Evolution of the diatoms: insights from fossil, biological and molecular data
Evolution of the diatoms: insights from fossil, biological and molecular data
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DOI：
10.2216/05-22.1
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发表时间：
2006-07
期刊：
影响因子：
1.6
通讯作者：
P. Sims;D. Mann;L. Medlin
中科院分区：
文献类型：
--
作者：
P. Sims;D. Mann;L. Medlin
P.A. D.G.西姆斯Mann和L.K.麦德林2006.硅藻的进化：从化石、生物和分子数据中获得的见解。Phycologia 45：361-402。DOI：10.2216/05-22.1分子序列分析对硅藻的进化产生了许多重要的见解，但很少有人试图将这些与硅藻的大量化石记录联系起来，这可能是因为对现有数据不熟悉，这些数据广泛分散在地质文献中。我们回顾了分子生物学的主要特征，并集中在这些和化石记录之间的对应关系，我们还回顾了主要形态，细胞学和生命周期特征的演变，以及可能的硅藻起源。硅藻的第一个物理遗迹来自侏罗纪，保存完好的，多样的植物群来自早白垩世。虽然这些都是明确地确定为中心的硅藻，除了可能的Stephanopyxis可以明确地联系到现存的硅藻谱系，虽然它几乎可以肯定的是，Coscinodiscophyceae（径向中心）和Mediophyceae（极中心）的成员存在;一些显示奇怪的形态特征，暗示了一个非正统的细胞分裂机制和生命周期。最早的硅藻似乎最有可能是海洋的，但最近发现的化石沉积暗示陆地殖民可能发生在中生代，尽管淡水的主要入侵似乎被推迟到新生代。到了白垩纪晚期，许多谱系都与现存的硅藻类群有着令人信服的联系。羽纹硅藻出现在白垩纪晚期，而针纹硅藻出现在古新世，尽管分子系统发育表明针纹硅藻实际上进化得要早得多。最近的证据表明，硅藻是大大低于分类的物种水平，与许多半隐或隐物种被确认，但是，有很少的前景，能够区分这些类群的化石材料。
P.A. Sims, D.G. Mann and L.K. Medlin. 2006. Evolution of the diatoms: insights from fossil, biological and molecular data.Phycologia 45: 361–402. DOI: 10.2216/05-22.1 Molecular sequence analyses have yielded many important insights into diatom evolution, but there have been few attempts to relate these to the extensive fossil record of diatoms, probably because of unfamiliarity with the data available, which are scattered widely through the geological literature. We review the main features of molecular phylogenies and concentrate on the correspondence between these and the fossil record; we also review the evolution of major morphological, cytological and life cycle characteristics, and possible diatom origins. The first physical remains of diatoms are from the Jurassic, and well-preserved, diverse floras are available from the Lower Cretaceous. Though these are unequivocally identifiable as centric diatoms, none except a possible Stephanopyxis can be unequivocally linked to lineages of extant diatoms, although it is almost certain that members of the Coscinodiscophyceae (radial centrics) and Mediophyceae (polar centrics) were present; some display curious morphological features that hint at an unorthodox cell division mechanism and life cycle. It seems most likely that the earliest diatoms were marine, but recently discovered fossil deposits hint that episodes of terrestrial colonization may have occurred in the Mesozoic, though the main invasion of freshwaters appears to have been delayed until the Cenozoic. By the Upper Cretaceous, many lineages are present that can be convincingly related to extant diatom taxa. Pennate diatoms appear in the late Cretaceous and raphid diatoms in the Palaeocene, though molecular phylogenies imply that raphid diatoms did in fact evolve considerably earlier. Recent evidence shows that diatoms are substantially underclassified at the species level, with many semicryptic or cryptic species to be recognized; however, there is little prospect of being able to discriminate between such taxa in fossil material.