Ulnaria hupingensis Bing Liu, 2023

Liu, Bing, 2023, The diatom genus Ulnaria (Bacillariophyta) in China, PhytoKeys 228, pp. 1-118 : 1

publication ID	https://dx.doi.org/10.3897/phytokeys.228.101080
persistent identifier	https://treatment.plazi.org/id/1CD231CE-B032-5419-BAB5-8A1D2DBBE385
treatment provided by	PhytoKeys by Pensoft
scientific name	Ulnaria hupingensis Bing Liu
status	sp. nov.

Treatment

Ulnaria hupingensis Bing Liu sp. nov.

Figs 67 View Figure 67 , 68 View Figure 68 , 69 View Figure 69 , 70 View Figure 70 , 71 View Figure 71 , 72 View Figure 72

Holotype.

Slide JIUDIA202312, specimen circled on slide, illustrated as Fig. 68B View Figure 68 .

Registration.

PhycoBank http://phycobank.org/103818.

Type locality.

China. Hunan province: Huping Mountain National Nature Reserve, Xie River, a sampling location (30°1'9"N, 110°37'46"E, 400 m a.s.l.), collected by Bing Liu, March 14, 2021.

Description.

LM (Figs 67 View Figure 67 , 68 View Figure 68 ). Living cells with numerous discoid chromatophores (Fig. 67A-E View Figure 67 , note that these cells may be in an unhealthy condition). Frustule in girdle view rectangular (Figs 67A-C View Figure 67 , 68A View Figure 68 , see also Fig. 69A View Figure 69 ). Valves lanceolate with protracted, rostrate to sub-capitate poles (Figs 67D, E View Figure 67 , 68B-M View Figure 68 , see also Figs 70A View Figure 70 , 71A View Figure 71 , 72A View Figure 72 ). Valve dimensions (n = 59): length 81-200 μm, width 5.4-7.0 μm at centre. Sternum distinct, extending length of the valve. Central area completely absent. Striae parallel, radiate only approaching each apex, and mostly opposite one another across sternum. Stria density 9.5-11.5 (often 11) in 10 μm.

SEM (Figs 69 View Figure 69 - 72 View Figure 72 ). Frustule comprising several girdle bands (Fig. 69A-F View Figure 69 ). Epivalve associated with valvocopula and two copulae (Fig. 69D View Figure 69 , labelled B1 to B3, B1 = Valvocopula); number of copulae associated with hypovalve not verified. Valvocopula a closed hoop, same shape as valve outline, closely attached to mantle interior, surrounding valve margin (Fig. 70A View Figure 70 ), bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at midline (Fig. 70B-F View Figure 70 ), poroids lacking at centre of the valve (Fig. 70B View Figure 70 , two arrows). On its advalvar edge, valvocopula bears a row of serrated projections, each corresponding to a virga internally (Fig. 70C, E View Figure 70 , three arrows, respectively). Valvocopula lacking ornamentation at both poles (Fig. 70D, F View Figure 70 ). Valve face and mantle intersecting almost at right angle (Fig. 71A, B View Figure 71 ). Valve characterized by a series of relatively wide virgae, interconnected with vimines and closing plates affixed with few struts to the areola wall (Fig. 71B View Figure 71 ). Striae uniseriate (Figs 71B View Figure 71 , 72B-E View Figure 72 ), continuing onto mantle (Fig. 69B-F View Figure 69 ). Ocellulimbus composed of ca. 19 pervalvar and 11 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Figs 69F View Figure 69 , 71C-F View Figure 71 , two arrows, respectively). Internally, virgae transversely extending from sternum to mantle, striae situated almost opposite each other across sternum, areolae become more elongated closer to the mantle (Fig. 72B-E View Figure 72 ). Central area completely lacking (Figs 71A, B View Figure 71 , external, 72A, B, internal). One rimoportula usually present at each pole, occasionally two produced at one end (Figs 70D View Figure 70 , two arrows, 71D). External opening of rimoportula expresses as a simple hole, forming different shapes (Fig. 71C-F View Figure 71 ); internally bilabiate, situated close to sternum at an angle (Fig. 72D-F View Figure 72 ).

Etymology.

Named after Huping Mountain National Nature Reserve, where the species was found.

Ecology and distribution.

Epilithic in a mountain stream with oligotrophic waters. The following environmental parameters were measured in the field: Conductivity was 263 ± 1 μS ∙cm-1, pH was 8.4 ± 0.1 and water temperature was 12.4 ± 0.4 °C. So far, its distribution is known only from the type locality.

Discussion.

Ulnaria hupingensis is characterized by its lanceolate valve outline, lacking central area, and rostrate to sub-capitate apices. It differs from U. qinghainensis by its wider valves (5.4-7.0 μm vs 3.1-5.0 μm) and from U. obtusa by its much higher stria density (9.5-11.5 in 10 μm vs 3-4 in 10 μm) (see Williams and Van de Vijver 2021, p. 175).