Ulnaria qinghainensis Bing Liu, 2023
Liu, Bing, 2023, The diatom genus Ulnaria (Bacillariophyta) in China, PhytoKeys 228, pp. 1-118 : 1
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publication ID |
https://dx.doi.org/10.3897/phytokeys.228.101080 |
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persistent identifier |
https://treatment.plazi.org/id/DBEF86D6-86F0-551A-BC60-6131B3ADF5CF |
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treatment provided by |
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scientific name |
Ulnaria qinghainensis Bing Liu |
| status |
sp. nov. |
Ulnaria qinghainensis Bing Liu sp. nov.
Figs 57 View Figure 57 , 58 View Figure 58 , 59 View Figure 59 , 60 View Figure 60
Holotype.
Slide JIUDIA202310, specimen circled on slide, illustrated as Fig. 57C View Figure 57 .
Registration.
PhycoBank http://phycobank.org/103816.
Type locality.
China. Qinghai province: Chengduo County, Baima River, at a sampling location (33°22'21"N, 97°0'18"E, 3690 m a.s.l.), collected by Bing Liu, July 22, 2019.
Description.
LM (Fig. 57 View Figure 57 ). Frustule rectangular in girdle view (Fig. 57A View Figure 57 ). Valves linear-lanceolate with sub-capitate apices (Fig. 57B-N View Figure 57 , see also Figs 58A View Figure 58 , 59A View Figure 59 ). Valve dimensions (n = 35): length 88-223 μm, width 3.1-5.0 μm at centre. Sternum distinct, extending length of valve. Central area completely absent. Striae parallel, radiate at apices, and mostly opposite one another across sternum. Stria density 9-11 in 10 μm.
SEM (Figs 58 View Figure 58 - 60 View Figure 60 ). Valve characterized by a series of relatively wide virgae, interconnected with vimines (Fig. 58B-F View Figure 58 ). Striae uniseriate. Stria mostly opposite across sternum, equidistant until radiate at poles, areolae often apically elongated, especially near the mantle (Figs 58B-F View Figure 58 , 59B, C, E View Figure 59 ). Central area completely absent (Figs 58B View Figure 58 , 59B View Figure 59 ). Ocellulimbus composed of ca. 18 pervalvar and 9 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Fig. 58D View Figure 58 , two arrows). One rimoportula located at each pole, externally expressed as a simple hole (Fig. 58D, F View Figure 58 ), internally bilabiate, situated close to sternum (Fig. 59D, F View Figure 59 ). Valvocopula closed, surrounding the valve internal margin (Fig. 60A View Figure 60 ), bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 60B-F View Figure 60 ), lacking ornamentation at both poles (Fig. 60D, F View Figure 60 ). On its advalvar edge, valvocopula has a row of serrated projections, each corresponding internally to a virga (Fig. 60B, C, E View Figure 60 ).
Etymology.
Named after Qinghai province, where this species was found.
Ecology and distribution.
Epilithic in a plateau river. Ulnaria qinghainensis and U. chengduoensis were commonly found in the same sampling site. The environmental parameters were measured in the field and the results are given in the description of the former taxon above. So far, its distribution is known only from the type locality.
Discussion.
Ulnaria qinghainensis is characterized by its linear-lanceolate valve outline, lacking central area, sub-capitate apices, and slender valves. It differs from U. obtusa (W. Smith) E. Reichardt by its narrower valves (3.1-5.0 μm vs 5-8 μm) and its much higher stria density (9-11 in 10 μm vs 3-4 in 10 μm) (see Williams and Van de Vijver 2021, p. 175).
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