目的 用形态学和分子生物学方法鉴定采自石家庄地区野生褐家鼠大肠的线虫种类。方法 采集河北省石家庄市藁城区野生褐家鼠大肠中的线虫，利用光学显微镜和扫描电子显微镜观察线虫的形态特征，确定线虫种类。取雌虫、雄虫各1条，提取虫体基因组DNA并扩增内转录间隔区1（ITS-1）序列和线粒体细胞色素c氧化酶Ⅰ亚基（cox1）基因，测序后用贝叶斯与最大似然法分别构建系统进化树。结果 共鉴定线虫35条，其中雄虫16条，雌虫19条。镜下可见，虫体细小呈圆柱形，两端渐细，表皮薄且具细微环纹，侧翼起始于咽部。头部具有3片发育良好的唇瓣，背唇具2个乳突，两个亚腹唇各有1个乳突，食管前端较细呈圆柱形，末端膨大呈球状。雄虫体长7.083~9.708 mm，具两条长度大致相同的交合刺，长0.250~0.310 mm，尾端具9对尾乳突。雌虫体长9.541~12.208 mm，阴门位于身体后部，周围具有3~5个褶皱，尾端细长具有一对乳突，肛门距尾端为0.916~1.083 mm，虫卵呈椭圆形，长和宽分别为0.050~0.058 mm、0.033~0.041 mm。测序结果显示，ITS-1序列长430 bp（GenBank登录号为PX622390），与达氏异刺线虫（GeneBank登录号为JX845277）的序列相似度为99.91%，与异刺属其他6个虫种的序列相似度为82.4%~90.3%；cox1序列长345 bp（GenBank登录号为PX622389），与异刺属其他7个虫种的序列相似度为82.0%~96.7%。异刺属cox1序列的系统进化树分析结果显示，本研究获得的线虫与鼠异刺线虫亲缘关系较近但相互独立，与异刺属其他物种亲缘关系较远。异刺属ITS-1序列的系统进化树分析结果显示，本研究获得的线虫与达氏异刺线虫亲缘关系最近，且与鼠异刺线虫聚为一支，与异刺属其他物种亲缘关系较远。结论 基于形态学特征鉴定、基因测序和系统进化分析结果，判断本研究获得的线虫为达氏异刺线虫，该物种为中国新纪录种。

Objective To characterize the nematode specimens collected from large intestines of wild Rattus norvegicus in Shijiazhuang City by means of morphological and molecular biological techniques assays. Methdos Nematodes were sampled from large intestines of wild R. norvegicus in Gaocheng District, Shijiazhuang City, Hubei Province, and the morphological characteristics of nematodes were examined using light and scanning electron microscop to identify the nematode species. A female worm and a male worm were sampled for extraction of genomic DNA, and internal transcribed spacer 1 (ITS-1) and mitochondrial cytochrome c oxidase subunit 1 (cox1) genes were amplified. Following sequencing of amplification products, phylogenetic trees were created using Bayesian inference and maximum likelihood methods. Results A total of 35 nematodes were identified, including 16 males and 19 females. The worms were small and cylindrical, tapered at both ends. The thin cuticles exhibited fine and transverse striations and lateral alae, with the latter originating from the pharyngeal region. The head featured three well-developed lips, including a dorsal lip with two papillae and two ventrolateral lips, each with one papilla. The anterior esophagus was narrow and cylindrical, expanding posteriorly into a bulb. The body length was 7.083 mm to 9.708 mm in males and 9.541 mm to 12.208 mm in females. Males were further characterized by two spicules of approximately equal length (0.250 mm to 0.310 mm) and nine pairs of caudal papillae. The vulva of female worms was situated in the posterior body region, surrounded by 3 to 5 cuticular folds. The tail terminated in a slender point adorned with a pair of terminal papillae and the distance from the anus to the tail tip measured 0.916 mm to 1.083 mm. The nematode eggs were elliptical in shape, with a length measuring 0.050 mm to 0.058 mm and a width measuring 0.033 mm to 0.041 mm. Sequencing revealed that the sequence of the ITS-1 gene was 430 bp in length (GenBank accession No. PX622390), and shared 99.91% similarity with Heterakis dahomensis (GenBank accession No. JX845277) and 82.4% to 90.3% similarity with other 6 Heterakis species. The sequence of the cox1 gene was 345 bp in length (GenBank accession No. PX622389), and shared 82.0% to 96.7% similarity with other 7 Heterakis species. Phylogenetic analysis based on the cox1 sequence of Heterakis revealed that nematode obtained from this study was closely related to H. spumosa but independent of each other, and was distantly related to other species of Heterakis. Phylogenetic analysis based on the ITS-1 gene sequence showed that the nematode sampled from this study was most closely related to H. dahomensis, and was clustered with Heterakis spumosa into a clade, but was distantly to other species of Heterakis. Conclusion Based on morphological characteristics, gene sequencing, and phylogenetic analysis, the nematode obtained from this study was identified as H. dahomensis, which is a newly recorded species in China.