九龙江口伪镖水蚤科一新种——沈氏伪镖水蚤

记述了采自九龙江口桡足类1个新种——沈氏伪镖水蚤（Pseudodiaptomus sheni Guo&Wang，sp.nov.），对其形态特征进行了拍照、绘图和描述。形态上，新种头部钝尖，雌性胸部后侧角内缘乳状突起明显、生殖厣末端突起呈长倒刺状、尾叉外侧第2和第3尾刚毛基部膨大、第5胸足外肢第1节内末角突起尖细，雄性第5胸足左足第2基节后缘中部三角形突起狭尖，与火腿伪镖水蚤P.poplesia（Shen，1955）]存在显著的形态差异；两者基于线粒体细胞色素氧化酶亚基Ⅰ（mtCOI）基因片段的遗传差异为17.4%~19.5%。沈氏伪镖水蚤的命名旨在纪念中国科学院动物研究所甲壳动物分类学家沈嘉瑞（1902-1975）研究员，模式标本保存于厦门大学海洋科技博物馆。

Pseudodiaptomus sheni sp. nov., one new species of Pseudodiaptomidae from the Jiulong River Estuary, Fujian

The samples of copepods were collected from the estuary of Jiulong River during September 2013 to September 2017. One new species of Pseudodiaptomidae, Pseudodiaptomus sheni Guo & Wang, sp. nov., which had been identified as the saccupodus type of P. poplesia (Shen, 1955) by Chen and Zhang (1965) and Shen (1979), is described. The differences between this new species and P. poplesia are as follows:(1) cephalosome rounded anteriorly, while that of P. poplesia narrowly protruded in dorsal view; (2) female posterolateral corner with distinct bump postermedially; (3) the posterior process of female genital operculum pointed and longer than that of P. poplesia; (4) the outer terminal 2nd and 3rd setae basally swollen on female caudal rami; (5) the first exopod segment of female fifth leg with distomedial acute projection, while that of P. poplesia with blunt one; 6) medial triangular projection on the endopod of male left fifth leg elongated and longer than that of P. poplesia. The mitochondrial cytochrome oxidase subunit Ⅰ (mtCOI) gene sequences support the conclusion based on morphological data, with distinct divergence values 17.4% to 19.5% between P. sheni and P. poplesia. The new species is named in honor of Prof. Chia-jui Shen (1902-1975), a senior crustacean taxonomist of Institute of Zoology, Chinese Academy of Sciences. All type specimens are deposited in Museum of Marine Science and Technology, Xiamen University.