Ulnaria shun-biseriata Bing Liu & Rioual, 2024

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, PhytoKeys 246, pp. 315-327 : 315-327

publication ID	https://doi.org/ 10.3897/phytokeys.246.130942
DOI	https://doi.org/10.5281/zenodo.13834273
persistent identifier	https://treatment.plazi.org/id/0772BC18-1D30-5679-A729-B75678CA0958
treatment provided by	PhytoKeys by Pensoft
scientific name	Ulnaria shun-biseriata Bing Liu & Rioual
status	sp. nov.

Treatment

Ulnaria shun-biseriata Bing Liu & Rioual sp. nov.

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

Holotype.

A specimen circled on the Slide DIA 2024008 About DIA , deposited in the herbarium of Jishou University ( JIU), China, illustrated here as Fig. 1 A View Figure 1 . Registration. Phycobank http://phycobank.org/104927. GoogleMaps

Type locality.

China • Hunan Province: Lanshan County, Shun River GoogleMaps , 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 View Figure 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 View Figure 1 ) or a hyaline area which extends to one margin with the other side bordered with a few shortened striae (Fig. 1 A, G – I View Figure 1 ). Ghost striae sometimes present (e. g. Fig. 1 C, D View Figure 1 ) 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 View Figure 1 ) than normal valves (Fig. 1 A – I View Figure 1 ).

SEM (Figs 2 View Figure 2 – 4 View Figure 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 View Figure 2 – 4 View Figure 4 ). Valves with mixed striae, mostly biseriate. Two rimoportulae per valve, one at each pole, externally expressed as simple holes (Fig. 2 E View Figure 2 ), internally bilabiate, situated close to sternum (Fig. 4 E View Figure 4 ). Ocellulimbus composed of pervalvar columns and transverse rows of porelli (Fig. 2 D View Figure 2 , 3 C View Figure 3 ). A few serrated apical outgrowths protruding over the ocellulimbus (Fig. 2 E View Figure 2 ). Valvocopula is a closed hoop, attached to the mantle interior, surrounding internal valve margin (Fig. 4 C – F View Figure 4 ). Each valvocopula bears a mostly continuous row of poroids dividing the pars interior from pars exterior, located at midline (Fig. 3 B – C View Figure 3 , arrows); lacking ornamentation at either apex (Fig. 4 E, F View Figure 4 , arrow respectively). On its advalvar edge, valvocopula bears a row of serrated projections, each corresponding internally to a virga (Fig. 4 D View Figure 4 , 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.