Phylogenetic constraint and phenotypic plasticity in the shell microstructure of vent and seep pectinodontid limpets
Phylogenetic constraint and phenotypic plasticity in the shell microstructure of vent and seep pectinodontid limpets
复制标题
通风口和渗流果胶齿动物帽贝壳微结构的系统发育约束和表型可塑性
DOI：
10.1007/s00227-020-03692-z
复制
发表时间：
2020
期刊：
影响因子：
2.4
通讯作者：
Chen Chong
中科院分区：
文献类型：
--
作者：
Sato Kei;Watanabe Hiromi Kayama;Jenkins Robert G.;Chen Chong
Pectinodontid帽贝属Bathyacmaea特有的热喷口和冷泉，并表现出很大的变化壳和齿舌宏观形态，使可靠的物种水平的鉴定具有挑战性。在这里，我们分析了壳微结构的西太平洋喷口/seepBathyacmaealimpets使用扫描电子显微镜和拉曼分光光度法来测试其有用性，在提供系统发育signals.Bathyacmaeashells包括两种形式的方解石微结构，包括不规则的球晶棱柱A型（ISP A型）和半叶状（SF），以及文石交叉片层（CL）的微结构。尽管在宏观壳形态上存在显著差异，一度导致它们被划分为不同的种甚至属，但来自不同化能合成地点和底物的6种形态型的Bathyacmaea nipponica在其外壳层和内壳层中共享最外ISP-A层和SF和CL结构的交替层。然而，从南查莫罗海山发现的一个遗传上不同的谱系的不同之处在于，它有一个简单的三层壳组成，从外部依次由ISP-A、SF和CL结构组成，而一个非常薄的内壳层只由CL结构组成。此外，文石和方解石的比例因生境条件而异，方解石占主导地位的喷口和文石占主导地位的渗漏。这些结果表明，壳的微观结构的pectinodontids系统发育的限制，并提供了有用的分类信号，而文石/方解石比例的矿物多态性根据环境因素而变化。此外，来自白垩纪渗漏的两个“物种”的显微结构证实了化石谱系中的相同模式。
Pectinodontid limpets of the genusBathyacmaeaare endemic to hot vents and cold seeps and exhibit greatly variable shell and radular macro-morphologies, rendering reliable species-level identification challenging. Here, we analyzed shell microstructures of western Pacific vent/seepBathyacmaealimpets using scanning electron microscopy and Raman spectrophotometry to test its usefulness in providing phylogenetic signals.Bathyacmaeashells comprised of two forms of calcitic microstructure including irregular spherulitic prismatic type-A (ISP type-A) and semi-foliated (SF), as well as the aragonitic crossed lamellar (CL) microstructure. Despite marked differences in macroscopic shell morphologies once leading them to be classified into different species or even genera, six morphotypes ofBathyacmaea nipponicafrom different chemosynthetic localities and substrates shared an outermost ISP-A layer and alternating layers of SF and CL structures in their outer and inner shell layers. A genetically divergent lineage recovered from the South Chamorro Seamount, however, differed in having a simple three-layered shell composition consisting of ISP-A, SF, and CL structures, in that order, from the outside, and an unusually thin inner shell layer consisting of only CL structure. Moreover, the ratio of aragonite and calcite varied with habitat conditions, with calcite dominating in vents and aragonite dominating in seeps. These results suggest that the shell microstructure of pectinodontids is under phylogenetic constraints and provides useful taxonomic signals, while the mineral polymorphism in aragonite/calcite ratio varies according to environmental factors. Furthermore, microstructures of two ‘species’ from Cretaceous seeps confirmed the same patterns in fossil lineages.