Taxonomic Study Of Marine Diatoms In Family Naviculaceae From Sandy Environment In Southern Fujian Province

In this study,surface sandy sediments were sampled from the four large sand-flats(Chongwu Xisha Bay in Quanzhou,Zengcuoan in Xiamen,Maluan Bay in Dongshan and Feicui Bay in Liuao,Zhangpu,Zhangzhou)in the southern coast of Fujian Province.The samples were collected from 2018 to 2020.The morphology of diatoms of family Naviculaceae was observed by light microscope and scanning electron microscope,and their taxonomic characteristics were described in detail.A total of 7 genera in of the Naviculaceae family were observed in this study,which are Cymatoneis,Fogedia,Haslea,Hippodonta,Navicula,Seminavis,Trachyneis.Among them,genus Navicula had the biggest amount species,including ten species,followed by genus Seminavis,which contain four species;There are fewer identified species in other genera.Two species are recorded for the genus Fogedia and Hippodonta,and one species is recorded for the genus Cymatoneis,Haslea and Trachyneis.A new diatom species and two new recored species of China were described.They are Seminavis exigua Chen,Zhuo&Gao sp.Nov.,Cymatoneis margarita Witkowski and Navicula agatkae Witkowski,Lange-Bertalot&Metzeltin.Seminavis exigua Chen,Zhuo&Gao sp.Nov.possesses the typical characteristics of genus Seminavis.The valve is semi-lanceolate with a convex dorsal margin and straight ventral margin.Mantle in dorsal sides is deep while ventral sides is absent and the areolae on valve is slit-like.The striae are parallel which present one to two rows on the ventral sides.The striae density is same on the ventral and dorsal.There is a single row of pores at the valve apices from external,which become chambers internal.This species is the smallest among the known of the genus.It has similar morphology with these species:S.strigose,S.macilenta,Amphora cymbellamphora,A.exilitata,and A.tenerrima.The result indicates that the diatom species of the family Naviculaceae in the intertidal sandy environment are relatively abundant.This study may be a reference for further research on diatom species diversity and taxonomy in similar habitat.