Neopsilotrema is a small genus of psilostomid digeneans parasitic in the intestine of birds in the Palearctic and Nearctic. At present, the genus includes 4 species: Neopsilotrema lisitsynae from the Palearctic and Neopsilotrema affine, Neopsilotrema lakotae, and Neopsilotrema marilae from the Nearctic. Herein, we describe a new species, Neopsilotrema itascae n. sp., from lesser scaup Aythya affinis collected in Minnesota. The species can be distinguished from congeners on the basis of the ventral sucker:oral sucker width ratio, body width:length ratio, and cirrus sac size, along with other characters. We generated new 28S ribosomal deoxyribonucleic acid (DNA) and NADH dehydrogenase (ND1) mitochondrial DNA sequence data of a variety of psilostomids from the Palearctic and Nearctic along with sequences of the ribosomal internal transcribed spacer (ITS) region (ITS1 + 5.8S + ITS2) from 3 Neopsilotrema species. The molecular phylogenetic affinities of a variety of psilostomid taxa were studied using 28S sequence data. The 28S sequences of psilostomids demonstrated 1–7.9% intergeneric divergence, whereas the sequences of ND1 had 17.7–34.1% intergeneric divergence. The interspecific divergence among members of Neopsilotrema was somewhat lower (0.2–0.5% in 28S; 0.3–0.4% in ITS; 12–15.7% in ND1). Our comparison of DNA sequences along with morphologic study suggests Holarctic distribution of N. lisitsynae.

Neopsilotrema是一种小属，寄生在古北和近北鸟类的肠道中。目前，该属包括4个种：来自古北界的Nepsilotrema lisitsynae和来自近北界的Nepsilotrema affine、Nepsilotrema lakotae和来自近北界的Nepsilotrema marilae 。在此，我们描述了一个新物种Neopsilotrema itascae n。sp.，来自在明尼苏达州收集的较小的 scaup Aythya affinis 。可以根据腹侧吸盘与口吸盘的宽度比、体宽与长度比、卷囊大小等特征来区分该物种与同类。我们生成了新的28S核糖体脱氧核糖核酸 (DNA) 和 NADH 脱氢酶 ( ND1 ) 线粒体 DNA 序列数据 来自古北和近北的各种 psilostomids 以及来自 3 Neopsilotrema的核糖体内部转录间隔区 ( ITS ) 区域 ( ITS1 + 5.8S + ITS2 ) 的序列物种。使用28S序列数据研究了各种 psilostomid 类群的分子系统发育亲和力。psilostomids的28S序列表现出 1-7.9% 的属间差异，而ND1的序列具有 17.7-34.1% 的属间差异。成员之间的种间差异Neopsilotrema稍低（28S为 0.2-0.5%； ITS为0.3-0.4% ； ND1为 12-15.7% ）。我们对 DNA 序列的比较以及形态学研究表明N. lisitsynae的全北极分布。