Pseudo-cryptic speciation in coccolithophores
Pseudo-cryptic speciation in coccolithophores
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DOI：
10.1073/pnas.1132069100
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发表时间：
2003-06-10
影响因子：
11.1
通讯作者：
Medlin, LK
中科院分区：
文献类型：
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作者：
Sáez, AG;Probert, I;Medlin, LK
颗石藻是一类钙化的单细胞藻类，是海洋初级生产力的重要组成部分，在全球碳循环中发挥着重要作用，是重要的生物地层标志化石。它们的分类主要是基于覆盖在细胞上的微小方解石板或球石的形态。这些是不同的，包括广泛的精细尺度变化，其中生物学/分类学意义是未知的。它们是否代表表型可塑性、遗传多态性或物种特异性特征？我们对五种常见的颗石藻的研究支持这样的假设，即这种变化代表了pseudoscryptic物种形成事件，发生在0.3和12.9百万年前的分子钟估计。这一发现表明强烈的稳定选择作用于颗石藻表型。我们的研究结果也提供了强有力的支持，利用细尺度形态特征的球石化石记录，以提高生物地层分辨率和古海洋数据检索。
Coccolithophores are a group of calcifying unicellular algae that constitute a major fraction of oceanic primary productivity, play an important role in the global carbon cycle, and are key biostratigraphic marker fossils. Their taxonomy is primarily based on the morphology of the minute calcite plates, or coccoliths, covering the cell. These are diverse and include widespread fine scale variation, of which the biological/taxonomic significance is unknown. Do they represent phenotypic plasticity, genetic polymorphisms, or species-specific characters? Our research on five commonly occurring coccolithophores supports the hypothesis that such variation represents pseudocryptic speciation events, occurring between 0.3 and 12.9 million years ago from a molecular clock estimation. This finding suggests strong stabilizing selection acting on coccolithophorid phenotypes. Our results also provide strong support for the use of fine scale morphological characters of coccoliths in the fossil record to improve biostratigraphic resolution and paleoceanographic data retrieval.