Laboratório de Sistemática Zoológica, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, 18618-970, SP, Brazil.
Laboratório de Sistemática Zoológica, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, 18618-970, SP, Brazil; Museu de Zoologia, Universidade de São Paulo, São Paulo, 04263-000, SP, Brazil.
Arthropod Struct Dev. 2022 Jan;66:101132. doi: 10.1016/j.asd.2021.101132. Epub 2021 Dec 1.
Several majoid crabs are known to adhere exogenous materials to their bodies, a behaviour called decoration. Until now, the adhesion of exogenous materials to the body is most attributed to the well-known hooked setae. Here, we analysed the carapace of Macrocoeloma trispinosum (Latreille, 1825) under light and electron microscopy to study the different mechanisms allowing majoid crabs to decorate themselves. Five setal types are described here, of which four for the first time: velvet type I, velvet type II, depressa and cattail seta. These setae are morphologically and histologically detailed, and new hypotheses about the fixation of exogenous material on the carapace are explored. M. trispinosum has a complex setal apparatus for the adhesion of the decoration, with tegumental ducts along the shaft of most setae. These tegumental ducts are connected to glands formed by large cells arranged radially (rosette or acini) at the base of the setae, in the connective tissue, just below the epithelium. We could observe these glands in different stages of maturation, and no valve-like structure was observed, which may indicate a continuous flow of protein secretion that could serve as an adhesive substance found in the apex of most setae. This is the first record indicating a potential chemical adhesion mechanism aiding the masking process in decorator crabs.
已知几种扇蟹科螃蟹会将外生物黏附在身上，这种行为被称为装饰。到目前为止，外生物与身体的黏附最常归因于著名的钩状刚毛。在这里，我们通过光学显微镜和电子显微镜分析了三棘馒头蟹（Macrocoeloma trispinosum）的甲壳，以研究允许扇蟹科螃蟹进行自我装饰的不同机制。在这里描述了五种刚毛类型，其中四种是首次描述：绒毛型 I、绒毛型 II、压平刚毛和香蒲刚毛。这些刚毛在形态和组织学上都有详细描述，并对甲壳上外源物质固定的新假设进行了探讨。M. trispinosum 具有用于装饰固定的复杂刚毛装置，大多数刚毛的轴上都有表皮管。这些表皮管与由排列成放射状的大细胞形成的腺体相连（玫瑰或腺泡），位于刚毛的基部，在结缔组织中，就在上皮组织下方。我们可以观察到这些腺体处于不同的成熟阶段，而且没有观察到瓣膜状结构，这可能表明蛋白质分泌的连续流动，这种分泌物质可能是大多数刚毛顶端发现的粘性物质。这是第一个表明潜在化学黏附机制有助于装饰蟹伪装过程的记录。
