Ulnaria ulnabiseriata D. M. Williams et Bing Liu 2017, sp. nov.
Creators: name: Liu, Bing
name: Williams, David M.
name: Tan, Lin
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Chromista
Ochrophyta
Bacillariophyceae
Fragilariales
Fragilariaceae
Ulnaria
Ulnaria ulnabiseriata

description: Ulnaria ulnabiseriata D.M. Williams et Bing Liu, sp. nov. (Figs 30–51)   
LM: Frustules rectangular in girdle view (Fig. 36). Valves linear-lanceolate with protracted subcapitate to rostrate poles (Figs 30–35). Valves with parallel sides at the centre, slightly tapering towards the poles from c. 1/3 down each half of the valve (Figs 30–35). Transapical axis 6–8 μm, apical axis 105–229 μm (n = 50). Sternum central, distinctive, regular, extending length of valve. Striae broad, parallel, radiating only at poles, 9–11(often 10) in 10 μm. With respect to sternum, striae mostly opposite one another, few deviating, mostly, but not always, towards the poles (Figs 30–35, arrows). A single rimoportula at each pole, central area rectangular, c. 8×10 μm.  
SEM: Frustules rectangular in girdle view, epivalve with valvocopula and three copulae (Figs 37–40, B 8–B5), as for hypovalve (Figs 37–40, B 1–B 4). Each band possessing a single row of poroids which bisects the pars interior and exterior, located at mid-line of each girdle band (Figs 38–40). Valve face and mantle meet almost at right angles (Figs 37–40). Valves with biseriate striae, situated opposite each other, equidistant until radiating at poles; striae extending to valve face-mantle junction then continued onto mantle (Figs 37–40, 42–46). Each stria formed from externally raised virgae with vimines, the latter having closing plates producing biseriate structure (Figs 44–46). Each areola (including those on mantle) covered externally by velum (Fig. 47). A single rimoportula present at each pole, each a pair of simple extended lips, situated close to sternum (Figs 42–43). Two horn-like outgrowths located on top of each ocellulimbus (Figs 38, 40, 47). Mantle plaques present (Figs 38–40). Internally, valves linear-lanceolate, with subcapitate to rostrate poles; striae biseriate almost opposite each other, near sternum becoming uniseriate (Figs 49–51). Rimoportulae prominent, possessing the characteristic bilabiate shape, lying close to the sternum (Figs 49, 51).  
 Type: — CHINA. Hunan: Zhangjiajie National Forestry Park, the course of Jinbian stream, at Shuirao Simen, 29°20’36” N, 110°28’13” E, 467 m a.s.l., Bing Liu,  29 th December 2015 , (holotype BM! 101839, illustrated in Fig. 30; isotype JIU! G201605, illustrated in Fig. 35, both holotype and isotype indicated on the slide).   
 Etymology: —The epithet ulnabiseriata is a combination of ulna and the term ‘biseriate’ to reflect its similarity to U. ulna and its biseriate striae.   
 Ecology:— The following environmental parameters were measured in the field. Electric conductivity was 102.7 ± 0.8 μS/cm, pH was 8.5 ± 0.7, and water temperature was 8.7 ± 0.2 °C. Since the diatom sample was scraped off the surfaces of stones and the water electric conductivity is near 100 μS/cm, Ulnaria ulnabiseriata can be considered an epilithic diatom characteristic of moderate electrolyte content freshwaters.
description: Published as part of Liu, Bing, Williams, David M. & Tan, Lin, 2017, Three new species of Ulnaria (Bacillariophyta) from the Wuling Mountains Area, China, pp. 241-258 in Phytotaxa 306 (4) on pages 248-251, DOI: 10.11646/phytotaxa.306.4.1, http://zenodo.org/record/13695985