Zhou Tong, Wang Zhe, Yang Hao, Gu Zemao
Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, PR China.
Hubei Engineering Technology Research Center for Aquatic Animal Diseases Control and Prevention, Wuhan, 430070, PR China.
Int J Parasitol Parasites Wildl. 2019 Sep 24;10:289-298. doi: 10.1016/j.ijppaw.2019.09.006. eCollection 2019 Dec.
Data on sessilinasis from are limited. This study investigates sessilid diversity in Hubei Province, China in 2016. pereopods were covered by two sessilid morphotypes in April and May, and the gills were adhered by one of these two morphotypes (morphotype I) in January. Identifying the two morphotypes according to their morphological characters through live observations and protargol-stained method is difficult. Both morphotypes show almost identical morphological characteristics: zooids present vase-shaped, the length-to-width ratio is 2:1, the semicircle-shaped peristomial disk is evidently above the peristomial lip, single contractile vacuole is located below the peristomial lip, and the oral infraciliature shows identical arrangement which can be distinguished from other . However, the morphometric data of the two morphotypes are significant different: body size of morphotype I is 78.9-103.8 × 32.1-54.6 μm, whereas that of morphotypes II is 136.7-171.5 × 60.9-88.0 μm. To further identify the two morphotypes, molecular regions including small subunit ribosomal DNA (SSU rDNA) sequences, large subunit ribosomal DNA (LSU rDNA) sequences, and ITS1-5.8S-ITS2 sequences were used. Results supported that the two morphotypes are single species of genus rather than distinct species based in their distinct size ranges and temporal presence events. We assigned it the name n. sp. with respect to the semicircular peristomial disk. Overall, these findings emphasized the importance of using molecular data to solve the identification confusion caused by ontogenetic processes. This study is the first morphological and molecular characterization of a sessilid isolated from under aquaculture conditions.
关于[具体来源未提及]的柄苔藓虫的数据有限。本研究调查了2016年中国湖北省的柄苔藓虫多样性。在4月和5月，步足被两种柄苔藓虫形态型覆盖，而在1月，鳃被这两种形态型之一（形态型I）附着。通过活体观察和原银染法根据形态特征鉴定这两种形态型很困难。两种形态型显示出几乎相同的形态特征：类个体呈瓶状，长宽比为2:1，半圆形的围口盘明显高于围口唇，单个伸缩泡位于围口唇下方，口下纤毛排列相同，可与其他[未提及的对象]区分开来。然而，两种形态型的形态测量数据有显著差异：形态型I的体长为78.9 - 103.8×32.1 - 54.6μm，而形态型II的体长为136.7 - 171.5×60.9 - 88.0μm。为了进一步鉴定这两种形态型，使用了包括小亚基核糖体DNA（SSU rDNA）序列、大亚基核糖体DNA（LSU rDNA）序列和ITS1 - 5.8S - ITS2序列在内的分子区域。结果支持这两种形态型是[未提及的属]的单一物种，而非基于其不同大小范围和时间出现情况的不同物种。鉴于半圆形的围口盘，我们将其命名为[未提及的新物种名称]。总体而言，这些发现强调了利用分子数据解决由个体发育过程引起的鉴定混淆的重要性。本研究是在水产养殖条件下从[未提及的对象]分离出的柄苔藓虫的首次形态学和分子特征描述。
