Kurtkrammeria salesopolensis Marquardt, A.

Marquardt, Gisele C., Da Rocha, Angélica C. R., Wetzel, Carlos E., Ector, Luc & Bicudo, Carlos E. De M., 2016, Encyonema aquasedis sp. nov. and Kurtkrammeria salesopolensis sp. nov.: two new freshwater diatom species (Cymbellales, Bacillariophyceae) from an oligotrophic reservoir in southeastern Brazil, Phytotaxa 247 (1), pp. 62-74 : 66

Kurtkrammeria salesopolensis Marquardt, A. Rocha & C.E.Wetzel, sp. nov. ( Figs 12–23, 15–33 )

Valves linear-lanceolate, not or scarcely dorsiventral in the larger forms and slightly dorsiventral in the smaller ones. Length 41.6–78.7 μm. Breadth 5.3–7.4 μm. Dorsal side slightly convex. Ventral side slightly convex to straight. Valvar margins sometimes tumid in the middle region. Apices narrow, sub-rostrate, rounded, slightly curved to ventral side. Raphe filiform, slightly lateral with proximal fissures slightly expanded, curved to dorsal margin; distal raphe ends comma-shaped, sharply bent to the ventral margin. Axial area approximately 1/3 the valve breath, linear, forming a narrow longitudinal lanceolate hyaline area slightly widening to the central area. Central area variable, absent to linear lanceolate. Striae uniseriate, parallel to slightly radiate, 13–14 in 10 μm, composed of lineolate areolae visible only in the SEM, apically elongated, sometimes “Y” disposed, approximately 33 in 10 μm. Shortened striae continue around valve apices. Isolated punctum absent.

Type:— BRAZIL. São Paulo (SP), Salesópolis: Ribeirão do Campo reservoir, sediment core, 23º 38.514’ S, 45º 49.854’ W, A. C. R. Rocha & D. C. Bicudo, 13 August 2010 (holotype: SP!, slide 427990, here depicted in Figs 12–23 . Isotype: BR!, slide 4431).

Etymology:—The Latin name salesopolensis refers to the municipality of Salesópolis where samples were collected.

Additional morphological data:—External raphe fissure are slightly undulate ( Fig. 32 ), located approximately in the mid region of the valve. Proximal end of raphe almost straight, the enlarged proximal endings slightly curved to the dorsal side ( Figs 32–33 ). Distal raphe ends are comma-shaped, first dorsally bent, then strongly hooked to the ventral side ending onto the mantle ( Figs 32, 35–36 ). Axial area is linear-lanceolate ( Fig. 32 ) to form a lanceolate central area, formed by very slightly shortened striae on ventral side and on dorsal side. Striae uniseriate, composed of apically-elongated areolae, sometimes “Y” disposed ( Figs 32–34, 36–38 ) numbering 33 in 10 μm, radiate near the valve center, becoming parallel, then convergent near the apices. Transapically-elongated areolae, different shape and size, in shortened striae continuing around the apex ( Figs 32, 34, 37–38 ), numbering 13–14 in 10 μm. Internally, struts provide structural support to the foramen, whose opening bears one very short spine at each side ( Figs 35–36 ). Internal proximal raphe ends are widely separated and strongly hooked towards the dorsal margin ( Fig. 36 ), and the distal endings terminate in well-developed helictoglossae that are deflected towards the ventral margin ( Fig. 35 ). No isolated punctum is present.

Ecology: — Encyonema acquasedis sp. nov. and Kurtkrammeria salesopolensis sp.nov. occur in acidic environments (pH 5.2–5.6), with water temperature around 17.6–25.5 °C and electric conductivity 10.4–12.4 μS cm-1 ( Table 1). The new species were rare in samples collected from the plankton and surface sediments (relative abundance ≤ 2%). In the planktonic samples both taxa were associated with species of Kobayasiella [i. e. K. micropunctata (H. Germain 1981: 234) Lange-Bertalot (1999: 267) and K. venezuelensis Metzeltin & Lange-Bertalot (2007: 155) ], Eunotia [ Eunotia sp. , E. botuliformis F.Wild, Nörpel & Lange-Bertalot in Lange-Bertalot (1993: 29) and E. veneris ( Kützing 1844: 40) De Toni (1892: 794) ], Frustulia [ F. crassinervia (Brébisson in Smith 1853: 47) Lange-Bertalot & Krammer in Lange-Bertalot & Metzeltin (1996: 57)] and Brachysira [ B. brebissonii R.Ross in Hartley (1986: 607) and B. serians ( Brébisson 1838: 18) Round & D.G.Mann (1981: 227) ]. On benthic samples they were, associated with Brachysira brebissonii , B. serians , Eunotia botuliformis , E. bilunaris ( Ehrenberg 1832: 87) Schaarschmidt (1881: 159) , E. incisa W. Gregory (1854: 96) , Eunotia sp. , Frustulia crassinervia and Frustulia sp.

Figures

FIGURES 2–23. Light micrographs. 2–11. Encyononema acquasedis. LM views showing variation in size and valve outline. 12–23. Kurtkrammeria salesopolensis. LM views showing variation in size and valve outline. Scale bars = 10 μm. Populations from type material SP427990 (surface sediments).

FIGURES 24–31. Scanning electron micrographs. Encyononema acquasedis. Population from type material (SP427990). 24–26. SEM external view of entire valve showing raphe and striae structure. 27. SEM internal view of entire valve showing raphe and striae structure. 28, 29. SEM internal detail of isolated punctum fissure and central area forming a very narrow intermissio. Note the areolae with struts providing structural support to the foramen. 30, 31. SEM internal detail of valve apex with helictoglossa.

FIGURES 32–38. Scanning electron micrographs. Kurtkrammeria salesopolensis. Population from type material (SP427990). 32. SEM external view of entire valve showing raphe and striae structure. 33. SEM external view showing areolae and central area. 34, 37–38. SEM external view of distal raphe ends. 35. SEM internal detail of valve apex with helictoglossa. 36. SEM internal detail of areolae and central area with intermissio.