Frankophila dalevittii Van de Vijver & Goeyers 2020, sp. nov.
Creators: name: Vijver, Bart Van De
name: Ballings, Petra
name: Goeyers, Charlotte
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Chromista
Ochrophyta
Bacillariophyceae
Fragilariales
Fragilariaceae
Frankophila
Frankophila dalevittii

description: Frankophila dalevittii Van de Vijver & Goeyers sp. nov. (Figs 1–39)
LM (Figs 1–30): Frustules rectangular in girdle view, forming long chains of several tens of frustules, connected by relatively large, interdigitating linking spines (Figs 1–4). Valves linear-elliptical to elliptical and even elliptic-lanceolate. Smallest specimens almost rounded. Apices never protracted, always broadly rounded. Elliptic-lanceolate specimens with less broadly rounded apices. Valve dimensions (n=50): length 4–15 µm, width 3–5 µm. One initial valve observed: length 33 µm, width 6 µm. Axial area moderately wide, almost 1/3 of total valve width, lanceolate to linear-lanceolate. Central area lacking. Striae parallel in the valve centre becoming distinctly radiate towards the apices, 11–12 in 12 µm. Areolae not discernible in LM. SEM (Figs 31–39): Girdle composed of at least two open, non-perforated copulae (Figs 31, 33). Copulae often covered by irregular pattern of small ridges and granules (Figs 31, 32). Mantle very broad with clearly undulating edge (Fig. 32). Lower part of the mantle hyaline, covered with fine silica granules (Fig. 32). Frustules connected to each other via well-developed, interdigitating linking spines (Figs 31, 32, 34). Spines solid with dichotomously branching ends (Fig. 34), located on the virgae between the striae (Figs 35, 36). External raphe vestiges absent (Figs. 35, 36) although shallow depressions occasionally observed where slits were expected (Figs 35, 36, arrows). Striae composed of two rows of rather large, rounded areolae, terminating near the axial area by one areola. Striae continuing shortly but uninterruptedly onto the valve mantle. Rimoportulae and apical porefields absent (Figs 36, 38). Internally, short raphe slits visible near the valve apices (Figs 37, 38, 39, arrows), <0.5 µm long. Areolae located in deep grooves (Figs 37, 38).
Type:—Perseverance Harbour east of Moubray Hill, Campbell Island, sub-Antarctic Region, sample BAS 303 (leg. D. Vitt, coll. date: 12/01/1970) (holotype BR!, slide no. 4574, isotype PLP! slide no. 367, University of Antwerp, Belgium).
Etymology:—the species is named after Dr. Dale Vitt (Southern Illinois University Carbondale, USA), who collected in the austral summer of 1969–1970 the moss samples used in this study. His collection forms the base of an important contribution to the biogeography and biodiversity of the non-marine diatoms of the sub-Antarctic islands in the southern Pacific Ocean.
Ecology:— Frankophila dalevittii was observed in three moss samples on Campbell Island. The largest population (up to 10% of all diatom valves in the sample) was found in a Racopilum strumiferum vegetation on wet rock under a large overhang in a cave next to sea. The accompanying diatom flora is composed of several melosiroid taxa (that are currently being described as new taxa, Goeyers & Van de Vijver, unpubl. res.), Rhopalodia sp., Diatomella balfouriana Greville (1855: 259) and Diatomella colonialis Van de Vijver & Le Cohu (2017: 282).
description: Published as part of Vijver, Bart Van De, Ballings, Petra & Goeyers, Charlotte, 2020, Frankophila dalevittii, a new freshwater diatom (Bacillariophyta) from Campbell Island, pp. 57-64 in Phytotaxa 429 (1) on pages 58-59, DOI: 10.11646/phytotaxa.429.1.4, http://zenodo.org/record/13876795