Oricymba sinensis Bing Liu &amp; Rioual 2023, sp. nov.
Creators: name: Yuan, Li
name: Liu, Bing
name: Rioual, Patrick
name: Yi, Man-Qi
name: Zheng, Yan
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Chromista
Ochrophyta
Bacillariophyceae
Cymbellales
Cymbellaceae
Oricymba
Oricymba sinensis

description: <i>Oricymba sinensis</i> Bing Liu &amp; Rioual <i>sp. nov.</i> (LM: Figs 1–15, SEM: Figs 16–39) <b>Description:—</b> LM: Valves dorsiventral possessing arcuate dorsal margin and slightly convex to straight ventral margin (Figs 1–15). Apices not protracted or occasionally slightly protracted, bluntly rounded. Valve dimensions (n = 31): 36–52 μm long, 7.8–10.1 μm wide, length/width ratio range 4.2–5.5, median 4.9. Axial area narrow, lanceolate, expanded at central area. Raphe filiform. Proximal raphe endings deflected towards ventral side (primary side). Central pores present. Central area asymmetrical, occupying c. 1/3 of the valve width, flanked by c. 4 shortened ventral striae. A stigma evident on ventral side of valve. Striae radiate throughout valve, 9–11 in 10 μm in central portion of dorsal side, 9–12 in 10 μm in central portion of ventral side. Areolae difficult to resolve under LM. SEM, external view: Valves asymmetric along apical axis, proximal raphe endings bent towards ventral side, and distal raphe fissures deflected towards dorsal side (Figs 16, 22, 28). Marginal ridge evident along dorsal valve margin (Figs 16–18, 20, black arrows, see also Figs 22–24, 26) whereas marginal ridge inconspicuous along the ventral margin (Figs 28–30, 32, black arrows). External openings of areolae slit-like except those adjacent to axial area, which are curved or lunate (Figs 23, 24, 26, arrows). Dentate projections produced under each external opening of areola. Areola density 30–35 in 10 μm. Shallow depressions present in axial and central area (Fig. 17, white arrows). Apical pore field forming a continuous area, not divided by distal raphe fissure, clearly separated from areolae (Figs 19, 21), composed of c. 5–8 transapical rows and 15–17 pervalvar rows. Foramina of apical pore field mostly rounded but a few top foramina elongate (Figs 25, 27, 31, 33, arrows). A notch present on dorsal side of distal raphe fissure (Figs 19, 21, 31, 33, wavy arrows, respectively). Valve mantle deep, meeting valve face at a right angle. Striae continuing onto valve mantle, but terminated before mid-line of valve mantle, such that abvalvar part of mantle without ornaments (Figs 20, 21, 29, 30, 32, double-headed arrows, respectively). Girdle bands simple, c. three copulae per cell (Fig. 21). SEM, internal view: Valve asymmetric along apical axis, raphe straight, almost along valve mid-line, virgae and depressed striae alternate throughout valve (Fig. 34). Proximal raphe endings not visible because obscured by flap above central nodule (Fig. 35, two wavy arrows) and distal raphe ends terminating in knob-like helictoglossae. Internally, stigma having two slit-like openings with fine ingrowths from perimeter (Fig. 35, two arrows). Areola internal openings occluded by dentate projections (Figs 35, 36, 38). Apical pore field clearly separated from other parts of valve (Fig. 37, two arrows). An undulate flap-like silica strip covering internal apertures of each pervalvar row of foramina, not completely occluding internal apertures (Fig. 39, two arrows). <b>Type:—</b> CHINA. Hunan province: Jianghua County, a sampling point from a headwater stream that runs into the Xiao River (25°4′24″ N, 111°50′54″ E, 380 m asl), <i> Bing Liu, October 4 th 2021</i> (holotype JIU! Slide DIA202201, specimen circled on slide = Fig. 1). Registration: http://phycobank.org/103643. <b>Etymology:—</b> Named after China where the species was found. <b>Ecology:—</b> Inhabiting surfaces of submerged stones, thus, belonging to river epilithon. In fresh waters, detailed information in Table 1. This species was associated with <i>Amphipleura vavilovii</i> Glushchenko &amp; Kulikovskiy (2017: 17), and several unidentified species of <i>Fragilaria</i> Lyngbye (1819: 182), <i>Navicula</i> Bory (1822: 128), <i>Cymbella</i> Agardh (1830: 1) and <i>Gomphonema</i> Ehrenberg (1832: 87).
description: Published as part of <i>Yuan, Li, Liu, Bing, Rioual, Patrick, Yi, Man-Qi &amp; Zheng, Yan, 2023, Two new species of Oricymba (Bacillariophyta) from China, described with reference to the structure of the apical pore field, pp. 181-195 in Phytotaxa 591 (3)</i> on pages 183-188, DOI: 10.11646/phytotaxa.591.3.1, http://zenodo.org/record/7800808
description: {"references": ["Glushchenko, A. M. &amp; Kulikovskiy, M. S. (2017) Amphipleura vavilovii: A new diatom species of the family Amphipleuraceae from Laos [J]. Inland Water Biology 10 (1): 17 - 21. https: // doi. org / 10.1134 / S 1995082916040064", "Lyngbye, H. C. (1819) Tentamen Hydrophytologiae Danicae Continens omnia Hydrophyta Cryptogama Daniae, Holsatiae, Faeroae, Islandiae, Groenlandiae hucusque cognita, Systematice Disposita, Descripta et iconibus illustrata, Adjectis Simul Speciebus Norvegicis. Hafniae, Typis Schultzianis, in commissis Librariae Gyldendaliae, Copenhague, 248 pp.", "Bory de Saint-Vincent, J. B. G. M. (1822) Bacillariees. Dictionnaire Classique d'Histoire naturelle 2: 127 - 129.", "Agardh, C. A. (1830) Conspectus criticus diatomacearum. Part 1. Litteris Berlingianis, Lund, 16 pp.", "Ehrenberg, C. G. (1832) Uber die Entwickelung und Lebensdauer der Infusionsthiere; nebst ferneren Beitragen zu einer Vergleichung ihrer organischen Systeme. Abhandlungen der Koniglichen Akademie Wissenschaften zu Berlin, Physikalische Klasse, pp. 1 - 154."]}