Programa de Pós-Graduação em Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
Faculdade de Ciências Biológicas e Saúde, Universidade do Estado do Rio de Janeiro, Campus Zona Oeste, Av. Manuel Caldeira de Alvarenga, 1203, Campo Grande, Rio de Janeiro, RJ, 23070-200, Brazil.
Syst Parasitol. 2024 Apr 3;101(3):27. doi: 10.1007/s11230-024-10151-6.
The original description of Hatschekia exigua Pearse, 1951 neglected innumerous features of taxonomic value as well as morphometric data and illustrations. Posteriorly, other author tried to access the type material, but their poor state of preservation compromised a detailed redescription. Since then, this species is in need for new morphological data, mainly from fresh material. In the present work, three specimens of Holocentrus adscensionis from Mucuripe Bay, Fortaleza, State of Ceará, Northeastern Brazil, were parasitized by copepods on their gills. Parasites were fixed and preserved in 80% ethanol and cleared in 85% lactic acid for morphological observations using light microscopy. The females were identified as Hatschekia exigua by the cephalothorax representing about one-fourth of total body length, with lateral margins expanded into lateral lobes, first exopod with basal segment armed with one outer setae and terminal segment with three setae, first endopod with basal segment unarmed and terminal segment with five setae, leg 3 reduced to two setae and leg 4 reduced to single seta. Comparison with the type series revealed morphological differences in trunk and small appendages, which may be related to alterations in the specimens, caused by the mounting methodology and poor preservation. A detailed morphological analysis of the male revealed for the first time that they differ from their closest congeners by having five setae on the last endopodal segment of leg 1, by smooth intercoxal sclerites on legs 1 and 2 and by a proximolateral process on the third segment of antenna. Moreover, this work represents the first report of H. exigua in Brazil and the first hatschekiid copepod found off the coast of Ceará, highlighting that the diversity of Hatschekiidae in this oceanographic region still needs further investigation.
1951 年，Pearse 最初对 Hatschekia exigua 的描述忽略了许多具有分类价值的特征以及形态测量数据和插图。后来，其他作者试图查阅模式标本，但由于保存状况不佳，无法进行详细的重新描述。从那时起，该物种就需要新的形态学数据，主要来自新鲜材料。在本研究中，来自巴西塞阿拉州福塔莱萨市穆库里皮湾的 3 条 Holocentrus adscensionis 标本的鳃上寄生了桡足类寄生虫。寄生虫被固定并保存在 80%乙醇中，在 85%乳酸中澄清，以便使用光学显微镜进行形态观察。雌性寄生虫通过占身体总长度四分之一的头胸甲被鉴定为 Hatschekia exigua，其侧缘扩展成侧叶，第一外肢具基节具一根外生刚毛，末端具三根刚毛，第一内肢具基节无武装，末端具五根刚毛，腿 3 简化为两根刚毛，腿 4 简化为单根刚毛。与模式系列的比较显示，躯干和小附肢的形态存在差异，这可能与标本的变化有关，这些变化是由装裱方法和保存状况不佳引起的。对雄性的详细形态分析首次表明，它们与最接近的近缘种的区别在于腿 1 的最后内肢具 5 根刚毛，腿 1 和 2 的股间骨节光滑以及触角第三节的近侧前突。此外，这是首次在巴西报道 H. exigua，也是首次在塞阿拉州海岸外发现的 Hatschekiidae 桡足类，这表明该海洋区域的 Hatschekiidae 多样性仍需要进一步调查。
