Ulnaria wuling-biseriata 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/96A4A27C-9D80-52D2-B6EB-4C0B0A645655

treatment provided by

PhytoKeys by Pensoft

scientific name

Ulnaria wuling-biseriata Bing Liu
status

sp. nov.

Ulnaria wuling-biseriata Bing Liu sp. nov.

Figs 35 View Figure 35 , 36 View Figure 36 , 37 View Figure 37 , 38 View Figure 38

Holotype.

Slide JIUDIA202305, specimen circled on slide, illustrated as Fig. 35A View Figure 35 .

Registration.

PhycoBank http://phycobank.org/103811

Type locality.

China. Hunan province: Zhangjiajie National Forestry Park, Jinbian stream, at Shuirao Simen (29°20'36"N, 110°28'13"E, 467 m a.s.l.), collected by Bing Liu, December 29, 2015.

Description.

LM (Fig. 35 View Figure 35 ). Valves linear with abruptly tapering rostrate to sub-capitate apices (Fig. 35A-J View Figure 35 , see also Figs 36A, E View Figure 36 , 37A, E View Figure 37 ). Valve dimensions (n = 15): length 160-200 μm, width 6.5-8 μm at centre. Sternum discernible, mostly regular, occasionally irregular (e.g., Fig. 35D View Figure 35 ), extending length of valve. Central area apically rectangular or trapezoid. Ghost striae sometimes present in central area (e.g., Fig. 35C, I View Figure 35 ). Striae parallel, radiate only at each pole, and mostly opposite across sternum. Stria density 10-11 in 10 μm.

SEM (Figs 36 View Figure 36 - 38 View Figure 38 ). Valves mostly with mixed striae, each composed of a biseriate main part and a uniseriate minor part (including several areolae) near sternum (Figs 36B-D, F View Figure 36 , 37B-D, F View Figure 37 ). But some uniseriate striae occurring near each apex (Fig. 36C, D View Figure 36 ). One rimoportula at each pole, externally expressed as a simple hole (Fig. 36C, D View Figure 36 ), internally bilabiate, situated close to sternum (Figs 37C, D View Figure 37 , 38D View Figure 38 ). Ocellulimbus composed of ca. 24 pervalvar and 8 transverse rows of porelli. Valvocopula a closed hoop (Fig. 38A View Figure 38 ), with a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 38B, C, E View Figure 38 ). A row of serrated projections is located on its advalvar edge, each corresponding internally to a virga (Fig. 38B, C View Figure 38 ), unornamented at both poles (Fig. 38C, F View Figure 38 ).

Etymology.

The epithet " wuling-biseriata " is a combination of Wuling and the term biseriate to reflect its type locality (Wuling Mountains) and its mostly biseriate striae.

Ecology and distribution.

Ulnaria wuling-biseriata was commonly found in the surface sediment collected in Jinbian stream with U. pandurata-biseriata and U. ulnabiseriata . Thus, U. wuling-biseriata lives on the stone surfaces of the headwaters of a mountainous stream. So far, its distribution is known only from the type locality.

Discussion.

Ulnaria wuling-biseriata is characterized by its linear valve outline, mostly biseriate striae, rectangular or trapezoid central area, and rostrate to sub-capitate apices. The apices of Ulnaria ulna var. spathulifera Aboal sometimes have an inflation before tapering to form subrostrate to rostrate ends whereas U. wuling-biseriata does not have this inflation, i.e., its apex is not spatulate. Moreover, the valves of U. ulna var. spathulifera are wider than the ones of U. wuling-biseriata (8-9 μm vs 6.5-8 μm) and the former has lower stria density than the latter (9-10 in 10 μm vs 10-11 in 10 μm) (see Morales et al. 2007, p. 34, as Synedra ulna var. spathulifera ).