Xenopus fraseri: Mr. Fraser, where did your frog come from?
Xenopus fraseri: Mr. Fraser, where did your frog come from?
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DOI：
10.1371/journal.pone.0220892
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发表时间：
2019-09-11
期刊：
影响因子：
3.7
通讯作者：
Blackburn, David C.
中科院分区：
文献类型：
--
作者：
Evans, Ben J.;Gansauge, Marie-Theres;Blackburn, David C.
一个全面、准确和可修订的阿尔法分类法对于生物多样性研究至关重要，但当参考标本的数据难以收集或观察时，这是一个挑战。然而，最近的技术进步可以克服其中一些挑战。为了说明这一点，我们使用现代方法来解决一个由弗雷泽爪蛙提出的百年分类之谜，包括X。fraseri与其他物种不同，如果是这样的话，它在地理上和遗传学上的位置也不同。为了促进这些推论，我们使用高分辨率技术来检查形态变异，我们生成并分析了所有非洲爪蟾物种的完整线粒体基因组序列，包括> 150岁的模式标本。结果表明，X. fraseri确实与其他物种不同，坚定地将该物种置于系统发育背景中，并确定其在加纳北方和喀麦隆北方的最小地理分布。这些数据也允许新的系统发育分辨率到这个深入研究和生物医学上的重要群体。非洲爪蟾（Xenopus fraseri）以前被认为是一种热带雨林特有种，与amieti物种群中的物种并列;事实上，这个物种出现在萨赫勒边界的干旱栖息地，是muelleri物种群中最小的成员。这项研究表明，弗雷泽蛙的分类之谜是稀疏的收集记录，种间保护和种内多态性的外部解剖，和模式标本与不寻常的形态相结合的结果。
A comprehensive, accurate, and revisable alpha taxonomy is crucial for biodiversity studies, but is challenging when data from reference specimens are difficult to collect or observe. However, recent technological advances can overcome some of these challenges. To illustrate this, we used modern approaches to tackle a centuries-old taxonomic enigma presented by Fraser's Clawed Frog, Xenopus fraseri, including whether X. fraseri is different from other species, and if so, where it is situated geographically and phylogenetically. To facilitate these inferences, we used high-resolution techniques to examine morphological variation, and we generated and analyzed complete mitochondrial genome sequences from all Xenopus species, including > 150-year-old type specimens. Our results demonstrate that X. fraseri is indeed distinct from other species, firmly place this species within a phylogenetic context, and identify its minimal geographic distribution in northern Ghana and northern Cameroon. These data also permit novel phylogenetic resolution into this intensively studied and biomedically important group. Xenopus fraseri was formerly thought to be a rainforest endemic placed alongside species in the amieti species group; in fact this species occurs in arid habitat on the borderlands of the Sahel, and is the smallest member of the muelleri species group. This study illustrates that the taxonomic enigma of Fraser's frog was a combined consequence of sparse collection records, interspecies conservation and intraspecific polymorphism in external anatomy, and type specimens with unusual morphology.