regions. In contrast, specimens of A.transtasmanicum were collected in four sites broadly distributed in both the North and South Islands, with no clear spatial structure of the genetic diversity. Populations, where the species co‐occurred, tended to display similar levels in genetic diversity for the two species. Demographic inferences supported a postglacial demographic expansion for two A.chilense genetic clusters, one present in the South Island and the eastern coast of the North Island, and the other present in northern South Island. A third genetic cluster located on the western coast of the North Island had a signature of long‐term demographic stability. For A.transtasmanicum, the skyline plot also suggested a postglacial demographic expansion. Last, we developed a new molecular tool to quickly and easily distinguish between the two Agarophyton species, which could be used to ease future fine‐scale population studies, especially in areas where the two species coexist.

中文翻译：

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新西兰群岛中两种Agarophyton物种的比较系统地理学。

分子研究报道了新西兰的两种姬松动植物共存：新近描述的A. transtasmanicum，其在北岛某些地方的分布明显受到限制，以及更广泛的A .。Chilense。在这里，我们使用核内转录间隔区2（ITS2）标记的序列比较了整个群岛上两个龙牙藻物种的分布，遗传多样性和结构。千叶Agarophyton chilense'它在北岛和南岛，斯图尔特岛和查塔姆岛的分布是连续而广泛的，其遗传簇大多与生物地理区域之间的边界一致。相比之下，在北部和南部群岛广泛分布的四个地点收集了转塔曲霉的标本，没有明确的遗传多样性空间结构。物种共存的种群倾向于在两个物种的遗传多样性上表现出相似的水平。人口推论支持两个冰期后的人口扩展一个。奇伦斯遗传簇，一个存在于南岛和北岛的东海岸，另一个存在于南岛的北部。位于北岛西海岸的第三个基因簇具有长期人口稳定的特征。对于transtasmanicum而言，天际线图也暗示了冰川后人口的扩张。最后，我们开发了一种新的分子工具，可以快速，轻松地区分两种Agarophyton物种，可用于简化未来的精细种群研究，尤其是在两种物种共存的地区。