Plagiostriata xiapuensis W.Y.Zhang, Z.Wang, Y.H.Gao & C.P.Chen, 2022

Zhang, Weiyu, Wang, Zhen, Zhuo, Suqing, Gao, Yahui, Li, Xuesong, Liang, Junrong & Chen, Changping, 2022, Two new species of Plagiostriata (Bacillariophyaceae) from sand sediments of southern China, Phytotaxa 556 (1), pp. 87-93 : 88

Plagiostriata xiapuensis W.Y.Zhang, Z.Wang, Y.H.Gao & C.P.Chen sp. nov. (LM Figs 1–4 , SEM Figs 5–12 )

Description:—LM: Cells solitary. Frustules rectangular in girdle view. Valves linear elliptical to elliptical with obtusely rounded to cuneate apices. Valve dimensions: length 4.9~8.2 μm, breadth 1.8~2.6 μm ( Figs 1–4 ). The sternum and striae are invisible.

SEM: Valve face flat. The ventral mantle is deep and the dorsal mantle is wide ( Figs 5–9 ). Uniseriate striae along both sides of sternum alternately distributed or oppositely distributed, arranged in parallel, 32~ 34 in 10 μm ( Figs 9, 12 ). Virgae wider than vimines, merging with sternum at valve centre. Sternum indistinct. Areolae round, occluded by simple volae ( Fig. 10 ). Rimoportula located within a stria situated at valve centre, few valves with no rimoportulae near centre ( Figs 5–7, 9 ). Externally, the rimoportula appears as a slit-like opening that is elongated in parallel with striae. Internally, rimoportula are also simple, with slight siliceous thickenings ( Fig. 11 ). Two semilunar pores are observed at both poles, which are more like fissures, forming simple apical pore fields ( Figs 8, 10 ).

Type:— CHINa. Fujian = Province, Xiapu County, Ningde City : Dajing Beach , sand sample from intertidal, low tide area, 26°42 ‘34 “N, 120°7’ 17” E, May 2018, Z. Wang (holotype slide N202101! = Fig. 1 ; isotype Slide NI 202101, both at School of Life Sciences , Xiamen University, Xiamen, People’s Republic of China).

Etymology:—The epithet “ xiapuensis ” derives from the site where the specimen was found.

Figures

FIGURES 1–4. LM micrographs of Plagiostriata xiapuensis sp. nov. from type material. Fig. 1 corresponds to the holotype. Scale bars = 10 μm.

FIGURES 5–12. Plagiostriata xiapuensis sp. nov from type material, SEM. 5–7. External views of the valve with a rimoportula (arrow). 8. Apical fields of the external valve. 9. Central area of a valve with no rimoportula. 10. Apical fields of the internal valve. Areolae round, occluded by simple vola (arrows). 11, 12. Internal views of the valve with a rimoportula (arrow). Scale bars = 1 μm (Figs. 5–7, 9, 11, 12), 0.2 μm (Figs. 8, 10).