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Eunotia panda Veselá et Johansen spec. nov. (Figs 56–103) Type:— USA. Maine: Acadia National Park, Big Heath (wetland next to Rd 102A), 44.233962° N, 68.320719° W, 5 June 2008, Veselá 008 (ANSP!). The holotype designated here, holotype slide ANSP GC 59085, Fig. 71 depicts the holotype (14.35 mm south by 5.05 mm east from the benchmark cross on the slide); isotype slide ACAD 54522b, stored at J. R. Johansen’s collection at John Carroll University, Ohio, USA (isotype specimen in Fig. 74, 7.0 mm south by 9.0 mm east from the benchmark cross on the slide). Valves are arcuate, isopolar, having a curvature of 0.74–1.00 radians, with a slight increase in curvature from the largest to the smallest valves (Figs 56–86), with length to breadth ratio 12–27:1, 33–97 µm long, 3–4 µm wide (mostly 3.5 µm). Ventral and dorsal valve margins are parallel through most of the valve, only tapering very near the apices, slightly reflexed dorsally at the weakly protracted ends (Figs 56–87). Valve apices bear many minute, sharp siliceous protrusions, which are situated irregularly between the striae or areolae (Figs 88, 90, 93, 95). Valve margins are typically sharply beveled with a single row (rarely double rows) of areolae in the beveled portion (Fig. 89). In LM the raphe is distinct, but short. It begins on the valve mantle (Fig. 92), and curves subapically on the valve face back towards the main part of the valve (Figs 87–93, 95) as visible from SEM. The raphe is centered in the apical region, with external fissures visible on the external portion of the valve (e.g., Figs 88, 95), but not penetrating the internal part of valve past the helictoglossa (Figs 96–103). Helictoglossa is visible in the LM (Figs 56–86). A single rimoportula, placed at the apex, is present per valve (Figs 96–103). Striae are lowered in between hyaline ridges, parallel in the center of the valve, radiating towards the apices (Figs 56–93), 14.5–17(20) in 10 µm in the center valve, up to 21 in 10 µm near the apices. Areolae are open, rounded with irregular edges or irregular in shape (Figs 88–90, 92–95, 98, 99, 101, 102), 33–40 in 10 µm. Etymology:—From the Latin adjective pandus (i.e. curved, arched), referring to the curvature of the valves. Ecology and distribution:—Our populations of E. panda were observed in ponds, streams and wetlands in all three major parts of Acadia National Park (Table 1). The taxon is probably more widely distributed in suitable habitats around the Holarctic region (see below). Observations:— Eunotia panda is similar in shape to Eunotia bilunaris (Ehrenberg 1832: 87) Schaarschmidt (1881: 159) but differs in the apices which are slightly recurved dorsally. It is also similar in shape to Eunotia cantonatii Lange-Bertalot et Tagliaventi in Lange-Bertalot et al. (2011: 72), but differs by having valve ends much less tapered, by the absence of the single apical hollow protrusion visible in SEM views of E. cantonatii and by possessing small irregular sharp protrusions between striae at the tip of each valve apex (Figs 88, 93, 95). Eunotia panda differs from both species and other members of the E. bilunaris complex by the coarser areolation, 33–40 in 10 µm as opposed to 40–45 in 10 µm (Table 2). Eunotia panda is probably related to E. bilunaris, because it possesses a similar valve outline and fits most of the measurements (Table 2). However, our populations are very distinct and probably represent a semicryptic species within E. bilunaris sensu lato. The valves of E. panda are mostly 3.5 µm wide and slightly arched. Valve ends are slightly narrowed toward rounded and weakly dorsally reflexed ends. It is worth noticing that the valve outline of this taxon is very constant throughout the size-diminishing process of its life cycle. The distribution of Eunotia panda is probably not restricted to North America. It has also been observed in Europe, although always identified as E. bilunaris (Krammer & Lange-Bertalot 1991, Lange-Bertalot et al. 2011). Several such specimens, very similar to E. panda, were reported, for example, from various localities around Europe by Lange-Bertalot et al. (2011): a dystrophic habitat in Black Forest, SW Germany (pl. 27, fig. 7), a peat bog in the European part of Russia (pl. 27, fig. 17), the spring of Odra River, Czech Republic (pl. 30, fig. 13), and a peat bog in Tatra Mountains, Poland (pl. 31, fig. 14). Unfortunately, no published reports of SEM or LM examinations of the type material of E. bilunaris have yet appeared, so we do not know the exact nature of this taxon. Lange-Bertalot et al. (2011) provide ultrastructural characterization of what they consider to be E. bilunaris (pl. 33, figs 1–7), and their specimens significantly differ from the ultrastructure details of E. panda. Eunotia panda possesses small, unoccluded, rounded to irregularly shaped areolae as opposed to the well occluded larger areolae and smooth valve surface of the apices of E. bilunaris. Besides the taxa mentioned in the diagnosis, E. panda also shares some features with E. juettnerae Lange-Bertalot in Lange-Bertalot et al. (2011: 127) or E. mucophila (Lange-Bertalot, Nörpel-Schempp et Alles) Lange-Bertalot in Metzeltin et al. (2005: 53). Despite the fact that E. juettnerae has slightly arched valves and similar valve breadth in the center of the valve, it differs in the valve outline as the valves are narrowed significantly from the valve center toward the tapered ends. In contrast, E. mucophila has similarly shaped valves to E. panda, i.e., slightly arched, with parallel margins throughout the valve, and even with apices slightly recurved dorsally. However, E. mucophila is usually less silicified (appearing more delicate), has narrower valves (1.9–2.7 µm) with denser striation (18–25 in 10 µm) and areolation (43–48 in 10 µm, Lange-Bertalot et al. 2011)., Published as part of Veselá, Jana & Johansen, Jeffrey R., 2014, Three new Eunotia (Bacillariophyta) species from Acadia National Park, Maine, USA, pp. 181-200 in Phytotaxa 175 (4) on pages 189-190, DOI: 10.11646/phytotaxa.175.4.1, http://zenodo.org/record/5153639, {"references":["Ehrenberg, C. G. (1832) Uber die Entwicklung und Lebensdauer der Infusionsthiere; nebst ferneren Beitragen zu einer Vergleichung ihrer organischen Systeme. Abhandlungen der Koniglichen Akademie der Wissenschaften zu Berlin 1831: 1 - 154.","Schaarschmidt, G. (1881) Algae in A Kanitz, Plantas Romaniae hucusque cognitas. Magyar Novenytani Lapok 5: 151 - 165. http: // dx. doi. org / 10.5962 / bhl. title. 9950","Lange-Bertalot, H., Malgorzata, B. & Witkowski, A. (2011) Diatoms of the European inland water and comparable habitats: Eunotia and some related genera. Diatoms of Europe 6: 1 - 747. http: // dx. doi. org / 10.1080 / 037454809495289","Krammer, K. & Lange-Bertalot, H. (1991) Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. In: Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (eds.) Susswasserflora von Mitteleuropa 2 (3). Gustav Fisher Verlag, Stuttgart, Germany, pp. 1 - 576.","Metzeltin, D., Lange-Bertalot, H. & Garcia-Rodriguez, F. (2005) Diatoms of Uruguay. Compared with other taxa from South America and elsewhere. Iconographia Diatomologica 15: 1 - 736."]}

Eunotia spatulata Veselá et Johansen spec. nov. (Figs 104–133) Type:— USA. Maine: Acadia National Park, Halfmoon Pond, 44.391172° N, 68.251052° W, 10 June 2008, Veselá 081b (ANSP!). Water characteristics: pH 4.6, water temperature 24.6°C, conductivity 22.9 µS. The holotype designated here, holotype slide ANSP GC 59086, Fig. 114 depicts the holotype (118.85 mm south by 122.2 mm east from the benchmark cross on the slide); isotype slide ACAD 54652b, stored at J. R. Johansen’s collection at John Carroll University, Ohio, USA (isotype specimen in Fig. 116, 8.9 mm south by 8.4 mm west from the benchmark cross on the slide). Valves are straight, narrowing very gradually and slightly from the center to the subapical portion, from which the valves widen abruptly into the widely spatulate apices (Figs 104–117), 159–272 µm long, 3.3–4.0 µm wide in center, 1.9–2.8 µm wide in narrowest part, 5.3–6.4 µm wide at apices. The apices are inflated more on the dorsal side than the ventral side and appear flattened at the ends (Figs 104–117). The valve edges are sharply beveled with one to two rows or areolae in the beveled section (Figs 120, 121, 124). Irregularly arranged siliceous ridges are present at the apical margins of the valves (Figs 119, 121–123). Raphe begins on the valve mantle, and curves subapically on the valve face back towards the main part of the valve. It is centered with respect to the main axis of the valve but closer to the ventral margin because of the unevenly widened apices (Figs 119, 121–123). External raphe fissure is visible on the external portion of the valve (e.g., Fig. 122), but does not penetrate the internal part of valve past the helictoglossa, where it is internally occluded by a hyaline linear area interrupting the striae past the helictoglossa (Figs 126, 127, 130, 131). A single rimoportula is present on each valve, and is located within the apical edge adjacent to the helictoglossa (Figs 122, 123, 127, 129), usually visible in the LM (Figs 104b, 105b, 107b). Striae are fine and parallel throughout the valve, including the apices, where they are spaced more densely (Figs 126–133), 18–21 in 10 µm, up to 23.5 in 10 µm at the ends. Areolae are circular and externally occluded (Fig. 122), 33–40 in 10 µm. Etymology:—From the Latin spatulata, referring to the spatulate outline of the valve apices. Ecology and distribution:— Eunotia spatulata was observed in only six localities (mostly ponds) from Mount Desert Island, Acadia National Park, Maine, USA (Table 1). Observations:— Eunotia spatulata is similar to Eunotia eurycephala (Grunow in VanHeurck 1881: fig. 35:8) Nörpel-Schempp et Lange-Bertalot in Lange-Bertalot & Metzeltin (1996: 48), from which it differs by having longer valves and more broadly widened apices (Table 2). It is also similar to Eunotia eurycephaloides Nörpel-Schempp et Lange-Bertalot in Lange-Bertalot & Metzeltin (1996: 48), from which it differs by having straight, non-arcuate valves and much more broadly widened ends (Table 2). E. spatulata is part of a species cluster that includes E. eurycephala and E. eurycephaloides. Grunow showed only one drawing of what he called “ E. flexuosa var.? eurycephala ”, and it was a long, thin straight valve with distinctly widened ends (in Van Heurck 1881). Cleve-Euler gave two drawings of her interpretation of E. flexuosa γ eurycephala Grunow: one is straight while the other is very arcuate (Cleve-Euler 1953, figs 419 f, g, respectively). Apices of these valves were much larger than what other authors have shown for their taxa. Eunotia eurycephala was erected as a status novus in the same work where E. eurycephaloides was described (Lange-Bertalot & Metzeltin 1996). Eunotia eurycephaloides was illustrated as being slightly to distinctly arcuate and 60–150 µm long, with apices not as enlarged as shown in the previous literature for E. eurycephala. Later, Lange-Bertalot et al. (2011) synonymized E. eurycephaloides with E. eurycephala stating that with more populations seen the two taxa could not be separated. We are not convinced that this is so. From the images and drawings shown for these taxa, E. eurycephaloides is arcuate and has the least enlarged apices (up to 4 µm wide), E. eurycephala is almost straight and has broader ends (up to 4.5 µm wide). Regardless of the fate of these two taxa, E. spatulata is distinct from both, with completely non-overlapping valve length (159–272 µm long compared to less than 150 µm long, Table 2), much wider non-overlapping width of the apices (5.3–6.4 µm wide, Table 2), and ultrastructural details (e.g., no irregular siliceous ridges on external apical margins of E. eurycephala). Additionally, in none of the earlier drawings or images is the valve outline shown to distinctly narrow from the center towards the apices with the narrowest width in a subapical region of the valve. More study of E. eurycephala, E. eurycephaloides, and the related taxon E. eurycephala var. pachycephala Grunow in Van Heurck (1881: fig. 35:7) is needed to test the differences in these taxa that we can detect now with the limited study they have received., Published as part of Veselá, Jana & Johansen, Jeffrey R., 2014, Three new Eunotia (Bacillariophyta) species from Acadia National Park, Maine, USA, pp. 181-200 in Phytotaxa 175 (4) on page 194, DOI: 10.11646/phytotaxa.175.4.1, http://zenodo.org/record/5153639, {"references":["Lange-Bertalot, H. & Metzeltin, D. (1996) Indicators of Oligotrophy. 800 taxa representative of three ecologically distinct lake types: Carbonate buffered - Oligodystrophic - Weakly buffered soft water. Iconographia Diatomologica 2: 1 - 390.","Lange-Bertalot, H., Malgorzata, B. & Witkowski, A. (2011) Diatoms of the European inland water and comparable habitats: Eunotia and some related genera. Diatoms of Europe 6: 1 - 747. http: // dx. doi. org / 10.1080 / 037454809495289"]}