Laboratory of Functional and Evolutionary Morphology, FOCUS Research Unit, Department of Biology, Ecology and Evolution, University of Liège, Liège, Belgium.
Laboratory of Functional and Evolutionary Morphology, FOCUS Research Unit, Department of Biology, Ecology and Evolution, University of Liège, Liège, Belgium; Center for Applied Research and Education in Microscopy (CAREM), University of Liège, Liège, Belgium.
J Struct Biol. 2021 Dec;213(4):107810. doi: 10.1016/j.jsb.2021.107810. Epub 2021 Nov 11.
Stomatopoda is a crustacean order including sophisticated predators called spearing and smashing mantis shrimps that are separated from the well-studied Eumalacotraca since the Devonian. The spearing mantis shrimp has developed a spiky dactyl capable of impaling fishes or crustaceans in a fraction of second. In this high velocity hunting technique, the spikes undergo an intense mechanical constraint to which their exoskeleton (or cuticle) has to be adapted. To better understand the spike cuticle internal architecture and composition, electron microscopy, X-ray microanalysis and Raman spectroscopy were used on the spikes of 7 individuals (collected in French Polynesia and Indonesia), but also on parts of the body cuticle that have less mechanical stress to bear. In the body cuticle, several specificities linked to the group were found, allowing to determine the basic structure from which the spike cuticle has evolved. Results also highlighted that the body cuticle of mantis shrimps could be a model close to the ancestral arthropod cuticle by the aspect of its biological layers (epi- and procuticle including exo- and endocuticle) as well as by the Ca-carbonate/phosphate mineral content of these layers. In contrast, the spike cuticle exhibits a deeply modified organization in four functional regions overprinted on the biological layers. Each of them has specific fibre arrangement or mineral content (fluorapatite, ACP or phosphate-rich Ca-carbonate) and is thought to assume specific mechanical roles, conferring appropriate properties on the entire spike. These results agree with an evolution of smashing mantis shrimps from primitive stabbing/spearing shrimps, and thus also allowed a better understanding of the structural modifications described in previous studies on the dactyl club of smashing mantis shrimps.
十足目是一种甲壳动物，包括被称为矛虾和粉碎虾的复杂捕食者，它们自泥盆纪以来就与研究充分的真软甲亚纲分开了。矛虾已经进化出了一个多刺的尾节，能够在一瞬间刺穿鱼类或甲壳类动物。在这种高速捕食技术中，刺承受着强烈的机械约束，其外骨骼（或角质层）必须适应这种约束。为了更好地了解刺的角质层内部结构和组成，对 7 只个体（在法属波利尼西亚和印度尼西亚收集）的刺以及承受较小机械压力的身体角质层部分进行了电子显微镜、X 射线微分析和拉曼光谱分析。在身体角质层中，发现了几个与该组相关的特异性，这些特异性允许确定从刺角质层进化而来的基本结构。结果还表明，通过生物层（包括外角质层和内角质层的表皮和原角质层）以及这些层的 Ca-碳酸盐/磷酸盐矿物含量，虾蛄的身体角质层可能是接近祖先节肢动物角质层的模型。相比之下，刺角质层在生物层上覆盖了四个功能区域，表现出深度修改的组织。它们中的每一个都具有特定的纤维排列或矿物含量（氟磷灰石、ACP 或富含磷酸盐的 Ca-碳酸盐），并且被认为具有特定的机械作用，赋予整个刺适当的特性。这些结果与粉碎虾蛄从原始的刺虾蛄进化而来的观点一致，因此也有助于更好地理解以前关于粉碎虾蛄的指节棒的结构修饰的研究中描述的结构修饰。
