Cambrian origin but no early burst in functional disparity for Class Bivalvia
Cambrian origin but no early burst in functional disparity for Class Bivalvia
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DOI：
10.1098/rsbl.2023.0157
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发表时间：
2023-05-31
期刊：
影响因子：
3.3
通讯作者：
Jablonski，David
中科院分区：
文献类型：
--
作者：
Zhou，Sharon;Edie，Stewart M.;Jablonski，David
超过 5 亿年前的寒武纪大爆发，以及大约 35 密尔之后的奥陶纪后果，通常被认为是广泛的生态机会的事件，但并非所有起源于这一时期的进化枝都表现出形态或功能差异的大量增加。在对功能差异的直接分析中，我们发现双壳纲的生态功能与分类多样化一致甚至滞后于分类多样化，而不是更常用的形态差异指标，而不是起源于所谓开放生态景观的进化枝所预期的早期爆发模式。与起源于寒武纪大爆发的其他几个分支不同，双壳类动物迟来获得关键的解剖学新奇事物造成了宏观进化的滞后，即使这些新奇事物在奥陶纪早期进化出来，功能差异也从未超过分类多样性。除了动物进化的早期阶段之外，新的主要进化枝及其功能的建立和随后的多样化可能会遵循早期双壳类的模式——其中高度动态的环境和生物景观以及进化偶然事件之间的相互作用不需要促进多产的功能创新。
Both the Cambrian explosion, more than half a billion years ago, and its Ordovician aftermath some 35 Myr later, are often framed as episodes of widespread ecological opportunity, but not all clades originating during this interval showed prolific rises in morphological or functional disparity. In a direct analysis of functional disparity, instead of the more commonly used proxy of morphological disparity, we find that ecological functions of Class Bivalvia arose concordantly with and even lagged behind taxonomic diversification, rather than the early-burst pattern expected for clades originating in supposedly open ecological landscapes. Unlike several other clades originating in the Cambrian explosion, the bivalves' belated acquisition of key anatomical novelties imposed a macroevolutionary lag, and even when those novelties evolved in the Early Ordovician, functional disparity never surpassed taxonomic diversity. Beyond this early period of animal evolution, the founding and subsequent diversification of new major clades and their functions might be expected to follow the pattern of the early bivalves—one where interactions between highly dynamic environmental and biotic landscapes and evolutionary contingencies need not promote prolific functional innovation.