Barcodes Reveal 48 New Species of Tetrahymena, Dexiostoma, and Glaucoma: Phylogeny, Ecology, and Biogeography of New and Established Species
Barcodes Reveal 48 New Species of Tetrahymena, Dexiostoma, and Glaucoma: Phylogeny, Ecology, and Biogeography of New and Established Species
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DOI：
10.1111/jeu.12642
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发表时间：
2019-01-01
影响因子：
2.2
通讯作者：
Doerder, F. Paul
中科院分区：
文献类型：
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作者：
Doerder, F. Paul
四膜虫线粒体cox1条形码和核SSUrRNA序列在区分其许多隐种方面特别有效。为了进一步了解四膜虫的自然历史，将近1000株淡水类四膜虫分离株中的大部分归为已建立的四膜虫种，其余归为37个四膜虫新种、9个Dexiostoma新种和12个青光眼新种。在系统发育上，除了三种四膜虫外，所有四膜虫都属于公认的“australis”或“borealis”分支；少数人形成了一个发散的“副兽类”分支。大多数四膜虫物种是微核的，但其他物种完全是微核的。LSUrRNA前体的自剪接内含子在Dexiostoma和青光眼中不存在，可能是在australis/borealis分裂后获得的；在某些情况下，它的序列是物种的诊断。美洲四膜虫、埃利奥特绦虫、格鲁奇绦虫和北方四膜虫共占分离株的50%，与先前对已确定物种的调查结果一致。以前在奥地利、中国和巴基斯坦发现的物种的生物地理范围扩展到新北极；部分种表现出与地方性相一致的种群结构。大多数物种最常从池塘或湖泊中采集，而其他物种，特别是Dexiostoma物种最常从溪流或河流中采集。结果表明，可能还有数百种物种有待发现，特别是如果收集是全球性的，并且包括寄生形式的宿主。
Tetrahymena mitochondrial cox1 barcodes and nuclear SSUrRNA sequences are particularly effective at distinguishing among its many cryptic species. In a project to learn more about Tetrahymena natural history, the majority of >1,000 Tetrahymena-like fresh water isolates were assigned to established Tetrahymena species with the remaining assigned to 37 new species of Tetrahymena, nine new species of Dexiostoma and 12 new species of Glaucoma. Phylogenetically, all but three Tetrahymena species belong to the well-established "australis" or "borealis" clades; the minority forms a divergent "paravorax" clade. Most Tetrahymena species are micronucleate, but others are exclusively amicronucleate. The self-splicing intron of the LSUrRNA precursor is absent in Dexiostoma and Glaucoma and was likely acquired subsequent to the "australis/borealis" split; in some instances, its sequence is diagnostic of species. Tetrahymena americanis, T. elliotti, T. gruchyi n. sp., and T. borealis, together accounted for >50% of isolates, consistent with previous findings for established species. The biogeographic range of species found previously in Austria, China, and Pakistan was extended to the Nearctic; some species show evidence of population structure consistent with endemism. Most species were most frequently collected from ponds or lakes, while others, particularly Dexiostoma species, were collected most often from streams or rivers. The results suggest that perhaps hundreds of species remain to be discovered, particularly if collecting is global and includes hosts of parasitic forms.