Ulnaria shun-biseriata Bing Liu & Rioual 2024, sp. nov.
Creators: name: Zheng, Yan
name: Liu, Bing
name: Rioual, Patrick
name: Long, Ji-Yan
name: Zhou, Min
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Plantae
Ochrophyta
Bacillariophyceae
Licmophorales
Ulnariaceae
Ulnaria
Ulnaria shun-Biseriata

description: Ulnaria shun-biseriata Bing Liu & Rioual sp. nov.
Figs 1, 2, 3, 4
Holotype.
A specimen circled on the Slide DIA 2024008, deposited in the herbarium of Jishou University (JIU), China, illustrated here as Fig. 1 A. Registration. Phycobank http://phycobank.org/104927.
Type locality.
China • Hunan Province: Lanshan County, Shun River, at a sampling site (25 ° 14 ' 55 " N, 112 ° 8 ' 32 " E, 400 m asl.), collected by Bing Liu, October 5, 2021.
Description.
LM (Fig. 1). Valves lanceolate with slightly undulate valve margins and apiculate apices. Valve dimensions (n = 41): length 48–70 μm, width 8.3–10.7 μm at center. Sternum distinct, extending length of valve. Central area with two arrangements: an asymmetric hyaline region extending to both margins (Fig. 1 B – F) or a hyaline area which extends to one margin with the other side bordered with a few shortened striae (Fig. 1 A, G – I). Ghost striae sometimes present (e. g. Fig. 1 C, D) in the central area. Striae parallel, mostly opposite one another across sternum. Stria density 8.5–11 (often 10) in 10 μm. Many abnormal valves found, all of which exhibit an asymmetry relative to the apical axis due to the valve middle part only expanding on one side, and more undulate valve margins (Fig. 1 J – Q) than normal valves (Fig. 1 A – I).
SEM (Figs 2 – 4). Valves characterized by relatively wide virgae, interconnected with thin viminules, areolar closing plates having a few struts fixing them onto the areolar wall (Figs 2 – 4). Valves with mixed striae, mostly biseriate. Two rimoportulae per valve, one at each pole, externally expressed as simple holes (Fig. 2 E), internally bilabiate, situated close to sternum (Fig. 4 E). Ocellulimbus composed of pervalvar columns and transverse rows of porelli (Fig. 2 D, 3 C). A few serrated apical outgrowths protruding over the ocellulimbus (Fig. 2 E). Valvocopula is a closed hoop, attached to the mantle interior, surrounding internal valve margin (Fig. 4 C – F). Each valvocopula bears a mostly continuous row of poroids dividing the pars interior from pars exterior, located at midline (Fig. 3 B – C, arrows); lacking ornamentation at either apex (Fig. 4 E, F, arrow respectively). On its advalvar edge, valvocopula bears a row of serrated projections, each corresponding internally to a virga (Fig. 4 D, two arrows).
Etymology.
The specific epithet shun-biseriata is a combination of the Shun River and the adjective biseriate to reflect the type locality and the mostly biseriate character of the striae.
Distribution and ecology.
Known only from the type locality in which it is a common species with ca. 1 % relative abundance. The samples that included this species were scraped off the surface of stones collected in the Shun River. Hence this is a benthic, epilithic species. The associated taxa include Gyrosigma kuetzingii (Grunow) Cleve, Encyonema appalachianum Potapova, Pinnularia subgibba Krammer, P. borealis Ehrenberg, Gomphonema berggrenii Cleve, Epithemia spp., Nitzschia spp., Iconella spp., among others. The following environmental parameters were measured in the field with three replications: Conductivity = 70.1 ± 0.1 μS cm - 1; pH = 8.5 ± 0.1; Water temperature = 24.5 ± 0.1 ° C.
description: Published as part of Zheng, Yan, Liu, Bing, Rioual, Patrick, Long, Ji-Yan & Zhou, Min, 2024, Ulnaria shun-biseriata sp. nov. (Bacillariophyta) from the Shun River in Hunan Province, China, pp. 315-327 in PhytoKeys 246 on pages 315-327, DOI: 10.3897/phytokeys.246.130942