Taxonomic descriptions and evolutionary implications of Middle Eocene pennate diatoms representing the extant generaOxyneis,ActinellaandNupela(Bacillariophyceae)
Taxonomic descriptions and evolutionary implications of Middle Eocene pennate diatoms representing the extant generaOxyneis,ActinellaandNupela(Bacillariophyceae)
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DOI：
10.5091/plecevo.2010.419
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发表时间：
2010-11
影响因子：
1.1
通讯作者：
P. Siver
中科院分区：
文献类型：
--
作者：
P. Siver
Actinella F.W.Lewis，Oxyneis圆形和Nupela Vyverman&Compère是已知的三个属的羽状硅藻，仅见于以稀释和酸性为主的淡水环境(Ciral.1990年，Sabbe等人。2001年，Siver等人。2007)。在这三个属中，Oxyneis是最小的属，只有三个种(Cird等人)。1990年，Metzeltin&Lange-Bertalot 2007)，尽管在该属内只有两个被正式描述。Oxyneis是一种蛛形目分类群，每个瓣膜有一个脊孔器和大量的腰带，每个腰带都有隔膜(圆形等人)。1990年，金斯敦2003年)。在这一点上，Oxyneis与Tabellaria Ehrenb关系密切。Ex Kütz.，一种常见的蛛形目淡水硅藻。Actinella和Nupela都具有中缝，尽管这一特征的形态非常不同，导致这两个属被放入不同的亚纲(圆形等人)。1990年)。Actinella的特征是中缝裂隙减少，每个瓣膜一个轮缘孔状体，以及沿所有三个轴不对称的小伞形花柱。Nupela在一个(异瓣型)或两个(等瓣型)瓣膜和对称的锥体上具有完全形成的中缝。虽然Nupela是由Vyverman&Compère于1991年建立的，但该属现在包含的大多数种最初被描述为Navrula，该属近年来已被分成许多分类群(见Metzeltin&Lange-Bertalot 1998,2007及其参考文献)。基于基因序列的系统发育研究
Actinella F.W.Lewis, Oxyneis Round and Nupela Vyverman & Compère are three genera of pennate diatoms known exclusively from freshwater environments that are predominantly dilute and acidic (Round et al. 1990, Sabbe et al. 2001, Siver et al. 2007). Of the three, Oxyneis is the smallest genus and comprises only three species (Round et al. 1990, Metzeltin & Lange-Bertalot 2007), although only two have formally been described within the genus. Oxyneis is an araphid taxon, possessing one rimoportula per valve and a large number of girdle bands, each equipped with a septum (Round et al. 1990, Kingston 2003). In this regard, Oxyneis is closely related to Tabellaria Ehrenb. ex Kütz., a common araphid freshwater diatom. Actinella and Nupela both possess a raphe, although the morphology of this feature is very different, yielding placement of the two genera into separate subclasses (Round et al. 1990). Actinella is characterized by reduced raphe slits, one rimoportula per valve, and frustules that are asymmetric along all three axes. Nupela has a fully formed raphe on one (heterovalvar forms) or both (isovalvar forms) valves and symmetric frustules. Although Nupela was established by Vyverman & Compère in 1991, the majority of species now contained within the genus were originally described as Navicula, a genus that has been split into numerous taxa in recent years (see Metzeltin & Lange-Bertalot 1998, 2007 and references therein). Phylogenies based on gene sequences