The central nervous system of velvet worms (Onychophora) - Shedding light on the evolution of the panarthropod brain

绒虫（Onychophora）的中枢神经系统——揭示泛节肢动物大脑的进化

• 批准号: 408490506
• 负责人: Professor Dr. Georg Mayer
• 金额: --
• 依托单位: Fachgebiet Zoologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/408490506?language=en
• 关键词: central; nervous; system; velvet; worms

Arthropods, arguably the most successful animals worldwide, have fascinated researchers for centuries due to the complexity of their bodies. One of the most important features of the arthropod body is their nervous system, which reflects the anatomical complexity to a great extent. Understanding the evolution of these puzzling organs requires investigations of both arthropods themselves and their closest relatives - Onychophora (velvet worms) and Tardigrada (water bears), which all together compose the Panarthropoda. As sister group to either tardigrades plus arthropods or arthropods alone, onychophorans play a key role for understanding the evolution of morphological traits within panarthropods. Nevertheless, despite their significant phylogenetic position, their nervous system, in particular the brain, is largely understudied. Therefore, the aims of the proposed project are to (i) clarify existing controversies surrounding the nomenclature and presumptions of putative homologies of the onychophoran brain to that of arthropods, and (ii) characterise numerous undescribed structures and features of the onychophoran brain. On the basis of 3D reconstructions of synchrotron radiation-based X-ray micro-computed tomographic and nanofocus X-ray source tomographic data sets - in addition to a wide range of neuroanatomical methods, such as a variety of antibody labelling and neuronal tracing - a three-dimensional "atlas" of the onychophoran brain will be designed. Moreover, this study will illuminate the onychophoran brain beyond morphological characters and, in addition, investigate potential neurogenesis in adult onychophorans, a feature so far unknown for these animals. Furthermore, the development of distinct brain regions will be examined as this will yield invaluable evidence for the origin of cerebral structures and, therefore, will help to draw putative homologies to arthropods. The obtained data will be valuable not only for understanding the anatomy of the onychophoran brain itself but, in addition, for elucidating the evolution of the anterior part of the central nervous system in panarthropods. The obtained results will therefore largely contribute to our understanding of the evolution of the intriguing arthropod nervous systems.

节肢动物可以说是世界上最成功的动物，由于它们身体的复杂性，几个世纪以来一直吸引着研究人员。节肢动物身体最重要的特征之一是神经系统，这在很大程度上反映了节肢动物解剖的复杂性。要想了解这些令人费解的器官的进化，需要对节肢动物本身及其最近的近亲--天鹅绒蠕虫和水熊--进行研究，它们共同构成了泛节肢动物。作为迟滞动物+节肢动物或单独与节肢动物的姊妹类，甲节动物在了解节肢动物形态特征的进化中起着关键作用。然而，尽管它们具有重要的系统发育地位，但它们的神经系统，特别是大脑，在很大程度上还没有得到充分的研究。因此，拟议项目的目的是(I)澄清围绕指甲脑的命名和推定与节肢动物脑同源的现有争议，以及(Ii)描述指甲脑的许多未描述的结构和特征。在对基于同步辐射的X射线微型计算机断层扫描和纳焦X射线源断层扫描数据集进行3D重建的基础上--除了各种神经解剖学方法，如各种抗体标记和神经元追踪--将设计一幅甲爪脑的三维“图谱”。此外，这项研究将阐明甲鱼的大脑不仅具有形态特征，而且还将研究成年甲鱼潜在的神经发生，这是这些动物迄今尚不了解的特征。此外，还将研究不同大脑区域的发育情况，因为这将为大脑结构的起源提供宝贵的证据，因此将有助于得出节肢动物的假定同源性。所获得的数据不仅对于了解甲节动物脑的解剖结构本身，而且对于阐明节肢动物中枢神经系统前部的进化都是有价值的。因此，所获得的结果将在很大程度上有助于我们理解有趣的节肢动物神经系统的进化。