Tabularia sinensis, Cao & Yu & You & Lowe & Williams & Wang & Kociolek, 2018

Cao, Yue, Yu, Pan, You, Qingmin, Lowe, Rex L., Williams, David M., Wang, Quanxi & Kociolek, J. P., 2018, A new species of Tabularia (Kützing) Williams & Round from Poyang Lake, Jiangxi Province, China, with a cladistic analysis of the genus and their relatives, Phytotaxa 373 (3), pp. 169-183 : 180-181

Tabularia sinensis sp. nov. ( Fig. 2 = holotype)

TYPE:— CHINA, SHTU, slide PYH-201708-05, Shanghai Normal University, Biology Department Diatom Herbarium , Shanghai, China. Holotype illustrated in Fig. 2 .

LM: Valves linear, margins parallel, slightly swelling at centre, tapering to blunt, squared apices, valve length = 65–175 μm, breadth = 5.5–6.5 μm. Striae short, parallel to radiate, 13–15 in 10 μm, producing very wide sternum. Rimportula positioned near each valve apex, as simple opening on valve face, obliquely situated.

SEM: Externally, valve face ornamentation limited to margins and apices ( Figs 22–27 ). Each striae with longitudinally-oriented areolae, composed of wide virgae and slender vimines, covered by a cribrum (closing plate), occupying most of the opening ( Fig. 25 ). Cribrum solid, without subdivisions ( Figs 23, 25 ). On valve face, stria comprised of 4–7 areolae (complex of virgae and vimines), that nearest the sternum smaller than the rest; areolae extending onto valve mantle. Near 2 nd or 3 rd stria from each apex, a rimoportula evident by the narrow elliptical opening ( Fig. 23 ). Ocellulimbus sunken into mantle apex. Ocellulimbus comprised of 7–10 rows of round porelli. Two small, tapering spines at each pole, overhang ocellulimbus ( Figs 23, 24, 27 ).

Internally, valve dominated by broad sternum (lamina) extending entire length of valve ( Fig. 28 ). Rimoportula projects inwards, with distinctive paired thickened margins ( Fig. 29 ). Striae composed of a single opening, subdivided externally ( Figs 31–33 ). Ocellulimbus comprised of round porelli ( Fig. 30 ).

Girdle not well documented, valvocopula plain, tapering towards poles.

Isotype: COLO, slide 614007, Kociolek Collection, University of Colorado, Museum of Natural History Diatom Herbarium, Boulder, USA.

Type Locality: CHINA. Poyang Lake, Jiangxi Province

Etymology: Named for it being from China

Figures

FIGURES 1–21. Tabularia sinensis, series of LM micrographs. Figs 1–13: illustrate size ranges of entire valves; the linear valves have squared apices, an exceptionally wide sternum, a rimoportula at each pole; Figure 6 shows a girdle view, the frustule being slightly bent at either end, giving a gentle lunate shape; bar = 10μm. Figs 14–21: Various valves with detail of pole with rimoportula; bar = 10μm.

FIGURES 22–27. Tabularia sinensis, external view of valves, SEM. Fig. 22: External view of entire valve. Fig. 23: View of valve pole showing rimoportula within sternum, striae composed of robust virgae, slender vimines and cribra (closing plate) occupying most of the opening, a sunken ocellulimbus with small but wide spines just overhanging upper part of ocellulimbus. Fig. 24: Detail of upper part of sunken ocellulimbus. Fig. 25: Detail of striae with robust virgae, slender vimines and cribra (closing plate) occupying most of the opening. Fig. 26: Detail of valve margin with the suggestion of either very reduced or broken spines along the edge. Fig. 27: Detail of valve pole showing upper portion of sunken ocellulimbus with small overhanging spines.

FIGURES 28–33. Tabularia sinensis, internal view of valves, SEM. Fig. 28: Internal view of entire valve. Fig. 29: Detail of internal view of pole with twin protruding lips of rimoportula, obliquely situated within sternum, striae composed of robust virgae, vimines as slender cross-members, and a sunken ocellulimbus. Fig. 30: Detail of sunken ocellulimbus. Fig. 31: Detail of valve margin with robust virgae meeting at margin edge to form sternum. Fig. 32: Detail of valve with vimines as slender cross-members. Fig. 33: Detail of valve with vimines as slender cross-members with cribra (closing plate).