Morphological evolution of silica scales in the freshwater genus Synura (Stramenopiles)
Morphological evolution of silica scales in the freshwater genus Synura (Stramenopiles)
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DOI：
10.1111/jpy.13093
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发表时间：
2020-12-17
影响因子：
2.9
通讯作者：
Skaloud, Pavel
中科院分区：
文献类型：
--
作者：
Jadrna, Iva;Siver, Peter A.;Skaloud, Pavel
在金藻属SyNura的物种形成的华丽雕刻的硅质鳞片之间表现出高度的形态变异。在这项研究中，我们旨在揭示该属鳞片形态演变的一般原理和趋势。我们使用包括6个基因的稳健的分子分析，结合物种特有鳞片的形态特征，评估了30个现存的SyNura物种之间的关系。通过增加化石标本的形态信息，并包括独特的现代物种--点状针叶珊瑚，进一步丰富了分析。我们推测了形态上独特的斑点海鞘的系统发育地位，认为它是一个古老的SyNura谱系，与海鞘海鞘亚科中的海鞘海鞘有亲缘关系。一些形态特征，包括鳞片上龙骨或迷宫肋纹的发育，在进化过程中只出现过一次，而其他结构，如六角网纹，则在地质年代中独立起源了几次。我们进一步揭示了许多支配鳞片形态和演化的构造原理，如下：(I)鳞片圆度和孔径在进化过程中减少；(Ii)细长的鳞片因更多的支柱或肋骨而变得坚固；(Iii)由于鳞片的生物发生，带刺的鳞片的基孔比具有龙骨和龙骨的鳞片具有更小的基孔；(Iv)龙骨面积与鳞片面积成正比，表明其在加强鳞片抗断裂方面的潜在价值。
A high degree of morphological variability is expressed between the ornately sculptured siliceous scales formed by species in the chrysophycean genus, Synura. In this study, we aimed to uncover the general principles and trends underlying the evolution of scale morphology in this genus. We assessed the relationships among thirty extant Synura species using a robust molecular analysis that included six genes, coupled with morphological characterization of the species-specific scales. The analysis was further enriched with addition of morphological information from fossil specimens and by including the unique modern species, Synura punctulosa. We inferred the phylogenetic position of the morphologically unique S. punctulosa, to be an ancient Synura lineage related to S. splendida in the section Curtispinae. Some morphological traits, including development of a keel or a labyrinth ribbing pattern on the scale, appeared once in evolution, whereas other structures, such as a hexagonal meshwork pattern, originated independently several times over geologic time. We further uncovered numerous construction principles governing scale morphology and evolution, as follows: (i) scale roundness and pore diameter decreased during evolution; (ii) elongated scales became strengthened by a higher number of struts or ribs; (iii) as a consequence of scale biogenesis, scales with spines possessed smaller basal holes than scales with a keel and; and (iv) the keel area was proportional to scale area, indicating its potential value in strengthening the scale against breakage.