目的 鉴定黑龙江扎龙自然保护区丹顶鹤体内分离的吸虫，并以核糖体内转录间隔区（ITS）和28S序列为标记基因分析该吸虫的亲缘关系。方法 自黑龙江扎龙自然保护区自然死亡的丹顶鹤肠道内分离吸虫，使用盐酸卡红进行染色，观察虫体形态学特征。提取虫体DNA，PCR扩增ITS和28S序列，测序后进行序列分析、相似性分析和重复序列分析，以最大简约法构建系统进化树。结果 分离的吸虫具有虫体肥大、头领发达、头领呈二侧叶状等特征。该吸虫ITS序列长1 007 bp，其中ITS1、5.8S、ITS2的长度分别为389、161、457 bp；ITS序列G + C含量为52.14%。28S序列长983 bp，G + C含量为56.79%。ITS2序列有2个11 bp正向重复序列，28S无重复序列。本研究分离的吸虫ITS和28S序列与二叶冠缝吸虫（GenBank：ON141931，KT956945）的序列相似性为分别为94.39%和98.27%，与冠缝属吸虫处于同一小分支，鉴定为二叶冠缝吸虫。结论 黑龙江扎龙自然保护区丹顶鹤体内分离的吸虫为二叶冠缝吸虫。

Objective To characterize the trematode species isolated from Grus japonensis in the Heilongjiang Zhalong Nature Reserve, and to analyze the phylogenetic relationships of the trematode using ribosomal internal transcribed spacer (ITS) and 28S DNA sequences as molecular markers. Methods Trematodes were isolated from intestines of naturally deceased G. japonensis in the Heilongjiang Zhalong Nature Reserve and stained with hydrochloric acid-carmine to observe the morphological characteristics of trematodes. DNA was extracted from trematodes, and ITS and 28S sequences were amplified using PCR assay. PCR amplification products were sequenced, followed by sequence analysis, similarity analysis and repetitive sequence analysis. In addition, phylogenetic trees were built using the maximum parsimony method. Results The isolated trematodes had enlarged bodies, and well-developed, distinctly bilobed head collars. The length of the ITS sequence was 1 007 bp, and the lengths of ITS1, 5.8S and ITS2 sequences were 389, 161 and 457 bp, respectively. The G + C content of the ITS sequence was 52.14%. The length of 28S sequence was 983 bp and the G + C content was 56.79%. The ITS2 sequence had 2 forward repeat sequences with 11 bp in length and the 28S sequence had no repeat sequences. The ITS and 28S sequences of isolated trematodes shared 94.39% and 98.27% sequence similarities with those of P. bilobus (GenBank accession numbers: ON141931 and KT956945), and clustered into the same sub-clade with Patagifer species. The isolated trematodes were therefore identified as P. bilobus. Conclusion The trematodes isolated from G. japonensis in the Heilongjiang Zhalong Nature Reserve are P. bilobus.