Convergence and contingency in the evolution of a specialized mode of life: multiple origins and high disparity of rock-boring bivalves
Convergence and contingency in the evolution of a specialized mode of life: multiple origins and high disparity of rock-boring bivalves
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DOI：
10.1098/rspb.2022.1907
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发表时间：
2023-02-08
影响因子：
4.7
通讯作者：
Jablonski，David
中科院分区：
文献类型：
--
作者：
Collins，Katie S. S.;Edie，Stewart M. M.;Jablonski，David
进化适应新的，专门的生活模式往往与密切映射的形式，以新的功能，导致在狭窄的形态差异。对于双壳类软体动物，内石（钻岩）的生物力学要求被认为是强烈偏离祖先的功能。然而，双壳类的内石至少起源了八次。三维形态测量数据，约94%的现存的内石器时代的属和科，沿着与310个非内石器时代的物种在这些家庭中的75个物种，显示内石器是进化访问从许多不同的形态起点。虽然有些内石器似乎收敛于某些壳形态，内石器壳形式的范围是广泛的，属于任何其他双壳类基板使用。尽管如此，在今天的双壳纲中，内石器是一个分类贫乏的功能。这种有限的丰富性并不来自源分支内具有显着的低起源或高灭绝率的起源，今天的内石器并不局限于低多样性的地理区域。相反，内石器可能受到栖息地可用性的限制。决定论（反映在远亲类群之间的趋同）和偶然性（反映在保持接近其源分支的不同形态的内石器）都是内石器形态空间占据的基础。
Evolutionary adaptation to novel, specialized modes of life is often associated with a close mapping of form to the new function, resulting in narrow morphological disparity. For bivalve molluscs, endolithy (rock-boring) has biomechanical requirements thought to diverge strongly from those of ancestral functions. However, endolithy in bivalves has originated at least eight times. Three-dimensional morphometric data representing 75 species from approximately 94% of extant endolithic genera and families, along with 310 non-endolithic species in those families, show that endolithy is evolutionarily accessible from many different morphological starting points. Although some endoliths appear to converge on certain shell morphologies, the range of endolith shell form is as broad as that belonging to any other bivalve substrate use. Nevertheless, endolithy is a taxon-poor function in Bivalvia today. This limited richness does not derive from origination within source clades having significantly low origination or high extinction rates, and today's endoliths are not confined to low-diversity biogeographic regions. Instead, endolithy may be limited by habitat availability. Both determinism (as reflected by convergence among distantly related taxa) and contingency (as reflected by the endoliths that remain close to the disparate morphologies of their source clades) underlie the occupation of endolith morphospace.