Ferocia ninae Van de Vijver & Houk, 2017

Vijver, Bart Van De, Chattová, Barbora, Lebouvier, Marc & Houk, Václav, 2017, Ferocia gen. nov., a new centric diatom genus (Bacillariophyceae) from the sub-Antarctic region, Phytotaxa 332 (1), pp. 22-30 : 26-28

Ferocia ninae Van de Vijver & Houk sp. nov. (Figs 28–45)

LM (Figs 28–40): Frustules cylindrical to almost spherical with hemispherical valves bearing a large number of acute linking spines connecting the frustules forming short chains of up to 3–5 cells. Valve diameter (n=50): 4.5–19.0 μm, valve height 4.0–6.0 μm. Spines usually arranged around the valve face. Valves dome-shaped with a relatively low mantle and rounded valve face. Internal valves occasionally present. SEM (Figs 41–45): Valves clearly hemispherical with a low mantle (Fig. 43). Linking spines relatively large, irregularly shaped, with sharp, acute endings (Figs 42, 43). Valve face entirely covered by a large number of smaller spines and irregularly shaped granules positioned between the large linking spines (Fig. 43). Müller step often very large (Fig. 43). Cingulum composed of a large number of narrow,

Figures 41–45. Ferocia ninae Van de Vijver & Houk sp. nov. LM. Ile de la Possession type population (sample BA061). Fig. 41. Two frustules connected by linking spines with the cingulum composed of numerous narrow, ligulate open copulae. Fig. 42. View of an entire valve showing spines and valve face areolae. Fig. 43. External view of a hemispherical valve in girdle view showing the spines and the rather low mantle with areolae. Fig. 44. Internal view of an entire valve showing the ring of rimoportulae (arrows). Fig. 45. Internal detail of the rimoportulae. Scale bar represents 10 μm except for fig. 45 where scale bar = 1 μm.

open, unperforated ligulate copulae (Fig. 41). Pars interior of the copulae fimbriate (Fig. 41). Areolae on the mantle edge small, rounded, arranged in irregular rows, parallel to the pervalvar axis (Fig. 43). On the valve face, areolae often slit-like, arranged in star-shaped patterns around the spines (Fig. 42). Internally, ring of slit-like, equidistantly placed rimoportulae present near the mantle edge (Fig. 44, arrows). Areolae internally individually covered by vela (Fig. 45).

Type: —Pointe Basse, Ile de la Possession, Crozet Archipelago, Sub-Antarctica, sample BA61, (leg. B. Van de Vijver), coll. date 21/11/1999 (holotype BR!, slide no. 4498, isotype PLP! slide no. 332, University of Antwerp, Belgium).

Etymology: —The species is named after Mrs. Nina Marchand (IPEV, France) to thank her for the help during the sampling campaigns on Ile Amsterdam (2007 & 2016) and Ile de la Possession (2012).

Ecology & Distribution:—The new species was found in dry soil samples collected from several shallow lava caves and caverns on the border of the small river that is flowing in the Pointe Basse Region. The samples were dominated by Planothidium aueri ( Krasske 1949: 77) Lange-Bertalot (1999: 281) , several Humidophila taxa such as H. subantarctica ( Le Cohu & Van de Vijver 2002: 128) R.L. Lowe et al. (2014: 359) and H. arcuata (Heiden in Heiden & Kolbe 1928: 628) R.L. Lowe et al. (2014: 357) and Chamaepinnularia aerophila Van de Vijver & Beyens in Van de Vijver et al. (2002a: 26).