Laboratory of Conservation and Utilization of Fish Resources, College of Life Sciences, Neijiang Normal University, Neijiang 641100, China. .
Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 04763, Korea.
Zootaxa. 2021 Oct 12;5051(1):529-549. doi: 10.11646/zootaxa.5051.1.21.
Two new species in the genus Nannopus Brady, 1880 (Copepoda: Harpacticoida) from intertidal mudflats of the Yellow Sea along the Korean peninsula, Nannopus cylindricus sp. nov. and N. robustus sp. nov., are described. Nannopus cylindricus belongs to the group of Nannopus species with seven elements on P4 exp-3. Within this group, it is closest to a cryptic species complex related to N. ganghwaensis Vakati, Kihara Lee, 2016 based on an inflated caudal seta IV. However, N. cylindricus differs from the other species in this complex with respect to caudal seta V (inflated and heavily cylindrical at its base in N. cylindricus, inflated only in the N. ganghwaensis cryptic complex). Nannopus robustus belongs to the group of species displaying two setae on P2 enp-2. Within this group, N. robustus is closely related to N. serratus Vakati Lee, 2017 based on the presence of one endopodal naked seta arising from a stem-like protrusion on the mandibular palp. However, N. robustus can be distinguished from N. serratus based on the following characters: outermost distal spine on P2 exp-3 (extremely strong, smooth and recurved in N. robustus, moderately strong, denticulate and normal-shaped in N. serratus, and spine 1.6 times as long in N. robustus as in N. serratus), P2 exp-2 inner seta (absent in N. robustus, present in N. serratus), shape of caudal seta V (anterior part distinctly cylindrical in N. robustus, normal-shaped in N. serratus), and ornamentation of caudal seta VI (naked in N. robustus, pinnate in N. serratus). An updated key to the 17 valid species of Nannopus is provided.
本文描述了黄海潮间带泥滩中新发现的两新种棒腕水蚤属（桡足亚目：哲水蚤目），即圆柱棒腕水蚤（Nannopus cylindricus）新种和粗壮棒腕水蚤（N. robustus）新种。圆柱棒腕水蚤属于 P4 exp-3 具 7 刚毛的棒腕水蚤种团，与基于膨胀的 IV 尾刚毛而相关的隐存种复合体关系最近，该复合体与 N. ganghwaensis Vakati，Kihara Lee，2016 相关。然而，圆柱棒腕水蚤与该隐存种复合体中的其他种不同，在于 V 尾刚毛（基部膨胀且呈圆柱形，在圆柱棒腕水蚤中，仅在 N. ganghwaensis 隐存种复合体中膨胀）。粗壮棒腕水蚤属于 P2 enp-2 具 2 刚毛的种团，与具颚须上一个由茎状突起生出的无刚毛的内附肢的 N. serratus Vakati Lee，2017 关系最近。然而，粗壮棒腕水蚤可与 N. serratus 相区别，基于 P2 exp-3 最外端远端刺（在粗壮棒腕水蚤中极度强壮、光滑且弯曲，在 N. serratus 中则是中度强壮、具小齿且正常形状，且在粗壮棒腕水蚤中比在 N. serratus 中长 1.6 倍）、P2 exp-2 内刚毛（在粗壮棒腕水蚤中缺失，在 N. serratus 中存在）、V 尾刚毛形状（在粗壮棒腕水蚤中前部分明显呈圆柱形，在 N. serratus 中正常形状）和 VI 尾刚毛的装饰（在粗壮棒腕水蚤中为裸露的，在 N. serratus 中为羽状的）。提供了一个 17 种有效棒腕水蚤属的修订检索表。
