蛔总科线虫是人和动物体内重要的寄生虫类群，可对人类及动物健康和社会经济带来严重危害。然而，目前我国蛔总科线虫分类学研究还很薄弱，本底资源尚不清楚，蛔总科分类系统也存在较大争议，一些科、亚科、属的系统地位仍未解决，一些形态特征在不同属级阶元的分类学价值尚不明晰。本项目以经典分类学方法为主，辅以DNA分类手段对我国一些陆生脊椎动物和淡水鱼类寄生的蛔总科线虫进行分类修订。在此基础上，基于形态与分子数据，利用分支系统学与分子系统学手段，构建蛔总科代表类群的系统发育关系，检验当前蛔总科分类系统的合理性，重点解决棘唇科、哥泽亚科、伪尖亚科以及鱼蛔属、莫蛔属、肋蛔属等类群的系统地位的问题，同时探讨蛔总科常用的一些分类特征的演化规律，评估其在不同属级阶元中的分类学价值，进一步澄清阔肠属、蛇蛔属、葱肠属等类群的界定问题，为重建符合自然进化规律的蛔总科分类系统提供重要的理论依据。

Nematodes of the superfamily Ascaridoidea are important parasites of the alimentary tract of vertebrates and many species are potential causative agents of disease in humans, domesticated animals, and wildlife. However, our present knowledge of the composition of the ascaridoid nematode fauna in China is far from complete. The classification of Ascaridoidea was erected mainly on the basis of conventional taxonomy and we have not found a phylogenetic study of the whole superfamily Ascaridoidea that includes representatives of the worldwide fauna. This situation had a direct influence on the systematics of Ascaridoidea: the monophyly of some included family or subfamily-level taxa was challenging and the systematic position of Acanthocheilidae, Raphidascarididae, Goeziinae, Pseudanisakinae and their included genus-level taxa, for instance, Acanthocheilus, Ichthyascaris, Mawsonascaris, Maricostula, Goezia, Pseudanisakis had not been definitely solved for lacking reasonable phylogenetic analyses. The taxonomic definitions of some genera were thus questionable because of the uncertain taxonomic importance in defining different level taxa. In the present project, we will revise the taxonomy of Ascaridoidea in China mainly based on the traditional morphological methods. In addition, the phylogenetic analyses of Ascaridoidea based on morphological characters and molecular data including the ribosomal 18S, ITS and 28S genes and the mitochondrial 12S gene and COI, respectively, will be performed. The objectives of our phylogenetic study are three-fold: 1) to test the monophyly of the superfamily Ascaridoidea and some of its family or subfamily-level taxa. 2) to unravel the evolutionary relationships of Acanthocheilidae, Raphidascarididae, Goeziinae, Pseudanisakinae and their included genus-level taxa, with emphasis on the genera Acanthocheilus, Ichthyascaris, Mawsonascaris, Maricostula, Goezia, Pseudanisakis and their close-allied relatives. 3) to conjecture the evolutionary history of several morphological characters and evaluate the taxonomic importance of them in defining different level taxa. The results may provide important information for reconstructing the classification of the whole superfamily Ascaridoidea.