Slide JIUDIA202301, specimen circled on slide, illustrated as Fig. 14A.

PhycoBank http://phycobank.org/103807

China. Guizhou province: Fanjing Mountain, Temple Longquan, Heiwan River (27°51'36"N, 108°45'51"E, 532 m a.s.l.), collected by Bing Liu, December 31, 2015.

LM (Fig. 14). Valves linear-lanceolate, constricted at centre, apex rostrate to sub-capitate (Fig. 14A–H, see also Figs 16A, 17A, 18A, E). Valve dimensions (n = 35): length 66–166 μm, width 5.5–8 μm at constricted centre, narrower by 0.2–1.1 µm than at its widest. Valve margins parallel with rostrate to sub-capitate apices (Fig. 14A–H). Sternum central, distinct, extending whole length of valve. Rectangular or square central area. Ghost striae often present in central area (e.g., Fig. 14A–E). Striae parallel, radiate only at the poles. Striae mostly opposite one another across sternum. Stria density 10–12 (often 11) in 10 μm.

Figure 14. 

Ulnaria constricta-biseriata sp. nov., ×1000, LM A–H eight valves exhibiting a size diminution series, note the constricted middle margins A micrograph of holotype specimen. Scale bar: 20 μm.

SEM (Figs 15–18). Frustule in girdle view rectangular (Fig. 15A). Epivalve with up to three closed copulae (Fig. 16B–F), 2^nd and 3^rd copulae bearing two rows of poroids (2^nd = B2, Fig. 15B–E, white wavy arrow; 3^rd = B3, Fig. 15D, E, black arrow). Valvocopula closed, surrounding whole valve margin (Fig. 16A), bearing a mostly continuous row of poroids at the midline, dividing pars interior from pars exterior (Fig. 16B–D), lacking ornamentation at both poles (Fig. 16C, D); its advalvar edge having a row of serrated projections, each corresponding to a virga internally (Fig. 16B–D, two arrows respectively). Valve central area rectangular (Figs 17B, E, 18B, F). Striae constructed from series of relatively wide virgae interconnected with thin viminules, closing plates present with a few struts, affixed to the areolar wall (Figs 17B–F, 18B–D, F; closing plate see Fig. 17F, wavy arrow). Valves with mixed striae, mostly biseriate, formed by viminules; each stria situated opposite each other across sternum, equidistant until radiate at poles, and becoming uniseriate near sternum (Figs 17B–F, 18B–D, F). One rimoportula present at each pole, externally expressed as a simple hole (Fig. 17D, F), internally bilabiate, situated close to sternum (Fig. 18C, D). Apical pore fields ocellulimbus, consisting of ca. 23 pervalvar and 11 transverse rows of porelli (both pervalvar and transverse rows unequal in length). A few serrated apical outgrowths protruding over each ocellulimbus (Fig. 17C, D, F, one arrow respectively).

Figure 15. 

Ulnaria constricta-biseriata sp. nov., girdle view, SEM A a frustule with a collapsed hypovalve B–D details from A, note three copulae (labeled B1 to B3) associated with the epivalves and two rows of poroids present on B2 (wavy arrows) and B3 (arrows) E, F the apices with three copulae visible (labeled B1 to B3) associated with the epivalves and two rows of poroids produced on B2 (wavy arrow) and B3 (arrow). Scale bars: 20 μm (A); 3 μm (B–F).

Figure 16. 

Ulnaria constricta-biseriata sp. nov., internal view, SEM A a complete valve with a valvocopula B middle detail from A, note serrated projections at the advalvar edge (two arrows) C, D two apical details from A, note the closed nature of valvocopula and serrated projections at the advalvar edge (two arrows respectively). Scale bars: 20 μm (A); 4 μm (B–D).

Figure 17. 

Ulnaria constricta-biseriata sp. nov., external view, SEM A a complete valve B middle part from A showing the constricted middle margins and central area forming a rectangular hyaline region C, D two apical details from A, note a few serrated apical projections protruding over the ocellulimbus (two black arrows) E another middle part, note two constricted middle margins F another apex, note a few serrated apical projections protruding over the ocellulimbus (arrow) and the closing plates (wavy arrow). Scale bars: 20 μm (A); 2 μm (B–F).

Figure 18. 

Ulnaria constricta-biseriata sp. nov., internal view, SEM A a complete valve B middle part from A, note two constricted middle margins and some ghost striae C, D two apical details from A, note the striae mostly biseriate and two helictoglossae E another complete valve F middle detail from E, note two constricted middle margins and some ghost striae. Scale bars: 20 μm (A, E); 2 μm (B–D, F).

The specific epithet is formed from two terms: constrict and biseriate, reflecting the constricted valve central margins and the mostly biseriate striae of the valve.

The sampling site is close to the headwaters of the 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. Conductivity was 49.7 ± 0.2 μS∙cm^-1, pH was 7.7 ± 0.1 and water temperature was 9.4 ± 0.1 °C. So far, its distribution is known only from the type locality. To sum up, U. constricta-biseriata lives on the stone surfaces of the headwaters of a mountainous river.

Ulnaria constricta-biseriata is characterized by its linear-lanceolate valve outline, constricted valve central margins, and mostly biseriate striae. Ulnaria contracta (Østrup) E.A. Morales & M.L. Vis has also constricted valve central margins, but it differs from U. constricta-biseriata by its lanceolate valve outlines and mostly uniseriate striae (see Morales et al. 2007, p. 61, figs 48–55, p. 63, figs 56–61, as Synedra ulna var. contracta Østrup).

Slide JIUDIA202302, specimen circled on slide, illustrated as Fig. 20D.

PhycoBank http://phycobank.org/103808.

China. Hunan province: Jishou City, Lianaiqiao, Donghe River (28°18'51.3"N, 109°43'41.6"E, 200 m a.s.l.), collected by Bing Liu, December 9, 2016.

LM (Figs 19, 20). Frustules rectangular in girdle view (Figs 19A, B, 20A), lanceolate in valve view (Fig. 19C, D). Chloroplasts two long plates per cell, valve-appressed (Fig. 19A), covering large portion of valve face in valve view (Fig. 19C, D). Valves lanceolate with prolonged, rostrate poles (Fig. 20B–J, see also Figs 23A, 24A, 25A), dimensions (n = 38): length 139–200 μm, width 6–8 μm at centre. Valve margins parallel near central area, gradually tapering towards rostrate poles (Fig. 20B–J). Sternum central, distinct, narrow, regular. Central area having three arrangements: extending towards both margins forming square to rectangular (Fig. 20B, J) or round hyaline space (Fig. 20C–E); extending to one margin with other margin flanked by few short striae (Fig. 20G–I); both margins bordered with few short striae (Fig. 20F). Ghost striae sometimes present (e.g., Fig. 20C, I) in central area. Striae parallel, radiate only at poles, and mostly opposite one another across sternum. Stria density 10–12 (often 11) in 10 μm.

Figure 19. 

Ulnaria jishou-biseriata sp. nov., ×400, LM A A cell in girdle view, note two long valve-appressed chloroplasts per cell B a dividing cell in girdle view, note the chloroplasts are distributed along the pervalvar axis C, D two cells in valve view, note the long plate of chloroplast. Scale bar: 20 μm.

Figure 20. 

Ulnaria jishou-biseriata sp. nov., ×630, LM A a frustule in girdle view, note the rectangle outline B–J nine valves exhibiting a size diminution series, note the lanceolate valve outline and the variable central areas D micrograph of holotype specimen. Scale bar: 20 μm.

SEM (Figs 21–25). In some dividing cells, both epivalve and hypovalve associated with valvocopula and two copulae, forming 3:3 configuration of girdle bands (Fig. 21A–F, bands labelled B1–B3, B1 = valvocopula); sometimes epivalve associated with valvocopula and three copulae, whereas hypovalve associated with valvocopula and two copulae, forming 4:3 configuration (Fig. 22A–D). Copulae sometimes bearing two rows of poroids near poles (Fig. 21C–F). Valvocopula a closed hoop, same shape as valve outline, closely attached to mantle interior, surrounding the valve internal margin (Fig. 23A); bearing a mostly continuous row of poroids dividing pars interior from pars exterior located at midline (Fig. 23B–E), some isolated poroids visible in pars exterior (Fig. 23B, two arrows). At the advalvar edge, valvocopula produces a row of serrated projections, each corresponding to a virga internally (Fig. 23C, arrows). Valvocopula lacking ornamentation at both poles (Fig. 23D, E, black arrow respectively). Striae continuing onto mantle, absent from centre (Fig. 24B). Valve face and mantle intersecting almost at a right angle (Fig. 24B–F). Valve characterized by relatively wide virgae, interconnected with thin viminules, and closing plates with few struts fixing them onto each areolar wall (Fig. 24C, D). Valve has two types of mixed striae: one composed of a biseriate main part and a uniseriate minor part near sternum (usually 1 or 2 areolae), which are distributed on most of the valve face except each apex, and the other composed of a uniseriate main part and a biseriate minor part, which are only present near each apex (Figs 24C, D, 25B–F). Ocellulimbus composed of ca. 18 pervalvar and 10 transverse rows of porelli (both pervalvar and transverse rows unequal in length). A few serrated apical outgrowths protruding over each ocellulimbus (Fig. 24C, three arrows). Internally, virgae transversely extending towards mantle from sternum. Striae situated almost opposite each other across sternum and becoming uniseriate near sternum (Fig. 25B–F). Central area with three arrangements: extending to one margin, bordering with several short striae (Figs 24B, external, 25E, internal); bordering both margins with several short striae (Figs 24E, external, 25F, internal); or extending to both margins forming transapically rectangular fascia (Figs 24F, external, 25B, internal). One rimoportula at each pole (Figs 23D, E, 24C, D, 25D), occasionally two produced at an apex (Fig. 25C). External opening of rimoportula expressed as a simple hole with different shapes (Fig. 24C, D); internally bilabiate, situated close to sternum, aligned with striae (Fig. 25C, D).

Figure 21. 

Ulnaria jishou-biseriata sp. nov., girdle view, SEM A a dividing cell in girdle view B middle detail from A, note the mantles are hyaline in the central area C, D two apical details from A, showing both epivalve and hypovalve with associated three girdle bands (labelled B1 to B3) E, F two other apical details also show both epivalve and hypovalve with associated three girdle bands in a dividing cell (labelled B1 to B3). Scale bars: 20 μm (A); 2 μm (B–F).

Figure 22. 

Ulnaria jishou-biseriata sp. nov., girdle view, SEM A a frustule B–D details from A, showing a 4:3 configuration of girdle bands in a dividing cell. Scale bars: 20 μm (A); 2 μm (B–D).

Figure 23. 

Ulnaria jishou-biseriata sp. nov., internal view, SEM A a valve with valvocopula B, C middle details from A, note serrated projections over each virga (C, arrows) D, E two apical details from A, note unornamented valvocopula at both apices (arrow respectively). Scale bars: 20 μm (A); 2 μm (B, D, E); 1 μm (C).

Figure 24. 

Ulnaria jishou-biseriata sp. nov., external view, SEM A a frustule in valve view B middle detail from A, showing central area flanked by a few marginal striae only on one side C, D two apical details from A, note a few serrated projections protruding over the ocellulimbus (C, three arrows) E a middle part showing the central area flanked by shortened striae on both sides F a middle part showing a rectangular central area. Scale bars: 20 μm (A); 2 μm (B, E, F); 1 μm (C, D).

Figure 25. 

Ulnaria jishou-biseriata sp. nov., internal view, SEM A a complete valve B middle detail from A, note the rectangular central area C apical detail from A, note two rimoportulae present D other apical detail from A, note only one rimoportula present E, F two middle parts, note the variable central areas. Scale bars: 20 μm (A); 2 μm (B–F).

The epithet jishou-biseriata is formed from the city name Jishou and the term biseriate to reflect its type locality (Jishou) and its mostly biseriate striae.

The sampling site is close to Jishou City and many anthropogenic influences affect the environment and hence the diatoms. The diatom samples were scraped off of the stone surfaces. The following environmental parameters were measured in the field: Conductivity was 202.3 ± 1.2 μS∙cm^-1, pH was 8.5 ± 0.1, and water temperature was 13.2 ± 0.3 °C. So far, its distribution is known only from the type locality. To sum up, U. jishou-biseriata lives on the stone surfaces of a mountainous river running through a small city.

Ulnaria jishou-biseriata is characterized by its lanceolate valve outline, mostly biseriate striae, and very variable central areas. With respect to the valve outline, it is similar in some ways to U. ulnabiseriata, but the former has smaller and very variable central areas whereas the latter’s central areas are always a rectangular fascia (see Liu et al. 2017, p 249, figs 30–35).

Slide JIUDIA202303, specimen circled on slide, illustrated as Fig. 26C.

PhycoBank http://phycobank.org/103809

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.

LM (Fig. 26). Valves panduriform with slightly constricted middle part and rostrate poles (Fig. 26A–P, see also Figs 27A, 28A, 29A). Valve dimensions (n = 36): length 37–60 μm, width 7–9.5 μm at centre, 8–10 μm at widest part. Sternum distinct, extending length of valve. Central area has two arrangements: an asymmetric hyaline region extending to both margins (Fig. 26A–M) or a hyaline area which extends to one margin with the other side bordered with a few short striae (Fig. 26N–P). Ghost striae are sometimes present (e.g., Fig. 26D, K) in the central area. Striae parallel, radiate only approaching each apex, and mostly opposite one another across sternum. Striae density 9–11 (often 10) in 10 μm.

Figure 26. 

Ulnaria pandurata-biseriata sp. nov., ×1000, LM A–P 16 valves exhibiting a size diminution series, note the panduriform valve outline and variable central areas C micrograph of holotype specimen. Scale bar: 10 μm.

Figure 27. 

Ulnaria pandurata-biseriata sp. nov., external view, SEM A a frustule in valve view B middle part detail from A, showing the central area with a few shortened marginal striae on one side C, D two apical details from A, note some partially triseriate striae (arrows) E another middle part showing the fascia-shaped central area F another apex, note a few serrated projections protruding over ocellulimbus. Scale bars: 10 μm (A); 2 μm (B–F).

Figure 28. 

Ulnaria pandurata-biseriata sp. nov., internal view, SEM A a complete valve B–D details from A, note some partially triseriate striae (arrows) E, F other apical details, note partially triseriate striae (arrows). Scale bars: 10 μm (A); 2 μm (B–F).

Figure 29. 

Ulnaria pandurata-biseriata sp. nov., internal view, SEM A a valve with a valvocopula B middle detail from A, note the unornamented middle portion of valvocopula (arrow) C, D apical details from A, note serrated projections over each virga (arrows) and valvocopula without ornamentation at each apex. Scale bars: 10 μm (A); 2 μm (B–D).

SEM (Figs 27–29). Valve characterized by relatively wide virgae, interconnected with thin viminules, areolar closing plates having a few struts fixing them onto the areolar wall (Figs 27A–F, 28A–F, 29A–D). Valve with two types of mixed striae: one composed of a biseriate main part and a uniseriate minor part near sternum (usually 1 or 2 areolae), which describe most striae of valve (Figs 27A–F, 28A–F), and the other composed of a biseriate part, a triseriate part, and a uniseriate part near sternum (usually 1 or 2 areolae) (Figs 27C, D, 28B–F, two arrows, respectively). One rimoportula present at each pole, externally expressed as a simple hole (Fig. 27C, D, F), internally bilabiate, situated close to sternum (Fig. 28C–F). Ocellulimbus composed of ca.19 pervalvar and 9 transverse rows of porelli. A few serrated apical outgrowths protruding over the ocellulimbus (Fig. 27F). Valvocopula is a closed hoop, attached to the mantle interior, surrounding internal valve margin (Fig. 29A). Each valvocopula bears a mostly continuous row of poroids dividing the pars interior from pars exterior, located at the midline (Fig. 29A–D); lacking ornamentation at either apex (Fig. 29C, D). On its advalvar edge, valvocopula bears a row of serrated projections, each corresponding internally to a virga (Fig. 29C, D, three arrows respectively).

The epithet pandurata-biseriata is a combination of the terms pandurate and biseriate to reflect the valvar panduriform outline of the valve and its mostly biseriate striae.

The sampling site is situated close to the headwaters of Jinbian stream, which originates in the Zhangjiajie National Forestry Park. The diatom samples were scraped off of stone surfaces. The following environmental parameters were measured in the field: Conductivity was 102.7 ± 0.8 μS∙cm^-1, pH was 8.5 ± 0.7 and water temperature was 8.7 ± 0.2 °C. So far, its distribution is known only from the type locality. To sum up, U. pandurata-biseriata lives on the stone surfaces of the headwaters of a mountainous stream.

Ulnaria pandurata-biseriata is characterized by its panduriform valve outline, mostly biseriate striae, variable central areas, and smaller valves. Similar taxa include U. goulardii D.M. Williams, Potapova & C.E. Wetzel (see Williams 1986, p. 141, figs 27–36) and U. sangzhi-biseriata sp. nov (see below). All possess mostly biseriate striae, but they can be distinguished by the panduriform valve outline of U. pandurata-biseriata from the two latter’s lanceolate valve outline (for U. goulardii, see Williams 1986, p. 141, figs 27–36, as Synedra goulardii).

Slide JIUDIA202304, specimen circled on slide, illustrated as Fig. 30C.

PhycoBank http://phycobank.org/103810.

China. Hunan province: Sangzhi County, Wudaoshui Town, Jinlong power station, Li River (29°43′7.1″N, 109°54′50.9″E, 398 m a.s.l.), collected by Bing Liu, September 30, 2015.

LM (Fig. 30). Valves linear-lanceolate with central margins sometimes very slightly constricted and capitate to sub-capitate apices (Fig. 30A–I, see also Figs 32A, E, 33A, 34A, E). Valve dimensions (n = 22): length 49–91 μm, width 6.5–8.2 μm at centre. Sternum discernible, extending length of valve. Central area rectangular or square. Ghost striae present in central area (e.g., Fig. 30B–D). Striae parallel, radiate only at poles, and mostly opposite each other across sternum. Stria density 10–12 (often 11) in 10 μm.

Figure 30. 

Ulnaria sangzhi-biseriata sp. nov., ×1000, LM A–I nine valves exhibiting a size diminution series, note linear-lanceolate valve outline, rectangular central area and capitate to sub-capitate apices C micrograph of holotype specimen. Scale bar: 10 μm.

SEM (Figs 31–34). Frustule rectangular in girdle view (Fig. 31A). Epivalve associated with valvocopula and three copulae (Fig. 31C, D, labelled B1–B4, B1 = valvocopula). Valvocopula is a closed hoop, attached to the mantle interior, surrounding the valve internal margin (Fig. 32A, E). The valvocopula has a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 26B–D). On its advalvar edge there is a row of serrated projections, each corresponding internally to a virga (Figs 31B, 32B–D, F, two arrowheads respectively), ornamentation is lacking at either pole (Fig. 32C, D, F). Valve face and mantle intersect almost at right angle (Fig. 33A–F). Central hyaline area rectangular or square (Figs 33B, E, 34B, F). Valve characterized by a series of relatively wide virgae, interconnected with thin viminules and closing plates affixed with a few struts to the areolar wall (Figs 32A–F, 33B–F, closing plate see Fig. 33F, two wavy arrows). Valve has two types of mixed striae: most striae of the valve are composed of a biseriate main part and a uniseriate minor part near the sternum (usually 1 or 2 areolae, Figs 33B–F, 34B–D, F), and the rest are composed of a biseriate part, a triseriate part, and a uniseriate part near sternum (usually 1 or 2 areolae) (Fig. 34C, D, two arrows respectively). Ocellulimbus composed of ca. 18 pervalvar and 7 transverse rows of porelli. A few serrated apical outgrowths protruding over each ocellulimbus (Fig. 33C, D, F, two arrows respectively). Striae continue onto mantle, absent in the centre (Fig. 31B). One rimoportula at each pole (Figs 33C, D, F, 34C, D), externally expressed as a simple hole in different shapes (Fig. 33C, D, F), internally bilabiate, situated close to sternum (Fig. 34C, D).

Figure 31. 

Ulnaria sangzhi-biseriata sp. nov., girdle view, SEM A a partly collapsed frustule B middle part from A, note variable central mantles and serrated projections of valvocopula (three arrowheads) C, D two apical details from A, showing four girdle bands associating the epivalve (labelled B1–B4). Scale bars: 10 μm (A); 2 μm (B–D).

Figure 32. 

Ulnaria sangzhi-biseriata sp. nov., internal view, SEM A a valve with a valvocopula B middle part from A, note the serrated projections (two arrowheads) C, D two apical details from A, note the closed nature of valvocopula and serrated projections (arrowheads) E another valve with a valvocopula F apical detail from E, note the serrated projections (two arrowheads). Scale bars: 10 μm (A, E); 2 μm (B–D, F).

Figure 33. 

Ulnaria sangzhi-biseriata sp. nov., external view, SEM A a complete valve B middle detail from A, note rectangular central area C, D two apical details from A, note a few serrated projections protruding over the ocellulimbus (arrows) E another middle part showing rectangular central area with ghost striae F another apical detail, note a few serrated projections (two arrows) and the closing plates (two curved arrows). Scale bars: 10 μm (A); 2 μm (B, E); 1 μm (C, D, F).

Figure 34. 

Ulnaria sangzhi-biseriata sp. nov., internal view, SEM A a complete valve B middle detail from A, showing the central area C, D two apical details from A, note part triseriate striae (arrows) E another complete valve F middle detail from E. Scale bars: 10 μm (A, E); 2 μm (B–D, F).

The epithet sangzhi-biseriata is a combination of Sangzi and the term biseriate to reflect its type locality (Sangzi) and its mostly biseriate striae.

The sampling site is near Wudaoshui Town, and some human activities may have affected the environment and hence the diatoms. The diatom samples were scraped off of the stone surfaces. The following environmental parameters were measured in the field: Conductivity was 219.3 ± 1.2 μS∙cm^-1, pH was 8.5 ± 0.2 and water temperature was 17.9 ± 0.3 °C. To sum up, U. sangzhi-biseriata lives on the stone surfaces of a mountainous river flowing away from the Town. So far, its distribution is known only from the type locality.

Ulnaria sangzhi-biseriata is characterized by its linear-lanceolate valve outline, mostly biseriate striae, rectangular or square central area, and capitate to sub-capitate apices. It is similar to U. goulardii which has a more constricted valve central margin. Moreover, the former has capitate to sub-capitate apices whereas U. goulardii has rostrate apices (see Williams 1986, p. 141, figs 27–36, as Synedra goulardii).

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

PhycoBank http://phycobank.org/103811

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.

LM (Fig. 35). Valves linear with abruptly tapering rostrate to sub-capitate apices (Fig. 35A–J, see also Figs 36A, E, 37A, E). 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), extending length of valve. Central area apically rectangular or trapezoid. Ghost striae sometimes present in central area (e.g., Fig. 35C, I). Striae parallel, radiate only at each pole, and mostly opposite across sternum. Stria density 10–11 in 10 μm.

Figure 35. 

Ulnaria wuling-biseriata, sp. nov., ×630, LM A–J ten valves exhibiting a size diminution series, note linear valve outlines, rostrate apices, and rectangular hyaline central area A micrograph of holotype specimen. Scale bar: 20 μm.

Figure 36. 

Ulnaria wuling-biseriata, sp. nov., external view, SEM A a complete valve B middle detail from A, showing the rectangular central area C, D two apical details of A, note some uniseriate striae at the apices E another complete valve F middle detail from E, showing a trapezoidal central area. Scale bars: 20 μm (A, E); 2 μm (B–D, F).

Figure 37. 

Ulnaria wuling-biseriata, sp. nov., internal view, SEM A a complete valve B middle detail from A, showing the rectangular central area C, D two apical details from A. E Another complete valve F middle detail from E showing the trapezoidal central area. Scale bars: 20 μm (A, E); 2 μm (B–D, F).

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

Figure 38. 

Ulnaria wuling-biseriata, sp. nov., internal view, SEM A a valve with a valvocopula B middle detail from A. C, D two apical details of A, note the valvocopula unornamented at each apex E, F details of the valvocopula, note its closed nature and the shelf-like projection (F, arrow). Scale bars: 20 μm (A); 2 μm (B–F).

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.

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.

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).

Slide JIUDIA202306, specimen circled on slide, illustrated as Fig. 39A.

PhycoBank http://phycobank.org/103812.

China. Qinghai province: Menyuan County, an unnamed river, at a sampling location named Kengtan (37°27'28"N, 101°23'15"E, 2940 m a.s.l.), collected by Bing Liu, July 18, 2019.

LM (Fig. 39). Valves lanceolate with rostrate to sub-capitate apices (Fig. 39A–M, see also Figs 40A, C, 41A, 42A). Valve dimensions (n = 24): length 104–236 μm, width 4.6–6.8 μm at centre. Sternum distinct, extending length of valve. Central area very variable: hyaline region extending to both margins forming rectangular fascia (e.g., Fig. 39A, see also Fig. 41B). It can be circumscribed by both short marginal striae and isolated areolae (e.g., Fig. 39D–F, see also Fig. 40D), nearly absent (Fig. 39J, see also Fig. 42B) or completely lacking (see Fig. 40A, B). Striae parallel, radiate only approaching each apex, some opposite each other, and others alternate across the sternum. Stria density 10–13 in 10 μm, increasing near each apex.

Figure 39. 

Ulnaria blancoi sp. nov., ×630, LM A–M thirteen valves exhibiting a size diminution series, note the lanceolate valve outline and small variable central areas A micrograph of holotype specimen. Scale bar: 20 μm.

Figure 40. 

Ulnaria blancoi sp. nov., external view, SEM A, C two complete valves, note central area present or absent B middle part from A, note central area completely absent D middle part from C, note small central area flanked by marginal short striae E, F two apical details, note two horn-like projections protruding over the ocellulimbus (E, two arrows). Scale bars: 20 μm (A, C); 2 μm (B, D, F); 1 μm (E).

Figure 41. 

Ulnaria blancoi sp. nov., internal view, SEM A a complete valve B middle part detail from A, note rectangular central area C, D two half parts from A. E, F Two apical details from A. Scale bars: 20 μm (A); 4 μm (B–D); 2 μm (E, F).

Figure 42. 

Ulnaria blancoi sp. nov., internal view, SEM A a complete valve B middle part from A, note the very small central area C, D other valve middle part details, note variable central areas. Scale bars: 20 μm (A); 2 μm (B–D).

SEM (Figs 40–43). Valve characterized by a series of relatively wide virgae, interconnected with vimines and closing plates attached with a few struts to each areolar wall (Figs 40A–F, 41A–F, 42A–D, closing plates see Fig. 43C). Striae uniseriate. Each stria on both sides opposite or alternate, areolae gradually apically elongated from sternum to mantle (Figs 40B, D, 41B, 42B–D). Central area completely lacking (Fig. 40A, B), hyaline region circumscribed by both short marginal striae and isolated areolae (Figs 40C, 42B–D), or hyaline area extending to both margins (Fig. 41B). Ocellulimbus composed of ca. 16 pervalvar and 7 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Fig. 40E, two arrows). One rimoportula located at each pole, externally expressed as a simple hole (Fig. 40E, F), internally bilabiate, situated close to sternum at an angle (Fig. 41E, F). Valvocopula a closed hoop, surrounding the valve internal margin (Fig. 43A). Valvocopula bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 43B–F), lacking ornamentation at both poles (Fig. 43E, F). On its advalvar edge, valvocopula has a row of serrated projections, each corresponding internally to a virga (Fig. 43B–E).

Figure 43. 

Ulnaria blancoi sp. nov., internal view, SEM A a valve with valvocopula B middle part detail from A. C Detail of valvocopula, note closing plates D–F apical details from A. Scale bars: 20 μm (A); 2 μm (B–F).

Named after the Spanish diatomist, Dr. Saúl Blanco.

The sampling site is located in the plateau which belongs to the highland continental climate zone. The diatom samples were scraped off of the stone surfaces. The following environmental parameters were measured in the field: Conductivity was 448.3 ± 0.5 μS∙cm^-1, pH was 8.3 ± 0.1 and water temperature was 11.9 ± 0.5 °C. To sum up, U. blancoi lives on the stone surfaces of a plateau river. So far, its distribution is known only from the type locality.

Ulnaria blancoi is characterized by its lanceolate valve outline, uniseriate striae, very variable central areas, and rostrate to sub-capitate apices. It differs from U. vitrea (Kützing) E. Reichardt by its much longer valves (104–236 μm vs 90–120 μm) and its often-present central area whereas U. vitrea often lacks central area (see Williams 2020, p. 4). Ulnaria splendens (Kützing) D.M. Williams et Van de Vijver is wider (5–10 μm vs 4.6–6.8 μm) and its stria density is lower than that of U. blancoi (6–10 striae in 10 μm vs 10–13 striae in 10 μm). Moreover, U. blancoi often has sub-capitate apices whereas U. splendens has rostrate apices (see Williams and Van de Vijver 2021, p. 167, figs 1–10).

Slide JIUDIA202307, specimen circled on slide, illustrated as Fig. 44D.

PhycoBank http://phycobank.org/103813

China. Qinghai province: Menyuan County, an unnamed river, at a sampling location named Kengtan (37°27'28"N, 101°23'15"E, 2940 m a.s.l.), collected by Bing Liu, July 18, 2019.

LM (Fig. 44). Valves lanceolate (fusiform) with cuneate to rostrate apices (Fig. 44A–J, see also Figs 45A, 46A). Valve dimensions (n = 31): length 60–104 μm, wide 5–7 μm at centre. Sternum distinct, extending length of valve. Central area not clearly visible due to presence of many ghost striae (Fig. 44A–J, see also Figs 45B, E, F, 46B, E, F). Striae parallel, radiate only approaching each pole, 12–14 in 10 μm, denser near poles. Striae on both sides of sternum, some alternate, some opposite.

Figure 44. 

Ulnaria menyuanensis sp. nov., ×1000, LM A–J ten valves exhibiting a size diminution series, note the lanceolate valve outline and distinctive ghost striae in the middle regions of the valves D micrograph of holotype specimen. Scale bar: 10 μm.

Figure 45. 

Ulnaria menyuanensis sp. nov., external view, SEM A a complete valve B middle part detail from A, note the shallow grooves and short striae at the central region C, D two apical details from A. E, F Other middle parts, note the shallow grooves and short striae. Scale bars: 10 μm (A); 2 μm (B–F).

SEM (Figs 45–47). Valve characterized by a series of relatively wide virgae, interconnected with vimines and closing plates affixed with a few struts to each areolar wall (Figs 45A–F, 46A–F, closing plate see Fig. 47D, F). Central area circumscribed by both short marginal striae and isolated areolae (Figs 45B, E, F, 46B, E, F). Unperforate internal shallow grooves distinct in central area (e.g., Fig. 46B, E, F). Ocellulimbus composed of ca. 13 pervalvar and 7 transverse rows of porelli. Striae uniseriate. Areolae not apically elongated from sternum to mantle (Fig. 46B–F). One rimoportula located at each pole, externally expressed as a simple hole (Fig. 45C, D), internally bilabiate, situated close to sternum (Fig. 46C, D). Valvocopula a closed hoop, surrounding the valve internal margin (Fig. 47A). Valvocopula bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at midline (Fig. 47B, C, E), lacking ornamentation at both poles (Fig. 47D, F). On its advalvar edge, valvocopula has a row of serrated projections, each corresponding internally to a virga (Fig. 47B, C, E, three arrows, respectively).

Figure 46. 

Ulnaria menyuanensis sp. nov., internal view, SEM A a complete valve B middle part from A, note shallow grooves and short striae C, D two apical details from A, note the bilabiate rimoportulae and apical pore fields E, F other middle parts, note shallow grooves and short striae. Scale bars: 10 μm (A); 2 μm (B–F).

Figure 47. 

Ulnaria menyuanensis sp. nov., internal view, SEM A a valve with associated valvocopula B middle part detail from A, note serrated projections (three arrows) C, D apical details from A, note serrated projections (C, three arrows) and closing plates (D, two arrows) E, F details from other apex from A, note serrated projections (E, three arrows) and closing plates (F, two arrows). Scale bars: 10 μm (A); 5 μm (B, C, E); 2 μm (D, F).

Named after Menyuan County, where the species was found.

Ulnaria menyuanensis was commonly found in the surface sediment collected in Kengtan with U. blancoi. Thus, U. menyuanensis lives on the stone surfaces of a plateau river. So far, its distribution is known only from the type locality.

Ulnaria menyuanensis is characterized by its fusiform valve outline, the presence of distinct ghost striae, and cuneate to rostrate apices. It differs from U. ramesii (Héribaud) T. Ohtsuka by the latter’s linear-lanceolate valve outline (see Morales et al. 2007, p. 73, figs 87–94, as Synedra ulna var. ramesi) and differs from U. oxyrhynchus (Kützing) Aboal by the latter’s acute apices (see Morales et al. 2007, p. 65, figs 62–67, as Synedra ulna var. oxyrhynchus). Ulnaria verhaegeniana Van de Vijver, De Haan, Mertens & Cocquyt has parallel margins almost to valve apices while U. menyuanensis has lanceolate valve outline and possesses distinct ghost striae (see Van de Vijver et al. 2017, p. 222 for comparison).

Slide JIUDIA202308, specimen circled on slide, illustrated as Fig. 48A.

PhycoBank http://phycobank.org/103814.

China. Qinghai province: Menyuan County, an unnamed river, at a sampling location named Kengtan (37°27'28"N, 101°23'15"E, 2940 m a.s.l.), collected by Bing Liu, July 18, 2019.

LM (Fig. 48). Valves linear-lanceolate with distinct capitate apices (Fig. 48A–K, see also Figs 49A, 50A). Valve dimensions (n = 23): length 202–307 μm, width 4.5–6.7 μm at centre. Sternum distinct, extending length of valve. Central area very variable: hyaline region extending to both margins (e.g., Fig. 48F, K), can be circumscribed by both short marginal striae and isolated areolae (e.g., Fig. 48B, C, G, J), nearly absent (Fig. 48H) or completely lacking (Fig. 48A, D, E, I). Striae parallel, radiate only approaching each pole, 9–11 in 10 μm, increasing near each pole. Striae on both sides of sternum, some opposite each other, and others alternate.

Figure 48. 

Ulnaria neobiceps sp. nov., ×400, LM A–K eleven valves exhibiting a size diminution series, note the linear-lanceolate valve outline and variable central areas A micrograph of holotype specimen. Scale bar: 20 μm.

Figure 49. 

Ulnaria neobiceps sp. nov., external view, SEM A a complete valve B middle part detail from A, note central area complete absent C–F apical details from A, note the capitate apices. Scale bars: 20 μm (A); 2 μm (B); 3 μm (C–E); 1 μm (F).

Figure 50. 

Ulnaria neobiceps sp. nov., internal view, SEM A a complete valve B middle part detail from A, note the very small central area (arrow) C, E two poles from A, note that valve margins do not constrict near the capitate apices (two arrows, respectively) D, F two apical details, note the capitate apices and apical pore field. Scale bars: 20 μm (A); 2 μm (B–F).

SEM (Figs 49–53). Valve characterized by a series of relatively wide virgae and interconnected with vimines (Fig. 49B–F). Central area completely lacking (Fig. 49B), hyaline area circumscribed by both short marginal striae and isolated areolae (Figs 50B, 51A, C, D), or hyaline area extending to both margins (Fig. 51B). Striae uniseriate, on both sides of sternum, opposite or alternate, areolae gradually become elongated from sternum to mantle (Figs 50B–F, 51A–D). Ocellulimbus composed of ca. 24 pervalvar and 8 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Fig. 52D, two arrows). One rimoportula located at each pole, externally expressed as a simple hole (Fig. 49F), internally bilabiate, situated close to sternum at an angle (Fig. 50D, F). Valvocopula closed, surrounding the valve internal margin (Fig. 52A), bearing a mostly continuous midline row of poroids dividing pars interior from pars exterior (Figs 52B–F, 53A–F), lacking ornamentation at both poles (Figs 52D, F, 52C–F). On its advalvar edge, valvocopula has a row of serrated projections, each corresponding internally to a virga (Fig. 52B, C, E). Shelf-like projections present at pars interior of each apex (Fig. 53C–F, two arrows, respectively).

Figure 51. 

Ulnaria neobiceps sp. nov., internal view, SEM A–D four middle valve parts showing very variable central areas. Scale bars: 2 μm (A–D).

Figure 52. 

Ulnaria neobiceps sp. nov., internal view, SEM A a valve with valvocopula B–F details from A, showing the valvocopula structure, note two horn-like projections protruding over ocellulimbus. Scale bars: 20 μm (A); 3 μm (B, C, E); 2 μm (D, F).

Figure 53. 

Ulnaria neobiceps sp. nov., valvocopula, SEM A a complete valvocopula B–D details from A, showing row of poroids interrupted in the middle and shelf-like projection at each apex (C, D, two arrows respectively) E, F other two apical details of valvocopula have the same apical structure. Scale bars: 20 μm (A); 3 μm (B); 2 μm (C–F).

The epithet biceps has been occupied by Ulnaria biceps (Kützing) Compère, so here the epithet neobiceps is used, which is a combination of neo (new) and biceps (two capitate) reflecting its two distinctly capitate poles.

Ulnaria neobiceps, U. blancoi, and U. menyuanensis were commonly found in the same sampling site of Kengtan. Thus, U. neobiceps lives on the stone surfaces of a plateau river. So far, its distribution is known only from the type locality.

Ulnaria neobiceps is characterized by its linear-lanceolate valve outline, variable central area, distinctly capitate apices, and long and slender valve. Both U. neobiceps and U. capitata (Ehrenberg) Compère have capitate apices, but the apices of U. capitata are rhomboid-capitate (see Morales et al. 2007, p. 49, figs 13–17; p. 51, figs 18–20, as Synedra capitata) whereas the apices of U. neobiceps are rounded-capitate. Moreover, U. neobiceps has very variable central area while U. capitata lacks central area.

Slide JIUDIA202309, specimen circled on slide, illustrated as Fig. 54A.

PhycoBank http://phycobank.org/103815.

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.

LM (Fig. 54). Valves linear with rostrate apices (Fig. 54A–P, see also Figs 55E, 56A–C). Valve dimensions (n = 51): length 42–66 μm, width 6–8 μm at centre. Sternum distinct, extending length of valve. Central area not clearly visible due to presence of ghost striae (Fig. 54A–G, I–K, M) or completely lacking (Fig. 54H, L, N–P). Striae parallel, radiate only approaching each pole, 12–15 in 10 μm. Across sternum some striae opposite one another, others alternate.

Figure 54. 

Ulnaria chengduoensis sp. nov., ×1000, LM A–P sixteen valves exhibiting a size diminution series, note the linear-lanceolate valve outline and variable central areas A micrograph of holotype specimen. Scale bar: 10 μm.

SEM (Figs 55, 56). Valve characterized by a series of relatively wide virgae, interconnected with vimines (Fig. 55B–D). Striae uniseriate, areolae often apically elongated (Fig. 56E). Central area variable: a hyaline area circumscribed by both short marginal striae and isolated areolae (Figs 55B, 56A, B), or completely absent (Figs 55F, 56E). One rimoportula located at each pole, externally expressed as a simple hole (Fig. 55C, D), internally bilabiate, situated close to sternum (Fig. 56D, F). Ocellulimbus composed of ca. 12 pervalvar and 9 transverse rows of porelli (Fig. 56F).

Figure 55. 

Ulnaria chengduoensis sp. nov., external view, SEM A a broken valve B middle part detail from A, note the central area flanked by marginal short striae C, D two apical details from A, note the rostrate apices E a complete valve F middle part detail from E, note central area absent. Scale bars: 10 μm (A, E); 2 μm (B–D, F).

Figure 56. 

Ulnaria chengduoensis sp. nov., internal view, SEM A–C three complete valves, note the linear-lanceolate valve outlines and variable central areas D–F details from C, note rostrate apices and absent central area. Scale bars: 10 μm (A–C); 2 μm (D, E); 1 μm (F).

Named after Chengduo County, where this species was found.

Epilithic in a plateau river. The following environmental parameters were measured in the field: Conductivity was 422.7 ± 1.3 μS∙cm^-1, pH was 8.2 ± 0.1 and water temperature was 12.2 ± 0.5 °C. So far, its distribution is known only from the type locality.

Ulnaria chengduoensis is characterized by its linear valve outline, variable central area, narrow rostrate valve apices. It differs from U. ramerii and U. verhaegeniana by its variable central area, i.e., it may completely lack a central area whereas U. ramerii always possesses an ellipsoid to rectangular central area (see Morales et al. 2007, p. 73, figs 87–94, as Synedra ulna var. ramesi) and U. verhaegeniana always has a large, apically elongated, rectangular central area (see Van de Vijver et al. 2017, p. 223, figs 1–13).

Slide JIUDIA202310, specimen circled on slide, illustrated as Fig. 57C.

PhycoBank http://phycobank.org/103816.

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.

LM (Fig. 57). Frustule rectangular in girdle view (Fig. 57A). Valves linear-lanceolate with sub-capitate apices (Fig. 57B–N, see also Figs 58A, 59A). 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.

Figure 57. 

Ulnaria qinghainensis sp. nov., ×630, LM A a frustule in girdle view B–N thirteen valves exhibiting a size diminution series, note the narrowly lanceolate valve outlines and absent central areas B micrograph of holotype specimen. Scale bar: 20 μm.

Figure 58. 

Ulnaria qinghainensis sp. nov., external view, SEM A a valve with valvocopula B detail of middle part from A, note absent central area C–F two poles from A, note two horn-like projections (D, two arrows) and row of poroids terminating before each apex of valvocopula (E, F, wavy arrow respectively). Scale bars: 20 μm (A); 4 μm (B–F).

SEM (Figs 58–60). Valve characterized by a series of relatively wide virgae, interconnected with vimines (Fig. 58B–F). Striae uniseriate. Stria mostly opposite across sternum, equidistant until radiate at poles, areolae often apically elongated, especially near the mantle (Figs 58B–F, 59B, C, E). Central area completely absent (Figs 58B, 59B). Ocellulimbus composed of ca. 18 pervalvar and 9 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Fig. 58D, two arrows). One rimoportula located at each pole, externally expressed as a simple hole (Fig. 58D, F), internally bilabiate, situated close to sternum (Fig. 59D, F). Valvocopula closed, surrounding the valve internal margin (Fig. 60A), bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 60B–F), lacking ornamentation at both poles (Fig. 60D, F). On its advalvar edge, valvocopula has a row of serrated projections, each corresponding internally to a virga (Fig. 60B, C, E).

Figure 59. 

Ulnaria qinghainensis sp. nov., internal view, SEM A a complete valve B middle part from A, note central area is absent C–F two apical details from A. Scale bars: 20 μm (A); 4 μm (B, C, E); 1 μm (D, F).

Figure 60. 

Ulnaria qinghainensis sp. nov., internal view, SEM A valve with valvocopula B middle part from A. C–F Two apical details from A. Scale bars: 20 μm (A); 4 μm (B, C, E); 1 μm (D, F).

Named after Qinghai province, where this species was found.

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.

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).

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

PhycoBank http://phycobank.org/103817.

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.

LM (Figs 61, 62). Living cells with numerous plate-like chromatophores (Fig. 61A–F, note that these cells may be in an unhealthy condition). Valves lanceolate, narrow, with rostrate to sub-capitate apices (Figs 61E, F, 62A–N). 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.

Figure 61. 

Ulnaria fanjingensis sp. nov., ×400, LM A–D living cells in girdle view, note numerous plate-like chromatophores E, F two living cells in valve view, note numerous plate-like chromatophores. Scale bar: 20 μm.

Figure 62. 

Ulnaria fanjingensis sp. nov., ×400, LM A–N fourteen valves exhibiting a size diminution series, note the lanceolate valve outline and hyaline central area C micrograph of holotype specimen. Scale bar: 20 μm.

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

Figure 63. 

Ulnaria fanjingensis sp. nov., girdle view, SEM. A a frustule in girdle view B–D details from A, note the 3:2 configuration of girdle bands E, F apical details from D, showing the closing plates (two arrows respectively) and two horn-like projections (F, two arrowheads). Scale bars: 20 μm (A); 2 μm (B–D); 1 μm (E, F).

Figure 64. 

Ulnaria fanjingensis sp. nov., internal view, SEM. A a valve with valvocopula B detail from A, note the row of poroids interrupted in the middle (two arrows) C, D details from A. E, F Two apical details from A. Scale bars: 20 μm (A), 4 μm (B–D), 1 μm (E, F).

Figure 65. 

Ulnaria fanjingensis sp. nov., external view, SEM A a complete valve B middle detail from A, showing the clear central area C middle detail of another valve showing the central area D a pole from A, note the slightly radiated striae and sub-capitate apex E, F two apices from A, note two largest horn-like projections and ocellulimbus. Scale bars: 20 μm (A); 2 μm (B–D); 1 μm (E, F).

Figure 66. 

Ulnaria fanjingensis sp. nov., internal view, SEM A a complete valve B middle part detail from A, note the clear central area C detail of another valve center showing the clear central area D a pole from A, note the tapering valve and rostrate apex E, F two apical details from A, note bilabiate rimoportulae and rostrate apices. Scale bars: 20 μm (A); 5 μm (B–D); 1 μm (E, F).

Named after Fanjing Mountain, where the species was found.

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.

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).

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

PhycoBank http://phycobank.org/103818.

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.

LM (Figs 67, 68). Living cells with numerous discoid chromatophores (Fig. 67A–E, note that these cells may be in an unhealthy condition). Frustule in girdle view rectangular (Figs 67A–C, 68A, see also Fig. 69A). Valves lanceolate with protracted, rostrate to sub-capitate poles (Figs 67D, E, 68B–M, see also Figs 70A, 71A, 72A). 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.

Figure 67. 

Ulnaria hupingensis sp. nov., ×630, LM A–C living cells in girdle view, note numerous irregular chromatophores D, E two living cells in valve view, note numerous discoid chromatophores. Scale bar: 20 μm.

Figure 68. 

Ulnaria hupingensis sp. nov., ×630, LM. A a frustule in girdle view B–M twelve valves exhibiting a size diminution series, note the lanceolate valve outline and completely absent central area B micrograph of holotype specimen. Scale bar: 20 μm.

SEM (Figs 69–72). Frustule comprising several girdle bands (Fig. 69A–F). Epivalve associated with valvocopula and two copulae (Fig. 69D, 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), bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at midline (Fig. 70B–F), poroids lacking at centre of the valve (Fig. 70B, two arrows). On its advalvar edge, valvocopula bears a row of serrated projections, each corresponding to a virga internally (Fig. 70C, E, three arrows, respectively). Valvocopula lacking ornamentation at both poles (Fig. 70D, F). Valve face and mantle intersecting almost at right angle (Fig. 71A, B). 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). Striae uniseriate (Figs 71B, 72B–E), continuing onto mantle (Fig. 69B–F). Ocellulimbus composed of ca. 19 pervalvar and 11 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Figs 69F, 71C–F, 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). Central area completely lacking (Figs 71A, B, external, 72A, B, internal). One rimoportula usually present at each pole, occasionally two produced at one end (Figs 70D, two arrows, 71D). External opening of rimoportula expresses as a simple hole, forming different shapes (Fig. 71C–F); internally bilabiate, situated close to sternum at an angle (Fig. 72D–F).

Figure 69. 

Ulnaria hupingensis sp. nov., girdle view, SEM A a frustule in girdle view B–E details from A, note three copulae (labelled B1 to B3) associated with the epivalve F apical detail from E, showing two horn-like projections (two arrows respectively). Scale bars: 20 μm (A); 2 μm (B–F).

Figure 70. 

Ulnaria hupingensis sp. nov., internal view, SEM A a valve with valvocopula B middle detail from A, note the row of poroids interrupted in the middle (two arrows) C, E two poles from A. D Apical detail from C, note two rimoportulae at one apex (two arrows) F apical detail from E, note one rimoportula at one apex. Scale bars: 20 μm (A); 2 μm (B–F).

Figure 71. 

Ulnaria hupingensis sp. nov., external view, SEM A a complete valve B middle part detail from A, note central area complete absent C, D two apical details from A, showing two horn-like projections protruding over the oceullulimbus (two arrows, respectively) E, F two other apical details showing two horn-like projections protruding over the ocellulimbus (two arrows, respectively). Scale bars: 20 μm (A); 1 μm (B–F).

Figure 72. 

Ulnaria hupingensis sp. nov., internal view, SEM A a complete valve B, C middle part details from A, note central area is completely absent D–F apical details from A. Scale bars: 20 μm (A); 2 μm (B–F).

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

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.

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).

Slide JIUDIA202313, specimen circled on slide, illustrated as Fig. 73A.

PhycoBank http://phycobank.org/103819.

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.

LM (Figs 73). Valves generally linear (i.e., valve margins almost parallel), slightly undulate in larger specimens (Fig. 73A–C, see also Fig. 76B, C), parallel in smaller specimens (Fig. 73D–H, see also Figs 74A, 75A, 76A). Valve tapers towards apex, then it is protracted to broadly rostrate poles. Valve dimensions (n = 33): length 64–120 μm, width 6.0–8.6 μm at centre. Sternum distinct, extending length of valve. Central area completely absent. Striae parallel, radiate only approaching each pole, and mostly opposite one another across sternum. Stria density 10.5–12 (often 11) in 10 μm.

Figure 73. 

Ulnaria xieriverensis sp. nov., ×1000, LM A–H eight valves exhibiting a size diminution series, note the almost parallel but slightly undulate valve margins in larger specimens (A–C) and parallel valve margins in smaller specimens (D–H). A Micrograph of holotype specimen. Scale bar: 10 μm.

SEM (Figs 69–72). Valve characterized by relatively wide virgae, interconnected with vimines, closing plates affixed with a few struts to the areolar wall (Fig. 74B–D). Ocellulimbus composed of ca. 16 pervalvar and 9 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Fig. 74E, F, two arrows, respectively). Striae uniseriate. Stria situated opposite each other across sternum, equidistant until radiate at poles, areolae become elongated closer to the mantle (Fig. 75B–F). One rimoportula present at each pole, externally expressed as a simple hole (Fig. 74C–F), internally bilabiate, situated close to sternum (Fig. 75C, E, F), sometimes displaced, against mantle (Fig. 75D). Central area completely lacking (Figs 74A, B, 75A, B, 76A–D). Valvocopula a closed hoop (Fig. 76A–C). Valvocopula bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 76D–F), lacking ornamentation at both poles (Fig. 76E, F). On its advalvar edge, valvocopula has a row of serrated projections, each corresponding internally to a virga (Fig. 76D, E, three arrows, respectively).

Figure 74. 

Ulnaria xieriverensis sp. nov., external view, SEM A a complete valve B middle part detail from A, note central area is completely absent C, D two apical details from A. E, F Two other apical details, note two horn-like projections protruding over the ocellulimbus (two arrows respectively). Scale bars: 10 μm (A); 1 μm (B–F).

Figure 75. 

Ulnaria xieriverensis sp. nov., internal view, SEM A a complete valve B middle part detail from A, note central area is completely absent C, D two apical details from A, note one rimoportula located against the mantle (D, arrow) E, F two other apical details. Scale bars: 10 μm (A); 1 μm (B–F).

Figure 76. 

Ulnaria xieriverensis sp. nov., internal view, SEM A a complete valve with valvocopula B, C two complete valves with valvocopula, note undulate valve margins D middle detail from A, note the central area is completely absent and a row of serrated projections over virgae (three arrows) E, F two apical details from A, note serrated projections over virgae (E, three arrows). Scale bars: 10 μm (A–C); 1 μm (D–F).

Named after Xie River, where the species was found.

Epilithic in a mountain stream with oligotrophic waters. Ulnaria hupingensis was found in the same sampling site with U. xieriverensis and the environmental parameters see above. So far, its distribution is known only from the type locality.

Ulnaria xieriverensis is characterized by its linear valve outline, absence of central area, and rostrate apices. It differs from U. hupingensis by its linear valve outline.

Slide JIUDIA202314, specimen circled on slide, illustrated as Fig. 77C.

PhycoBank http://phycobank.org/103820.

China. Hunan province: Lanshan County, Shun River, a sampling location (25°11'29"N, 112°7'47"E, 490 m a.s.l.), collected by Bing Liu, October 5, 2021.

LM (Figs 77). Valves panduriform with protracted, rostrate apices (Fig. 77A–J, see also Figs 78A, B, 79A, B, 80A, B). Valve dimensions (n = 28): length 70–116 μm, width 6.2–8.2 μm at centre. Sternum distinct, extending length of the valve. Central area distinct, rectangular fascia. Striae parallel, radiate only approaching each apex, and mostly opposite across sternum. Stria density 9–11 in 10 μm.

Figure 77. 

Ulnaria pandurata-uniseriata sp. nov., ×1000, LM A–J ten valves exhibiting a size diminution series, note the panduriform valve outline C micrograph of holotype specimen. Scale bar: 10 μm.

Figure 78. 

Ulnaria pandurata-uniseriata sp. nov., external view, SEM A, B two complete valves, note panduriform valve outline C, D two middle part details from A, B, respectively, note rectangular central areas E, F two apical details from B, note two horn-like projections protruding over ocellulimbus. Scale bars: 10 μm (A, B); 1 μm (C, D); 2 μm (E, F).

Figure 79. 

Ulnaria pandurata-uniseriata sp. nov., internal view, SEM A, B two complete valves, note panduriform valve outline. C, D middle part details from A, B, respectively, note constricted central parts E, F two apical details from B. Scale bars: 10 μm (A, B); 1 μm (C, D); 2 μm (E, F).

SEM (Figs 78–80). Valve characterized by relatively wide virgae, interconnected with vimines (Fig. 78A–D). Ocellulimbus composed of ca. 17 pervalvar and 8 transverse rows of porelli. Two horn-like projections protruding over the ocellulimbus (Fig. 78E, F). Striae uniseriate, situated opposite each other across sternum, equidistant until radiate at poles, areolae become elongated closer to the mantle (Figs 78C, D, 79C, D). One rimoportula present at each pole, externally expressed as a simple hole (Fig. 78E, F), internally bilabiate, situated close to sternum (Figs 79E, F, 80E, F). Central area rectangular hyaline region (Figs 78C, D, 79C, D). Valvocopula a closed hoop, surrounding the valve internal margin (Fig. 80A, B), bearing a mostly continuous row of poroids dividing pars interior from pars exterior, located at the midline (Fig. 80B, D–F), lacking ornamentation at both poles (Fig. 80E, F). On its advalvar edge, valvocopula has a row of serrated projections, each corresponding internally to a virga (Fig. 80B, D–F).

Figure 80. 

Ulnaria pandurata-uniseriata sp. nov., internal view, SEM A, B two complete valves with valvocopula C, D two middle details from A, B, respectively E, F two apical details from B. Scale bars: 10 μm (A, B); 2 μm (C–F).

The epithet pandurata>-uniseriata is a combination of the terms pandurate and uniseriate reflecting the panduriform outline of the valve and its mostly uniseriate striae.

Epilithic in a mountain stream with oligotrophic waters. The following environmental parameters were measured in the field: Conductivity was 53.9 ± 0.6 μS∙cm^-1, pH was 8.4 ± 0.3 and water temperature was 21.9 ± 0.1 °C. So far, its distribution is known only from the type locality.

Ulnaria pandurata-uniseriata is characterized by its panduriform valve outline, rectangular central area, mostly uniseriate striae, and its rostrate apices. It differs from U. jumlensis (Jüttner) D.M. Williams & Karthick by its narrower valve (6.2–8.2 μm vs 7.5–11.2 μm) and lower stria density (9–11 in 10 μm vs 13–14 in 10 μm) (see Jüttner et al. 2000, p. 249).