The parasites infecting invasive carps in North America (all Cypriniformes: Xenocyprididae: grass carp, Ctenopharyngodon idella [Valenciennes, 1844]; silver carp, Hypophthalmichthys molitrix [Valenciennes, 1844]; bighead carp, Hypophthalmichthys nobilis [Richardson, 1845]; and black carp, Mylopharyngodon piceus [Richardson, 1846]) are little studied, and no parasite has been reported from silver carp there. We herein surveyed silver carp from Barkley Reservoir and Cheatham Reservoir (Cumberland River, Tennessee; June and December 2021) and the White River (Arkansas; May 2022) and collected numerous monogenoid specimens infecting the pores on the outer face of the gill raker plate. We heat-killed, formalin-fixed, and routinely stained some specimens for morphology and preserved others in 95% ethanol for DNA extraction and sequencing of the large subunit ribosomal DNA (28S). We identified our specimens as Dactylogyrus cf. skrjabini because they had a dorsal anchor deep root that is much longer than the superficial root, an approximately parallel penis and accessory piece, and a relatively large marginal hook pair V. No type specimen of Dactylogyrus skrjabiniAkhmerov, 1954 (type host and locality is silver carp, Amur River, Russia) is publicly available, but we borrowed several vouchers (NSMT-Pl 6393) that infected the gill rakers of silver carp captured in the Watarase River, Japan. The original description of D. skrjabini was highly stylized and diagrammatical, differing from the specimens we studied from North America and Japan by the dorsal anchor having a superficial root and shaft that comprise a strongly C-shaped hook (the superficial root curves toward the dorsal anchor point) (vs. superficial root straight, at ∼45° angle to deep root and directed away from the dorsal anchor point), a single, much reduced transverse bar that is narrow for its entire breadth (vs. dorsal and ventral transverse bars robust and broad, having an irregular outline), an accessory piece that lacks digitiform projections (vs. accessory piece with 4 digitiform projections), and an accessory piece that lacks a half cardioid-shaped process (vs. accessory piece having a half cardioid-shaped process). Our 28S sequences (generated from 4 specimens of D. cf. skrjabini: 2 from Tennessee [763 base pairs (bp)] and 2 from Arkansas [776 bp]) were identical to 1 ascribed to D. skrjabini from Japan. The present study is the first verifiable and credible report of a parasite from silver carp in North America and the first nucleotide information for a parasite from silver carp in North America.

感染北美入侵鲤鱼的寄生虫（所有鲤形目：异鲤科：草鱼、Ctenopharyngodon idella [Valenciennes, 1844]；鲢鱼、Hypotropicmichthys molitrix [Valenciennes, 1844]；鳙鱼、Hypotropicmichthys nobilis [Richardson, 1845]；和青鱼, Mylopharyngodon piceus [Richardson, 1846]）的研究很少，并且没有关于那里的鲢鱼寄生虫的报道。我们在此调查了巴克利水库和奇塔姆水库（田纳西州坎伯兰河；2021 年 6 月和 12 月）和怀特河（阿肯色州；2022 年 5 月）的鲢鱼，并收集了许多感染鳃耙板外表面上的孔的单基因样本。我们对一些样本进行热灭活、福尔马林固定并常规染色以进行形态学观察，并将其他样本保存在 95% 乙醇中，用于 DNA 提取和大亚基核糖体 DNA (28S) 的测序。我们将我们的标本鉴定为Dactylogyrus cf. skrjabini，因为它们有一个比浅根长得多的背锚深根，一个近似平行的阴茎和附件，以及一个相对较大的边缘钩对 V。没有 Dactylogyrus skrjabini Akhmerov 的模式标本，1954 年（模式宿主和产地为俄罗斯阿穆尔河鲢鱼）是公开的，但我们借用了几张感染了日本渡良濑河捕获的鲢鱼鳃耙的凭证（NSMT-Pl 6393）。D. skrjabini的原始描述是高度程式化和图解化的，与我们从北美和日本研究的标本不同，背锚具有浅根和轴，包括一个强烈的 C 形钩（浅根向背侧弯曲）锚点）（与浅根直，与深根成~45°角并远离背侧锚点），单个、大大减少的横杆，其整个宽度较窄（与背侧和腹侧横杆相比）坚固而宽大，具有不规则的轮廓），缺少指状突起的附件件（与具有 4 个指状突起的附件件相比），以及缺少半心形突起的附件件（与具有半心形突起的附件件相比）成型工艺）。我们的28S序列（由 4 个D. skrjabini样本生成：2 个来自田纳西州 [763 个碱基对 (bp)]，2个来自阿肯色州 [776 bp]）与来自日本的 1 个D. skrjabini序列相同。本研究是北美鲢鱼寄生虫的第一份可验证和可信的报告，也是北美鲢鱼寄生虫的第一份核苷酸信息。