Department of Invertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia.
J Morphol. 2024 Mar;285(3):e21685. doi: 10.1002/jmor.21685.
The musculature is one of the best studied organ systems in brachiopods, being approachable not only by dissecting recent species of brachiopods, but also by exploring muscle scars in fossil material. In the present study, the muscular anatomy of Novocrania anomala is studied using 3D reconstructions based on microcomputed tomography. Muscles of N. anomala may be subdivided into two groups: those related to movements of the lophophore, and those connected to movements of shell valves. Muscles, their morphology and possible functions, such as brachial protractors, elevators, and retractors, as well as anterior adductors, are described and discussed. We also provide the discussion of craniid muscle terminology, consider the valve-opening mechanism. The investigation of muscle scars on dorsal valves supports the conclusion that the shape of muscle scars should be used for description and distinction of recent and extinct species only when visible distinctness cannot be explained by substrate differences. This study, which is aimed at improving our understanding the anatomy and functioning of muscles in craniids, will be useful not only for zoologists, but also for paleontologists.
肌系统是腕足动物中研究得最好的器官系统之一，不仅可以通过解剖现代腕足动物物种来研究，还可以通过研究化石中的肌肉痕迹来研究。在本研究中，使用基于微计算机断层扫描的 3D 重建来研究 Novocrania anomala 的肌肉解剖结构。N. anomala 的肌肉可分为两组：与腕足动物运动有关的肌肉，以及与壳瓣运动有关的肌肉。描述并讨论了肌肉、它们的形态和可能的功能，如臂伸展肌、提升肌和缩回肌，以及前收肌。我们还讨论了头足类肌肉术语，考虑了瓣开合机制。对背瓣上肌肉痕迹的研究支持这样的结论，即只有在无法用基底差异来解释明显可见性差异的情况下，才能使用肌肉痕迹的形状来描述和区分现生和已灭绝的物种。这项旨在提高我们对头足类动物肌肉解剖结构和功能的理解的研究，不仅对动物学家有用，对古生物学家也有用。
