Laboratory of Morphology (LAMAF), Institute of Biosciences, São Paulo State University (UNESP), Rio Claro, Brazil.
Laboratory of Metabolism and Reproduction of Aquatic Animals, Department of Physiology, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.
Microsc Res Tech. 2021 Sep;84(9):2017-2023. doi: 10.1002/jemt.23757. Epub 2021 Mar 18.
Shark skin is predominantly specialized for swimming and protection, with the dermal denticle being the main structure associated with these abilities. The dermal denticle is a mineral structure with a unique morphology for each species, which allows its use as a taxonomic tool. Few studies have investigated the microscopy aspects of skin and dermal denticles, considering the high diversity of sharks. Here, we investigated the three-dimensional morphoquantitative aspects and mineral composition of dermal denticles in different regions of the angular angel shark, Squatina guggenheim, using scanning electron microscopy and dispersive energy system. With the microscopy, we were able to observe that the dermal denticle morphology changes according to the area it is located. It was possible to describe the dermal denticles individually, from root to the crown, highlighting all of their individualities. Through the dispersive energy system, we showed the proportions of each mineral found in the denticle, by area, demonstrating the composition and the particularities of crown, body, and root, where whitlockite was described for the first time in elasmobranchs. In this way, the present study presented the specificities of the dermal denticles of S. guggenheim, as well sought to understand the different structure functions for the animal, thus assisting future research in animal morphology.
鲨鱼的皮肤主要用于游泳和保护，其真皮齿是与这些能力相关的主要结构。真皮齿是一种具有独特形态的矿物质结构，每种物种都有其独特的形态，这使其成为一种分类工具。很少有研究调查过皮肤和真皮齿的显微镜方面，考虑到鲨鱼的高度多样性。在这里，我们使用扫描电子显微镜和分散能系统研究了角鲨 Squatina guggenheim 不同部位的真皮齿的三维形态定量和矿物组成。通过显微镜，我们能够观察到真皮齿的形态根据其所在的区域而变化。我们能够单独描述真皮齿，从根部到冠部，突出它们的所有个性。通过分散能系统，我们按面积展示了在齿中发现的每种矿物质的比例，展示了冠、体和根的组成和特殊性，其中磷灰石首次在软骨鱼类中被描述。通过这种方式，本研究介绍了 S. guggenheim 的真皮齿的特异性，并试图了解动物的不同结构功能，从而为动物形态学的未来研究提供帮助。
