中国淡水硅藻新记录——偏肿内丝藻兴凯变种

于2016年5月对浙江省仙居国家公园进行藻类多样性调查时,发现了中国淡水硅藻的1个新记录种——偏肿内丝藻兴凯变种[Encyonema ventricosum var.hankensis(Skvortzov) RodionovaPomazkina]。该文采用光镜和扫描电镜对偏肿内丝藻兴凯变种浙江种群的形态特征进行了观察和描述,并将其与该种的其他地理种群及内丝藻属其他相似物种的形态特征进行比较,同时讨论了该物种的生境特征。结果表明:(1)偏肿内丝藻兴凯变种壳面均具明显背腹之分,背缘明显拱起,腹缘轻微波曲;端部呈头状至喙状。(2)偏肿内丝藻兴凯变种浙江地理种群在背部中央区域具一孤点,而其兴凯种群对孤点这一特征未有描述。(3)偏肿内丝藻兴凯变种在俄罗斯的兴凯湖和贝加尔湖等地有分布,该种在中国是首次报道。

Encyonema ventricosum var. hankensis, a Newly Recorded Freshwater Diatom in China

During a survey of freshwater diatoms from Shibadukeng stream in the Xianju National Park, Zhejiang Province, China, a newly recorded diatom, Encyonema ventricosum var. hankensis (Skvortzov) Rodionova & Pomazkina was recorded. Based on the application of light microscope (LM) and scanning electron microscope (SEM), E. ventricosum var. hankensis was identified and described here in details. The morphological differences between Zhejiang population and two Russia populations and other similar Encyonema species were compared. In addition, the habitat characteristics of Encyonema ventricosum var. hankensis in Shibadukeng stream were supplied in our paper. The results show that: (1) E. ventricosum var. hankensis valves strongly dorsiventral, dorsal margin broadly arched, ventral margin moderately undulant, apices capitate, deflected to the ventral margins. (2) E. ventricosum var. hankensis Zhengjiang population has a stigma on the dorsal side of the center area, while the Lake Khanka population and Lake Baikal population are no recorded. (3) E. ventricosum var. hankensis is found in Lake Khanka and Lake Baikal, and this is the first report from the freshwater in China.