Ulnaria fanjingensis 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/FE58F79A-717B-52AB-BFB5-BCEDE4E737A7
treatment provided by	PhytoKeys by Pensoft
scientific name	Ulnaria fanjingensis Bing Liu
status	sp. nov.

Treatment

Ulnaria fanjingensis Bing Liu sp. nov.

Figs 61 View Figure 61 , 62 View Figure 62 , 63 View Figure 63 , 64 View Figure 64 , 65 View Figure 65 , 66 View Figure 66

Holotype.

Slide JIUDIA202311, specimen circled on slide, illustrated as Fig. 62D View Figure 62 .

Registration.

PhycoBank http://phycobank.org/103817.

Type locality.

China. Guizhou province: Fanjing Mountain National Nature Reserve, Heiwang river, near Mile Daochang (27°49'10"N, 108°46'18"E, 494 m a.s.l.), collected by Bing Liu, December 31, 2015.

Description.

LM (Figs 61 View Figure 61 , 62 View Figure 62 ). Living cells with numerous plate-like chromatophores (Fig. 61A-F View Figure 61 , note that these cells may be in an unhealthy condition). Valves lanceolate, narrow, with rostrate to sub-capitate apices (Figs 61E, F View Figure 61 , 62A-N View Figure 62 ). Valve dimensions (n = 56): length 165-291 μm, width 4.8-6.3 μm at centre. Sternum distinct, extending length of valve. Central area extending to both margins forming apically rectangular fascia. Striae parallel, radiate only approaching each apex, and mostly opposite one another across sternum. Stria density 9-12 (often 10) in 10 μm.

SEM (Figs 63 View Figure 63 - 66 View Figure 66 ). Frustule rectangular in girdle view (Fig. 63A View Figure 63 , see also Fig. 61A-C View Figure 61 ). Striae continuing onto mantle, absent from centre (Fig. 63B View Figure 63 ). Epivalve associated with valvocopula and two copulae (Fig. 63B-D, bands View Figure 63 labelled B1-B3, B1 = valvocopula); hypovalve associated with valvocopula and one copula (Fig. 63C, D, bands View Figure 63 labelled B1-B2, B1 = valvocopula), forming a 3:2 configuration of girdle bands. Valvocopula a closed hoop, same shape as valve outline, closely attached to mantle interior (Fig. 64A View Figure 64 ), bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 64B-F View Figure 64 ), interrupted in the middle (Fig. 64B View Figure 64 , two arrows). A row of serrated projections is present on its advalvar edge, each corresponding internally to a virga (Fig. 64C, D View Figure 64 , five arrows respectively), lacking ornamentation at both poles (Fig. 64E, F View Figure 64 ). Each ocellulimbus composed of ca. 12 transverse rows (unequal in length) and ca. 18 pervalvar rows (unequal in length) (Figs 63E, F View Figure 63 , 65F View Figure 65 ). A few serrated apical outgrowths protruding over ocellulimbus, largest two appearing horn-like (Figs 63F View Figure 63 , 65E, F View Figure 65 , two arrows, respectively). Valve face and mantle intersecting almost at right angle (Fig. 65A-F View Figure 65 ). Valve characterized by a series of relatively wide virgae, interconnected with thin vimines and closing plates affixed with a few struts to each areolar wall (Fig. 65D-F View Figure 65 ). Valves with uniseriate striae; each series situated mostly opposite each other, equidistant until radiate at poles (Fig. 66A-F View Figure 66 ). Central area apically rectangular, extending to both margins (Figs 65B, C View Figure 65 , external, 66B, C, internal). One rimoportula located at each pole (Figs 65E View Figure 65 , 66E, F View Figure 66 ). External opening of rimoportula expressed as a simple hole (Fig. 65E View Figure 65 ); internally bilabiate, situated close to sternum, aligned with striae (Fig. 66E, F View Figure 66 ).

Etymology.

Named after Fanjing Mountain, where the species was found.

Ecology and distribution.

The sampling site is close to the headwaters of Heiwan River, which originates in the Fanjing Mountain National Nature Reserve. The diatom samples were scraped off of the stone surfaces. The following environmental parameters were measured in the field. Electric conductivity was 54.9 ± 1.4 μS ∙cm-1, pH was 7.6 ± 0.1, and water temperature was10.4 ± 0.1 °C. Since the diatom sample was scraped off of the surfaces of stones and the conductivity is below 100 μS ∙cm-1, U. fanjingensis can be considered an epilithic diatom characteristic of poor electrolyte content fresh water. So far, its distribution is known only from the type locality.

Discussion.

Ulnaria fanjingensis is characterized by its lanceolate valve outline, apically rectangular central area, rostrate to sub-capitate apices, and long valves. It is similar to U. dongtingensis Bing Liu, but they have different valve outlines: U. dongtingensis has narrow-lanceolate valves with parallel central margins the length of the central area whereas U. fanjingensis has parallel central margins extending beyond the central area (see Liu et al. 2019b, p. 134, fig. 14).