Diploneis latissima, Jovanovska & Wilson & Hamilton & Stone, 2023

Jovanovska, Elena, Wilson, Mallory C., Hamilton, Paul B. & Stone, Jeffery, 2023, Morphological and molecular characterization of twenty-five new Diploneis species (Bacillariophyta) from Lake Tanganyika and its surrounding areas, Phytotaxa 593 (1), pp. 1-102 : 86

publication ID	https://doi.org/ 10.11646/phytotaxa.593.1.1
DOI	https://doi.org/10.5281/zenodo.7875225
persistent identifier	https://treatment.plazi.org/id/038487E2-FF8B-2617-BCF1-FF09BA2874C8
treatment provided by	Plazi
scientific name	Diploneis latissima
status	sp. nov.

Treatment

Diploneis latissima sp. nov. (LM Figs 567–576 View FIGURES 567–576 , SEM Figs 577–581 View FIGURES 577–581 )

Valves are weakly asymmetric, elliptic-lanceolate with convex margins and round ends ( Figs 567–577 View FIGURES 567–576 View FIGURES 577–581 ). Valve length is 31.5–48.5 μm and width is 23–29.5 μm. The axial area is narrow, linear to lanceolate ( Fig. 568 View FIGURES 567–576 ), patterned with irregular round ornamentations opened into small depressions that do not penetrate the silica cell wall (white arrow in Fig. 577 View FIGURES 577–581 ). The axial area slightly widens into a longitudinally elongate and weakly asymmetric central area, 3.8–5.5 μm wide. Externally, the canal is linear to lanceolate, slightly expanded in the middle of the valve with two to three rows of cribrate areolae narrowing into one larger at the valve apices ( Fig. 577 View FIGURES 577–581 ). Internally, a thick non-porous slightly raised silica plate encloses the longitudinal canal ( Fig. 580 View FIGURES 577–581 ). Externally, the raphe is filiform with slightly arched branches ( Fig. 577 View FIGURES 577–581 ). The distal raphe ends are unilaterally bent ( Fig. 577 View FIGURES 577–581 ). The raphe system is from the outside followed by irregularly positioned roundish structures located between the raphe and the row of areolae (white arrow in Fig. 577 View FIGURES 577–581 ). Internally, the raphe is curved and placed in the depression formed by the longitudinal canal ( Fig. 580 View FIGURES 577–581 ). The striae are parallel at mid-valve becoming radiate towards the valve apices, 8–9 in 10 μm. Striae are biseriate throughout ( Figs 578, 579 View FIGURES 577–581 ). The striae are composed of round depressed areolae covered externally with fine pored cribra (ca. 40 poroids), 15–18 in 10 μm. The interstriae are distinct ( Fig. 579 View FIGURES 577–581 ). Internally, the alveoli open via a single elongate opening covered with a thin silica layer ( Fig. 581 View FIGURES 577–581 ). The valvocopula has serrated advalvar edges ( Fig. 580 View FIGURES 577–581 ).

Type:— REPUBLIC OF ZAMBIA, Mulungushi River , at 1117 m elevation; mud, 0.1 m water depth, 14°17’45.6” S 28°32’54.8” E, E. Jovanovska & Z. Levkov, 27 th September 2021 (holotype designated here, circled specimen BM-108975! = Fig. 575 View FIGURES 567–576 , GoogleMaps isotypes ANSP-GC17204 !, CANA-129322!). Type material CANA-129322. Registration: http:// phycobank.org/103711 GoogleMaps

Pictures of the isolated specimen:— LM micrograph on 1000× magnification ( Fig. S3n View FIGURES 2–11 ).

Sequence data:— Plastid gene rbc L sequence (GenBank accession: OQ 660299) and nuclear encoded 18S ( SSU rDNA) sequence (GenBank accession: OQ 629558).

Etymology:— The specific epithet ‘ latissima ’ refers to the broad width of the valve.

Ecology and distribution:— This species was observed only in the Mulungushi River, which has a moderately alkaline pH (7.9), a low conductivity of 101 μS̔ cm-1, and low water transparency. It coexists with Diploneis dissipata sp. nov. and D. distinctebipunctata sp. nov.

Main differential characters:— Valve width and shape, striae pattern, areolae offset, poroids ca. 40 per areola.