基于比较形态学的洞穴马陆适应特征研究

Cave millipedes are one of the most common and representative terrestrial cavernicolous animals in South China Karst. They are the best suitable species for studying morphological adaptations to subterranean life based on their very small distributions and high endemism. Our previous studies revealed that there are significant differences in the external morphology of troglobitic and epigean millipede species by the long-term cave life. In this project, we intend to continue the collection of troglobitic and epigean specimens in order to master the composition and distributions of millipedes; and analyze the phylogenetic relationship between troglobitic and epigean species for our investigated genera by means of DNA sequencing; as well as compare the external and internal structures between troglobitic and epigean millipede species by scanning electron microscopy and micro-CT scanning technology, so as to clarify their morphological adaptations to subterranean life of cavernicolous millipedes. The project will not only help to clarify composition of millipede diversity, but also provide important evidences to reveal the mechanism of adaptations in cavernicolous millipedes.

洞穴马陆是我国南方喀斯特洞穴中最常见和最具有代表性的陆生动物类群之一，其分布范围狭窄且特有性极高，是研究生物与洞穴环境相适应的最佳物种之一。申请者前期研究表明通过长期的洞穴生活，部分穴居与地表马陆代表性类群在外部形态存在显著的特征差异。本项目拟在传统分类学研究基础上，明确洞穴与地表马陆区系的构成和分布特点；并借助分子生物学方法对采集的标本进行系统发育分析，确定洞穴与地表马陆代表性类群种间的亲缘关系；进一步运用扫描电镜和micro-CT扫描对洞穴与地表马陆外部和内部结构进行比较分析，解析洞穴马陆对洞穴环境的形态适应特点。本项目开展的研究不仅有利于弄清我国马陆多样性的组成，同时还为揭示洞穴马陆对洞穴这一极端环境的适应进化机制提供新的理论依据。

马陆是一类古老、物种丰富且广泛分布的类群。全世界已记录约有16目150科3000属12000种，中国仅记载11目26科71属339种，其中1/3为洞穴种类。洞穴马陆是我国南方喀斯特洞穴生态系统中最有代表性的洞穴生物类群之一，在维持生态平衡中起着重要作用。本项目在广泛的样本采集基础上，初步摸清洞穴马陆的分类鉴定体系和完善地理分布数据，建立了中国马陆物种名录。结合形态学和DNA条形码对平带马陆属、雕背带马陆属、尼泡马陆属、刺圆马陆属等多个属的物种进行了分类学研究，包括物种的鉴定、描述、解剖、拍照等，共发表11个新种、1个新记录科，1个新纪录属，1个新记录种。此外，本项目通过对洞内和地表马陆的外部形态和内部结构比较形态学分析，基本明确了洞穴马陆在适应洞穴这一极端环境的形态特征变化。研究结果对马陆的生物多样性组成和洞穴动物对洞穴环境的形态适应进化上具有重要的科学意义。