FIGURES 20–25 in A new Fragilaria Lyngbye species (Fragilariaceae, Bacillariophyta) from a historic Grunow sample from the Attersee, Austria

FIGURES 20–25. Scanning electron micrographs of Fragilaria crocodylus Van de Vijver & C.E.Wetzel sp. nov. SEM images taken from the holotype population (BR-4736, Grunow sample 2646, Attersee, Austria). 20. SEM external view of an entire valve. Note the continuous series of marginal spines running from apex to apex and the lack of rimoportula at one apex. 21. SEM girdle view of two valves connected to each other via the short, conical spines. 22. SEM side view of the valve apex showing mantle plaques, the apical pore field, five protruding conical spines at the apex and the depressed rimoportula. 23. SEM external view of a valve apex showing the rimoportula, the conical spines on their pit-like depressions and the uniseriate striae with the combination of rounded and slit-like areolae. 24. SEM external detail of the central area. Note the slit-like areolae terminating the striae at the sternum. 25. SEM internal detail of a valve apex with the large rimoportula. Scale bars = 10 μm (Figs 20–21), 1 μm (Figs 22–25). ; Published as part of Vijver, Bart Van De & Wetzel, Carlos E., 2022, A new Fragilaria Lyngbye species (Fragilariaceae, Bacillariophyta) from a historic Grunow sample from the Attersee, Austria, pp. 210-214 in Phytotaxa 561 (2) on page 212, DOI:10.11646/phytotaxa.561.2.9, http://zenodo.org/record/7059546