Olifantiella pseudobiremis Riaux-Gobin emend. L. Li, C. P. Chen & Y. H. Gao, 2012

Li, Lang, Sun, Lin, Chen, Changping, Li, Xuesong, Liang, Junrong & Gao, Yahui, 2018, Epitypification and emendation of Olifantiella pseudobiremis, an epizoic diatom from the East China Sea Okinawa Trough, Phytotaxa 362 (3), pp. 292-296 : 293-295

Olifantiella pseudobiremis Riaux-Gobin emend. L. Li, C. P. Chen & Y. H. Gao ( Figs 2–16 )

Holotype: Fig. 66 designated by Riaux-Gobin & Al-Handal (2012).

Type locality: Port Mathurin beach, Rodrigues Island.

Isotypes: from sample “Port Mathurin 2”, sampled in June 2007, Slide BM 101461 deposited in the National History Museum (London, U.K.), slide ZU7/ 42 in the Hustedt Collection (Bremerhaven, Germany), slide “ ALH TRO GOT 121” in Collection A.Y. Al-Handal (Göteborgs Universitet, SE-405 30 Göteborg, Sweden) and slide ROD 1 in Collection C. Riaux-Gobin.

Epitype here designated: Slide labeled “2017 ECS & SYS F6 0403 © ”!, 3 April 2017, deposited in School of Life Sciences, Xiamen University, China.

Epitype locality: Okinawa Trough, East China Sea.

Description: Cells solitary. One plastid consists of two plates lying on opposite sides of the girdle ( Fig. 2 ). Valves elliptical to oblong, with broadly rounded to rostrate apices, lightly silicified ( Figs 3, 4 ). Frustules 4.6–6.8 μm long, 2.3–3.5 μm wide, ratio of length to width 2.0 ± 0.3. Valve face flat ( Fig. 8 ). Striae parallel to radiate, equidistant, 33–45 in 10μm. Each stria composed of one macroareola ( Figs 5, 8 ). Four rounded areolae located at each apex ( Figs 5, 9 ). Axial area linear, narrow ( Fig. 5 ). Central area weakly expanded ( Fig. 5 ). External process opening close to the central area, oblong and slightly bent ( Figs 7, 8, 10 ). Raphe simple, straight ( Figs 5, 8, 11, 12 ). Central raphe endings straight, simple, close to each other, dramatically inflated towards the process opening ( Figs 7, 10, 14, 15 ). Terminal raphe endings simple, not protracted, slightly deflected to the secondary side ( Figs 5, 9, 11–13 ). A marginal channel with silica frames (in zig-zag) on the roof and on the floor, running around the valve, without partition walls ( Figs 8, 11, 12 ). This channel opens to the outside by fenestrulae partially closed by a granular velum, which is different from the finely perforated hymenes of the macroarolae ( Figs 9, 10 ). A small open pore without any ornamentation present on each fenestrula ( Figs 9, 10 ). Floor of the frame covered with hymenes ( Figs 11, 13 ). Buciniportula composed of two low but hollow structures, close to a hemispherical siliceous wart in between central raphe endings internally ( Figs 14, 15 ). Girdle bands several, with two or three rows of puncta occluded by vela ( Fig. 16 ).

Ecology: In the sampling site, water temperature increased gradually from 4.51 (bottom) to 22.13 º (surface), and water salinity was 34.66 ± 0.28 ppt. Our copepod specimen was collected from open waters, and the diatom removed from the copepod was considered to be epizoic.

Figures

FIGURES 2–16. Olifantiella pseudobiremis (2–4. LM; 5–7. TEM; 8–16. SEM). 2. One cell with chloroplast. 3, 4. Cleaned frustules, epitype here designated. 5. Morphology of the entire valve. 6. Marginal channel showing hymenes. 7. View of the process opening and the inflated central raphe endings. 8. External view of the entire valve. 9. External detail of the terminal raphe ending, each fenestrula closed by a granular velum except for a small round pore. 10. External detail of the process opening and the inflated central raphe endings. 11. Internal view of the entire valve showing the floor of the marginal channel covered with hymenes. 12. Corroded valve showing the silica frame on the floor of the marginal channel. 13. Internal detail of the apex with terminal raphe ending. 14, 15. Internal detail of the central area with a paired buciniportulae and a hemispherical siliceous wart in between the central raphe endings. 16. Girdle view showing corroded fenestrulae on the mantles and blurry puncta on the cingular bands. Scale bars in Figs 2–4 = 5 μm; Figs 5, 8, 11, 12 = 1 μm; Figs 6, 7 = 0.2 μm; Figs 9, 10, 13, 15, 16 = 0.5 μm; Fig. 14 = 0.25 μm.