Surirella wufluminensis Bing Liu & Kociolek, 2022

Long, Ji-Yan, Kociolek, John Patrick, Williams, David M., Liu, Bing, Mo, Wen-Hui & Chen, Jin-Hua, 2022, Two new freshwater species of Surirella (Bacillariophyta) from the Wuling Mountains, China, PhytoKeys 201, pp. 35-49 : 35

publication ID

https://dx.doi.org/10.3897/phytokeys.201.79626

persistent identifier

https://treatment.plazi.org/id/9FE5A347-FE10-5797-A31A-A0D7C8D6F211

treatment provided by

PhytoKeys by Pensoft

scientific name

Surirella wufluminensis Bing Liu & Kociolek
status

sp. nov.

Surirella wufluminensis Bing Liu & Kociolek sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4

Holotype.

Holotype BM! 81892, specimen circled on slide, illustrated as Fig. 1D View Figure 1 ; isotype JIU! G202106, specimen circled on slide, illustrated as Fig. 1C View Figure 1 .

Type locality.

China. Hunan province: the course of Wu River, a sampling point at Changpu Town, Suining County, 26°34.59'N, 110°09.19'E, 300 m a.s.l., collected by Bing Liu, March 22, 2021.

Description.

LM (Fig. 1 View Figure 1 ). Valves twisted, sometimes exhibiting linear-lanceolate valve outline (Fig. 1D View Figure 1 ), with twisted and deflected apices (Fig. 1A-C View Figure 1 ). Valve dimensions (n = 27): 198-295 μm long, 41-50 μm wide. Valve face smooth without undulations, valve midline sigmoid, fibulae very distinctive, 20-28 in 100 μm. The degree of rotation (twist) of the valves differs (Fig. 1A-D View Figure 1 ) as each position relative to the observer is different. Two type valves are observed under LM: one is counterclockwise twisted (Fig. 1A, C View Figure 1 ), the other is clockwise twisted (Fig. 1B, D View Figure 1 ), also seen in SEM (Fig. 2A-F View Figure 2 ).

SEM (Figs 2 View Figure 2 - 4 View Figure 4 ). Valve twisted, but visual discrepancies of degree of twist differs (Fig. 2A-F View Figure 2 ). Valve surface flat without undulations but mound-like siliceous outgrowths scattered throughout (Figs 2A-C View Figure 2 , 3A-D View Figure 3 ). Very shallow depressions close to mantle, corresponding to beneath, internal fibulae (Fig. 3B View Figure 3 , four arrows). Raised longitudinal ridges produced on both sides of raphe (Fig. 3C View Figure 3 ). Externally, costae (thickened silica ribs) absent, external openings of areolae slit-like on both valve face and mantle (Fig. 3D, E View Figure 3 ). External distal raphe endings interrupted at both apices (Figs 3F, G View Figure 3 , 4D View Figure 4 ). Internally, distal raphe endings interrupted only at one apex where two helictoglossa-like processes present (Fig. 4E View Figure 4 ), raphe continuous at another apex (Fig. 4F View Figure 4 ). Mantle with same striation patterns as valve face and its base margin thickened (Figs 3E, F View Figure 3 , 4C View Figure 4 ). Fibulae distinctive, extending from mantle, spanning 1/3 to 1/2 of half valve width except near two apices where fibulae meeting at midline (Figs 2D-F View Figure 2 , 4A View Figure 4 ). Uniseriate striae 40-42 in 10 μm (measured in SEM images, n = 3). Internal openings of areolae rounded, rimmed (Fig. 4C, F View Figure 4 ). One portula and ca. 15-23 uniseriate striae located between two adjacent fibulae (Fig. 4A, B View Figure 4 ).

Etymology.

Named after Wu River, where the species was found.

Ecology and distribution.

Epilithic in a mountain river with oligotrophic waters. The following environmental parameters were measured in the field. Conductivity was 99.7 ± 0.3 μS ∙cm-1, pH was 7.9 ± 0.1 and water temperature was 13.2 ± 0.2 °C.