Scoble Josephine Margaret, Cavalier-Smith Thomas
Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
Eur J Protistol. 2014 Oct;50(5):551-92. doi: 10.1016/j.ejop.2014.08.001. Epub 2014 Aug 19.
Heterotrophic chrysomonads of the genus Paraphysomonas are ubiquitous phagotrophs with diverse silica scale morphology. Over 50 named species have been described by electron microscopy from uncultured environmental samples. Sequence data exist for very few, but the literature reveals misidentification or lumping of most previously sequenced. For critically integrating scale and sequence data, 59 clonal cultures were studied light microscopically, by sequencing 18S ribosomal DNA, and recording scale morphology by transmission electron microscopy. We found strong congruence between variations in scale morphology and rDNA sequences, and unexpectedly deep genetic diversity. We now restrict Paraphysomonas to species with nail-like spine scales, establishing 23 new species and eight subspecies (Paraphysomonadidae). Species having base-plates with dense margins form three distinct subclades; those with a simple margin only two. We move 29 former Paraphysomonas species with basket scales into a new genus, Clathromonas, and describe two new species. Clathromonas belongs to a very distinct rDNA clade (Clathromonadidae fam. n.), possibly distantly sister to Paraphysomonas. Molecular and morphological data are mutually reinforcing; both are needed for evaluating paraphysomonad diversity and confirm excessive past lumping. Former Paraphysomonas species with neither nail-like nor basket scales are here excluded from Paraphysomonas and will be assigned to new genera elsewhere.
副单鞭金藻属的异养金藻是普遍存在的吞噬营养生物，具有多样的硅质鳞片形态。通过电子显微镜，已从未培养的环境样本中描述了50多种命名物种。仅有极少数物种有序列数据，但文献显示大多数先前测序的物种存在错误鉴定或归类。为了严格整合鳞片和序列数据，我们对59个克隆培养物进行了光学显微镜研究，对18S核糖体DNA进行测序，并通过透射电子显微镜记录鳞片形态。我们发现鳞片形态变异与核糖体DNA序列之间有很强的一致性，以及意外的深度遗传多样性。我们现在将副单鞭金藻属限定为具有钉状棘状鳞片的物种，建立了23个新物种和8个亚种（副单鞭金藻科）。具有边缘密集基板的物种形成三个不同的亚分支；只有简单边缘的物种形成两个亚分支。我们将29个具有篮状鳞片的原副单鞭金藻属物种移入一个新属——笼形金藻属，并描述了两个新物种。笼形金藻属属于一个非常独特的核糖体DNA分支（新科笼形金藻科），可能是副单鞭金藻属的远亲姐妹。分子和形态数据相互印证；两者对于评估副单鞭金藻属的多样性和确认过去过度的归类都是必要的。既没有钉状鳞片也没有篮状鳞片的原副单鞭金藻属物种在此被排除在副单鞭金藻属之外，并将在其他地方归入新属。
