Angusticopula rowlingiana Van de Vijver, Wilfert, D.M.John & Houk, 2019

Vijver, Bart Van De, Wilfert, Sandra, Houk, Vaclav & John, David M., 2019, Angusticopula rowlingiana, a new melosiroid diatom (Bacillariophyta) from Ascension Island (South Atlantic Ocean), Phytotaxa 388 (2), pp. 155-160 : 156

Angusticopula rowlingiana Van de Vijver, Wilfert, D.M.John & Houk sp. nov. ( Figs 1–18 )

LM ( Figs 1–12 ): Frustules cylindrical to short barrel-shaped. Cells always solitary, chains, even short ones, never observed. Numerous discoid plastids present. Valve diameter (n=50): 11.0–15.0 μm, valve height 5.5–6.5 μm. Valves dome-shaped with a relatively low mantle and rounded, flat valve face. Internal valves occasionally present. SEM ( Figs 13–18 ): Valves clearly flat with a low mantle ( Fig. 13 ). Spines absent ( Fig. 15 ). Valves perforated by an irregular pattern of very small, rounded areolae, never arranged into a regular striation pattern ( Fig. 16 ). Valve face/mantle junction covered with small, rounded granules surrounding the entire valve margin ( Figs 15, 16 ). Cingulum composed of a large number of narrow, open, unperforated ligulate copulae ( Figs 13–14 ). Copulae fimbriate on the lower part ( Fig. 14 , black arrows). Internal valves dome-shaped ( Figs 13, 14 ), perforated by a regular pattern of small pores. Small granules covering the internal valves with a higher concentration of conical granules in the lower part of the internal valves ( Fig. 14 , white arrows). Internally, irregular ring of rather large rimoportulae present near the mantle edge ( Fig. 17 , arrows). Internal valve surface perforated by numerous small areolae ( Fig. 18 ).

Type:— Ascension Island, Atlantic Ocean, Sample Bamboo (14°20’51.53”W / 7°57’6.48”S) (leg. S. Pressel & J. Duckett, April/ May 2014) (holotype BR!, slide no. 4539, isotype PLP! slide no. 354, University of Antwerp, Belgium).

Etymology:—The species is named after the famous British writer Mrs. J.K. Rowling to honor her for all her efforts to make children read books again, a first step in a possible future career as a scientist.

Ecology & Distribution:— Angusticopula rowlingiana was extremely dominant in a very wet moss sample taken from a moss ball associated with bamboo roots on Green Mountain. The sample was further characterized by the presence of Eunotia meridioatlantica Van de Vijver et al. (2018: 231) and several Humidophila species.

Figures

FIGURES 1–12. Angusticopula rowlingiana Van de Vijver, Wilfert, D.M.John & Houk sp. nov. Light microscope pictures taken from the holotype population (sample from Bamboo) from Green Mountain, Ascension Island. Figs 1–3 LM photographs of several frustules and valves in girdle and valve face view showing numerous discoid plastids. Figs 4–7 LM photographs of frustules in girdle view. Figs 6 & 7 show the presence of internal valves. Figs 8–12 LM photographs in valve face view. Scale bar represents 10 μm.

FIGURES 13–18. Angusticopula rowlingiana Van de Vijver, Wilfert, D.M.John & Houk sp. nov. Scanning electron microscope pictures taken from the holotype population (sample from Bamboo) from Green Mountain, Ascension Island. Fig. 13 External (mantle) view of one valve together with an internal valve; several narrow copulae are visible. Fig. 14. External (mantle) view of an internal valve show its typical domed structure and the granules. Note the dense concentration of granules on the lower part of the internal valve (see arrows) and the numerous narrow copulae with fimbriate lower part (black arrows). Fig. 15. External valve face view showing the marginal granules and the very small pores on the valve face. Fig. 16. External detail of the margin of the valve face with a dense number of small, rounded granules and small pores. Fig. 17. Internal view of an entire valve showing the position of the rimoportulae (arrows). Fig. 18. Internal detail of the valve face surface with the rimoportulae (arrows) and small pores. Scale bars represent 10 μm in Figs 13–15 & 17 and 1 μm in Figs 16 & 18.