Ctenophora hunanensis Bing Liu & Rioual, 2024

Xiang, Dong-Qin, Yang, Rui, Rioual, Patrick, Zheng, Yan & Liu, Bing, 2024, Ctenophora hunanensis sp. nov. (Bacillariophyta) from the Yongle River in Hunan Province, China, PhytoKeys 250, pp. 181-191 : 181-191

publication ID

https://doi.org/ 10.3897/phytokeys.250.140576

DOI

https://doi.org/10.5281/zenodo.14562783

persistent identifier

https://treatment.plazi.org/id/2F3135BC-BBD4-5344-A321-1A9BB1829F96

treatment provided by

PhytoKeys by Pensoft

scientific name

Ctenophora hunanensis Bing Liu & Rioual
status

sp. nov.

Ctenophora hunanensis Bing Liu & Rioual sp. nov.

Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5

Holotype.

Specimen circled on slide DIA 2024010 (= Fig. 2 B View Figure 2 ), deposited in the Herbarium of Jishou University ( JIU), China. Registration: http://phycobank.org/105130. View Materials GoogleMaps

Type locality.

China. Hunan Province: Anren County, Yongle River   GoogleMaps , sampling site with the coordinates 26°50'12"N, 113°35'59"E, and an elevation of 123 m asl. Diatom samples collected by Bing Liu, March 24, 2024.

Description.

LM (Fig. 2 View Figure 2 ). Valves lanceolate with rostrate apices. Valve dimensions (n = 30): length 48–78 μm, width 6.5–8.5 μm at center. Sternum clearly visible, gradually widening when approaching central area. Central area distinct, rectangular to square, sometimes with ghost striae. Striae parallel, uniseriate, perpendicular to central sternum, opposite one another across sternum. Stria density 13–16 in 10 μm. Areolae punctate, 20 in 10 μm. Many abnormal valves are found, all of which exhibit the asymmetry relative to the apical axis due to the V-shaped incising of valve margin only occurring at one side (Fig. 2 C, E, H View Figure 2 ).

SEM (Figs 3 View Figure 3 – 5 View Figure 5 ). Sternum meeting and integrated with virgae, vimines reduced in size relative to virgae. Virgae and vimines join to form square to rectangular areolae that are closed externally by complex cribra appearing as sieve-like closing plates composed of pegged struts (Fig. 3 D – F View Figure 3 ). Inner openings of areolae appear rounded (Fig. 4 C, D View Figure 4 ). Central area distinctive, externally a broad plain area (Fig. 3 D View Figure 3 ), internally thickened around its periphery, ghost striae within (Fig. 4 D View Figure 4 ). One rimoportula present at each apex, externally expressed as a simple hole (Fig. 3 E, F View Figure 3 ), internally bilabiate, situated close to sternum (Fig. 4 E, F View Figure 4 ). Ocellulimbus produced at each apex, typically sunken below surface of valve margin (Fig. 3 E, F View Figure 3 ). Valvocopula open, lacking ornamentation, distinctly deeper than copulae (Fig. 5 View Figure 5 ). On its advalvar edge, valvocopula bears a row of serrated projections, each corresponding internally to a virga (Fig. 5 View Figure 5 , three arrows). Copulae with row of poroids situated at pars media (Fig. 5 View Figure 5 , two wavy arrows).

Etymology.

Named after Hunan Province where the species was found.

Distribution and ecology.

Known only from the type locality. The samples that included this species were scraped off the surface of stones collected in the Yongle River. Hence this is a benthic, epilithic species. The relative abundance of this new species is ca. 3 %. The associated taxa include Gomphonema parvulum (Kützing) Kützing , Luticola spp. , Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot , Tryblionella spp. , Nitzschia spp. , among others. The following environmental parameters were measured in the field with three replications: Conductivity = 85.9 ± 0.1 μS cm - 1; pH = 8.9 ± 0.1; Water temperature = 22.3 ± 0.3 ° C.