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Introduction

The taxonomy of large groups of unicellular organisms has been a major focus in eukaryotic microbial research (Cavalier-Smith, Chao, & Oates, 2004, Nikolaev, Mitchell, Petrov, Fahrni, & Pawlowski, 2005). Testate amoebae represent one of these groups, a polyphyletic group of free-living protozoa, characterized by the ability to build shells (Adl et al., 2012), through which the pseudopodia protrude for locomotion or feeding (Porter & Knoll, 2000; Smith, Bobrov, & Lara, 2008).

Arcellidae is commonly recorded as one of the most representative families of testate amoebae in Neotropical ecosystems in terms of richness and abundance of species (Vucetich, 1973; Panarelli, Casanova, Nogueira, Mitsuka, & Henry, 2003; Fulone, Vieira, Velho, & Lima, 2005; Lansac-Tôha, Alves, Velho; Robertson, & Joko, 2008; Escobar, Brenner, Whitmore, Kenney, & Curtis, 2008; Oliveira & Hardoim, 2010; Arrieira, Alves, Schwind, & Lansac-Tôha, 2015). This family is characterized by specimens with shells made up of endogenous material, with discoid or hemispherical shape and centered pseudostoma (Souza, 2008). Within this family, Arcella is the genus with highest richness of taxa (Deflandre, 1928; Meisterfeld, 2002). Species are in their most of which is cosmopolitan and adapted to different environmental conditions in different aquatic biotopes (Deflandre, 1928; Lansac-Tôha, Velho, Zimmermann-Callegari, & Bonecker., 2000).

In general, Arcella has a high variability of morphological types, which combined with the paucity of descriptive studies, makes complex interspecific identification (Bobrov & Mazei, 2004). According to Lahr and Lopes (2009), this problem is more critical due to the lack of preserved specimens, and the poor standardization of the descriptive format of available works, hindering the new records.

The development of pictorial keys can be a tool to assist the description of species and facilitate the understanding of the characters described textually (Pimpão & Mansur, 2009). Furthermore, their use facilitates the identification of species, allowing reliable identifications by students and researchers unfamiliar with a particular group (Oliveira, Mianzan, Migotto, & Marques, 2007). Thus, this study aimed to provide the first list of testate amoebae of the Paranoá Lake and develop a pictorial key to the taxa of Arcella recorded in this environment.

Material and methods

Study area

The study was conducted in the Paranoá Lake (15°48’S; 47°50’W, Figure 1), an urban reservoir, occupying approximately 18% of the territory of the Federal District, Brazil (Mattos, Altafin, Freitas, Cavalcanti, & Alvez, 1992), with depht maximum 40m and about 111km perimeter. The Paranoá was created in 1959 from the damming of streams in the region, aiming to improve climate conditions in the region, promote recreation and for landscaping purposes (Ferrer & Del Negro, 2012; Ferrante, Nancan, & Netto, 2001).

Sampling design

Samples were collected at 13 sites flooded in the littoral region of Paranoá lake, all with the presence of marginal vegetation. The collection periods covered the dry season (August and September 2014) and rainy (April and May 2015). The collect took place in shallow areas, ranging 40-60 cm deep. Altogether, 100L of water was filtered with the aid of buckets and horizontal hauls in plankton net of 68μm and fixed in 70% ethanol.

Laboratory analysis

Sample sorting was performed on Sedgewick-Rafter chambers (2.5mL) integrally counted under an optical microscope. For each identified taxon, we took one or more specimens with the aid of pipette, and stored on slides, immersed in glycerin (90%), for better handling and morphological analysis.

Measurements were performed using the AxioVision software through images obtained by light microscopy (Olympus BX41) connected to the image capturing. They measured the height and length of the teak, and the diameter pseudostoma in one or more specimens.

Species of Arcella were identified with specific literature: Pénard (1890), Cunha, (1913), Deflandre (1928), Grospietsch (1954, 1958, 1972), Vucetich (1972, 1973), Ogden and Hedley (1980), Velho, Lansac-Tôha, & Serafim-Júnior (1996); Rhoden and Pitoni (1999), Meisterfeld (2002), Tsyganov and Mazei (2006), Alves, Lansac-Tôha, Velho, Joko, & Costa (2007), Lansac-Tôha et al. (2008), Souza (2008), and in cases of doubt, experts were consulted. Where possible, this study opted for identification of infraspecific taxa and took into account the morphospecies (Splitting method) (Mitchell & Meisterfeld, 2005).

Testate amoebae were photographed with a digital camera (Samsung Galaxy Camera) attached to the eyepiece of the optical microscope (Nikon Eclipse E 100), at lateral and ventral views. The ilustrations were held in image editing programs for higher representativity of the organisms.

The pictorial key was based on morphological characteristics (Figure 2) used to identify testate amoebae species: shape and ornamentation of the shell, presence or absence of undulations on the surface, types of ornamentation of the pseudostoma and presence or absence of borders and invaginations.

Samples of testate amoebae were deposited in the Laboratory of Limnology, Centro Universitário do Distrito Federal, as well as individuals used for taxonomic identification described herein.

Results

There were recorded 16 species and seven taxa infraspecific of Arcella distributed in the littoral region of the Paranoá Lake (Table 1).

ARCELLIDAE Ehrenberg, 1830

Arcella arenaria Greeff, 1866 (Figure 3.1a-1b).

Deflandre (1928: 247-249), Figures 293-297; Ogden & Hedley (1980: 24, pl. 1), Figures a-e.

Remarks: Lateral face, hemispherical shell, domed with slight undulations on the surface, with a flap on the shell base, and a small, invaginated buccal tube. Ventral face, circular shell, circular and central pseudostoma, pores present around pseudostoma.

Size: (n=4). Shell width 99.08-89.40μm; height 35.43-26.82μm; pseudostoma 21.87-19.45μm.

Arcella brasiliensis Cunha (1913) Figure 3.2a-2b.

Deflandre (1928: 242‑243), Figures. 263-265; Velho et al. (1996: 39, pl. I), Figure 4; Souza (2008: 71), Figure a-b; Lansac-Tôha et al. (2008: 184, pl.I), Figure1-1a.

Remarks: Lateral face, hemispherical shell, domed, small, buccal tube invaginated. Ventral face, circular shell with two inner circles which innermost is the pseudostoma aperture and the other is the beginning of the border with stretch marks.

Size: (n=8). Shell width 85.52-76.38μm; height 47.98-29.28μm; pseudostoma 23.80-16.88μm.

Arcella catinus Pénard, 1890 (Figure 3.3a-3b).

Deflandre (1928:243-247) (Figures 287-291).

Remarks: Lateral face, hemispherical shell, domed, slightly wavy, with border at the edge of the shell and buccal tube external to the shell, with collarette at the extremity of the pseudostoma. Ventral face, circular shell with circular and centered pseudostoma, pores around the pseudostoma.

Size: (n=5). Shell width 96.32-92.43μm; height 45.23-43.21μm; pseudostoma 21.86-20.83μm.

Arcella conica Playfair, 1917 (Figure 3.4a-4c).

Deflandre (1928:238-240) (Figures 244-255); Grospietsch (1972:7); Vucetich (1972: 273‑274, pl. I), Figure 2, 1973: 293, pl. I, Figure 8; Velho (1996, 40, pl. I), Figure 8; Souza (2008: 72), Figures a-b; Lansac-Tõhã et al. (2008: 184, pl.I), Figures 2-2a.

Remarks: Lateral face, pyramidal shell, concave and translucent, forming two polygons: one dorsal and another at the base of the shell. Dorsal face, shell with depressions, and angular facets of five sides. Ventral face, rounded shell, circular pseudostoma, centered and slightly invaginated.

Size: (n=8). Shell width 91.13- 103,4μm; height 77.07- 90.03μm; pseudostoma 25.89-31μm.

Arcella costata Ehrenberg, 1847 (Figure 3.5a-5c).

Deflandre (1928: 240-241), Figures 257-258; Vucetich (1973: 293, pl. I), Figure 9; Velho et al. (1996: 40, pl. I), Figure 7; Souza (2008: 73), Figures a-c.

Remarks: Lateral face, pyramidal shell with parallel sides, forming only one polygon. Ventral face, rounded shell, pseudostoma circular, centered and with little edge.

Size: (n=7). Shell width 104.34-74.72μm; height 81.70-49.59μm; pseudostoma 32.65-23.84μm.

Arcella crenulata, Deflandre, 1928, Figure 3.6a-6b.

Velho et al. (1996: 40, pl. I), Figure 6; Rhoden and Pitoni (1999: 94), Figure 2, Souza (2008: 74), Figures a-c.

Remarks: Lateral face, hemispherical shell. Ventral face, circular shell, edge with projections, similar to a short border. Lobated pseudostoma, invaginated, small and centered.

Size: (n=4). Shell width 118.76-111.97 μm; shell height 50.83-48.09 μm; pseudostoma 26.57-23.29μm.

Arcella dentata, Ehrenberg, 1838, Figure 3.7a-7b.

Deflandre (1928: 252), Figures 307, 310-314; Grospietsch (1958: 39), Figure 26.b; Vucetich (1973: 295), Figure 13; Velho et al. (1996: 40, pl. I), Figure 9; Meisterfeld (2002: 835); Figure 15; Souza (2008: 71), Figure a-b; Lansac-Tôha et al. (2008: 181, pl.1), Figure 4.

Remarks: Lateral face, discoid shell with projections in the form of lateral straight spines. Ventral face with thorn-shaped projections throughout the circumference of the shell. Pseudostoma small, circular and centered.

Size: (n=5). Shell width 132.23-130.00μm; pseudostoma 46.02-40.28μm.

Arcella dentata var. trapezica Deflandre, 1928, Figure 3.8a-8b.

Deflandre (1928: 254), Figures 315-317.

Remarks: Lateral face, discoid shell, domed, with projections in the form of lateral spines. Spines curved upward, nearly perpendicular to the base, forming a trapezoidal shell. Ventral face with thorn-shaped projections throughout the circumference of the shell, pseudostoma circular and centered. This is the first record of this subspecies in Brazil.

Size: (n=5). Shell width 149.88-125.36 μm; shell height 47.82-36.46μm; pseudostoma 40.46-34.64μm

Arcella discoides, Ehrenberg, 1843: A. discoidea in Ehrenberg (1843) Figure 3.9a-9b.

Deflandre (1928: 256-257), Figures 324-326; Grospietsch (1958: 41), Figure 28c; Vucetich (1973: 297), Figure 16; Velho et al. (1996: 43, pl. I), Figure 14; Souza (2008: 75), Figure a-c.

Remarks: Lateral face, discoid shell, invaginated buccal tube. Ventral face, circular shell. Pseudostoma circular, small and centered.

Size: (n=9). Shell width 154.96-115.59μm; shell height 31.05-21.50μm; pseudostoma 50.45-31.05μm

Arcella excavata Cunninham, 1919, Figure 3.10a-10b.

Deflandre (1928: 263-264), Figures 349-351.

Remarks: Lateral face, shell arcuate toward the pseudostoma. Ventral face, circular shell with circular pseudostoma, centered, with collarette at the aperture. Region of the pseudostoma more internal than the edges. This is the first record of this species in Brazil.

Size: (n=3). Shell width 122.56-120.30μm; shell height 42.33-41.44μm; pseudostoma 36.22-33.45μm

Arcella gibbosa, Pénard, 1890 (Figure 3.15a-15c)

Deflandre (1928: 227-229), Figures 190-206; Vucetich (1973: 291, pl. I), Figure 4; Velho et al. (1996: 39, pl. I), Figure 5; Souza (2008: 77), Figures a-b.

Remarks: Lateral face, hemispherical shell, rounded with depressions, presence of a small border on the extremity of the shell. Dorsal face, shell forming five vertices and depressions. Ventral face, circular shell with pseudostoma circular and centered.

Size: (n=1). Shell width 102.33μm; shell height 60.88μm; pseudostoma 23.02μm

Arcella hemisphaerica, Perty, 1852, Figure 3.11a-11b.

Deflandre (1928: 212-214), Figure 107-121; Grospietsch (1958: 39), Figure 24.a; Vucetich (1973: 289), Figure 1); Lansac-Tôha et al. (2008: 181, pl. 1), Figure 5.

Remarks: Lateral face, hemispherical shell that may have invaginated buccal tube. Ventral face, circular shell. Pseusostoma circular, small, with collarette around the aperture.

Size: (n=5). Shell width 65.03-63.21μm; shell height 45.87-44.71μm; pseudostoma 14.52-13.31μm.

Arcella hemisphaerica var. gibba Deflandre, 1928, Figure 3.12a-12b.

Deflandre (1928: 216), Figure 141-148; Souza (2008: 76), Figures a-b.

Remarks: Lateral face, hemispherical shell forming a slightly folded edge at the basal portion. Ventral face, circular shell with pseudostoma circular and centered.

Size: (n=3). Shell width 70.86-68.33μm; shell height 63.84-52.14μm; pseudostoma 16.64-15.23μm.

Arcella hemisphaerica var. intermedia undulata, Deflandre, 1928, Figure 3.21a-21b.

Deflandre (1928: 215), Figures. 128-137.

Remarks: Lateral face, hemispherical shell, with ripples throughout the shell, presence of invaginated buccal tube and string. Ventral face, circular and irregular shell, with pseudostoma circular and centered. Although the study of Tsyganov and Mazei (2006) has described this subspecies as a new one, entitled Arcella intermedia (Deflandre, 1928), the initial classification prevails.

Size: (n=1). Shell width 73.34μm; shell height 57.97 μm; pseudostoma 13.28μm.

Arcella hemisphaerica var. playfariana Deflandre, 1928 Figure 3.13a-13b.

Deflandre (1928: 215), Figures 128-137.

Remarks: Lateral face, hemispherical shell, narrower at the basal region, forming a border, invaginated buccal tube and collarette. Ventral face, circular shell with pseudostoma circular and centered. This is the first record of this subspecies in Brazil.

Size: (n=4). Shell width 76.57-67.83μm; shell height 65.82-49.60μm; pseudostoma 14.95-13.01μm. This is a new record in Brazil.

Arcella hemisphaerica var. undulata Deflandre, 1928 Figure 3.14a-14b.

Deflandre (1928: 214), Figures 122-124; Vucetich (1972: 272-273, pl. I), Figure 7; Vucetich (1973: 290, pl. I), Figure. 3; Souza (2008: 77), Figures. a-c.

Remarks: Lateral face, hemispherical shell with small and regular undulations, forming pits. Ventral face, circular shell, pseudostoma circular and centered.

Size: (n=6). Shell width 70.88-52.19μm; shell height 52.92-36.73μm; pseudostoma 21.61-11.89μm.

Arcella megastoma Pénard 1902 Figure 3.16a-16b.

Deflandre (1928: 267-268), Figures 363-372); Vucetich (1973: 298), Figure 18; Velho et al. (1996: 43, pl. II), Figure 14; Lansac-Tôha et al. (2008: 181, pl.1), Figure 6; Souza (2008: 75), Figure a.

Remarks: Lateral face, discoid shell, with invaginated buccal tube. Ventral face, circular shell, circular pseudostoma, invaginated and of large diameter.

Size: (n=8). Shell width 230.08-194.61μm; shell height 63.30-30.67μm; pseudostoma 116.98-99.32μm.

Arcella mitrata Leidy, 1879 (Figure 3.17a-17b)

Deflandre (1928: 270-271), Figure 376-385; Vucetich (1973: 298), Figure 19; Velho (1996: 37, pl. II), Figure 12; Souza (2008: 72), Figures a-c;

Remarks: Lateral face, shell oval and high, with invaginated buccal tube. Ventral face, circular shell with two concentric circles, the outer one corresponds to the junction of the buccal tube with the lateral shell and the inner one is the circular pseudostoma, which may present lobes, and centered.

Size: (n=3). Shell width 134.54-119.28μm; shell height 129.92-120.73-63.3μm; pseudostoma 39.62-37.36μm.

Arcella mitrata var. spectabilis Deflandre 1928 Figure 3.18a-18b.

Deflandre (1928: 273-274), Figures 388-391); Velho et al. (1996: 43, pl. II), Figure 13.

Remarks: Lateral face, oval shell, with high height and forming depressions, with invaginated buccal tube. Ventral face, circular shell with circular pseudostoma, centered, and collarette at the border.

Size: (n=7). Shell width 117.98-109.42μm; shell height 113.22-99.22μm; pseudostoma 35.17- 29.61μm.

Arcella rota Daday, 1905 (Figure 3.19a-19b)

Vucetich (1973: 296, pl. II) Figure 14; Velho (1996: 37, pl. II), Figure 10.

Remarks: Lateral face, discoid shell. Ventral face, circular shell with a number of small spines on the border of the shell.

Size: (n=1). Shell width 249.17μm; shell height 61.42μm; pseudostoma 99.63μm.

Arcella rotundata Playfair, 1917 (Figure 3.20a-20b)

Deflandre (1928: 233), Figure 223; Hardoin (1997:193), Figure 60.

Remarks: Lateral face, hemispherical shell, invaginated buccal tube starting at the lateral margin of the shell. Ventral face, circular shell with pseudostoma circular, centered.

Size: (n=4). Shell width 102.96-92.44μm; shell height 50.65-50.36μm; pseudostoma 24.08-20.22μm.

Arcella vulgaris Ehrenberg, 1830 (Figure 3.22a-22b).

Deflandre (1928: 219-221), Figure 156-164; Vucetich (1972: 274; 1973: 292, pl. I), Figure 6; Ogden & Hedley (1980: 44, pl. II), Figures a-d; Velho et al. (1996: 37, pl. I), Figure 1.

Remarks: Lateral face, hemispherical shell, domed, with a border in the basal portion of the shell. Ventral face, circular shell with pseudostoma circular, centered.

Size: (n=7). Shell width 174.91-173.25μm; shell height 81.60-63.45μm; pseudostoma 43.17-39.30μm.

Arcella vulgaris var. undulata, Deflandre 1928 (Figure 3.23a-23b)

Deflandre (1928: 221), Figures 165-170; Vucetich (1973: 292), Figure. 7; Velho et al. (1996: 37, pl. I), Figure 2; Souza (2008: 74), Figures a-b; Lansac-Tôha et al. (2008: 181, pl.1), Figure 8.

Remarks: Lateral face, hemispherical shell, edge with projections similar to a short border, surface with pits. Ventral face, circular shell. Pseudostoma circular, small, collarette around the aperture.

Size: (n=5). Shell width 93.14-90.76μm; shell height 66.57-41.04μm; pseudostoma 32.93-20.79μm.

The first characteristics used for the main division and classification of 23 taxa of Arcella in pictorial key were pseudostoma form (lobes or circular) and the position of the buccal tube (internal or external). To highlight the difference between some taxa with similar characteristics, we used proportion of shell measurements (Figure 4 and 5).

Discussion

The data obtained in this study report the first records of testate amoebae in the Paranoá Lake. Despite this environment aquatic microbiota have already been investigated (Pinto-Coelho & Giani, 1985; Padovesi-Fonseca, Galvão, & Rocha, 2002; Elmoor-Loureiro, Mendonça-Galvão, & Padovesi-Fonseca, 2004; Padovesi-Fonseca, Philomeno, & Andreoni-Batista, 2009), knowledge about the biological record of testate amoebae are scarce or nonexistent (Dabés & Velho, 2001; Lansac-Tôha, Zimmermann-Callegari, Alves, Velho, & Fulone, 2007; Schwind, Dias, Joko, Bonecker, & Lansac-Tôha, 2013).

Among the taxa found and given that this study considered the morphological variations of organisms, we highlight first records of A. excavata, and two more species, A. dentata var. trapezica, and A. hemisphaerica var. playfariana. Besides these, there was a record of species low incidents in Brazilian ecosystems, such A. rota (Velho et al., 1996; Alarcão et al., 2014; Maia-Barbosa, Menedez, Pujoni, Aoki, & Barbosa, 2014) and A. catinus (Rolla, Dabés, França, & Ferreira, 1992; Oliveira & Hardoim, 2010).

In this way, our results show a high richness of Arcella compared to other studies in the Center West region of Brazil (Lansac-Tôha et al., 2007; Takahashi, Lansac-Tôha, Dias, Bonecker, & Velho, 2009; Alarcão et al., 2014), confirming the importance of studies about the record of these protozoa in the Paranoá Lake. In addition, this pioneering study in Paranoá lake showed similar wealth values for environments that have more studies, for example, in the Upper Paraná River floodplain (21 taxa of Arcella) (Velho et al., 1996; Alves et al., 2007), Lansac-Tôha, Bonecker, Velho, Simões, Dias, Alves, & Takahashi, 2009; Lansac-Tôha, Velho, Costa, Simões, & Alves, 2014) and the Middle Doce River basin (21 species of Arcella) (Maia-Barbosa et al., 2014).

The high species richness found in this study may be associated the structuring of the sampled environments caused by marginal vegetation. The areas along the margin of the lake encompasses a variety of microhabitats (Kuczynska-Kippen, 2005; Meerhoff et al., 2007; Esteves, 2011). This condition could favor the biological richness of testate amoebae (Schwind et al., 2016); Fulone et al., 2005), justifying the rise of taxa recorded in studies on the littoral area (Souza, 2008; Maia-Barbosa et al., 2014).

Moreover, the identification of infraspecific taxa can be considered another factor that influenced the record of the expressive richness of testate amoebae in this environment. It is known that some authors do not recognize variations in species, as they may be reflection of taxonomic problems caused by morphological variability (Bobrov & Mazei, 2004; Smith, Bobrov & Lara, 2008). Nevertheless, this study opted for identification of infraspecific taxa (Splitting method), considering that morphological variations may help future studies of taxonomic revision, as seen for example in Tsyganov and Mazei (2006), which suggest changing A. hemisphaerica var. intermedia undulata to Arcella intermedia.

The description of testate amoebae species provides more details of their morphological characteristics, which may ultimately confound the identification of specimens by unfamiliar professional and/or students (Walter & Winterton, 2007). In this case, the pictorial key represents an effective tool, as it shows visually and in a comparative way the used characteristics. However, it is noteworthy that the selection of these critical characteristics was based on the differentiation of species found in the studied environment, since there is no standardization in the literature in the elaboration of these tools.

Conclusion

This study showed detailed taxonomic data of Arcella, which, through the use of the pictorial key, sought facilitate the identification of testate amoebae species and provide a basis for comparison of taxa in the Paranoá lake with other environments. Thus, the identification at the infraspecific level, adopted herein, provides a more accurate description of morphological variations of the taxa, which may assist works of taxonomic revision in other aquatic ecosystems.

Furthermore, the species richness recorded in this environment suggests that the Midwest region of Brazil can contain a great diversity of testate amoebae in aquatic environments. Therefore, this study highlights the need to increase researches with protozoa in this region.

References

Adl, S. M., Simpson, A. G. B., Lane, C. E., Lukes, J., Bass, D., Bower, S. S., Brown, M. W. & Spiegel, F. W. (2012). The revised classification of Eukaryotes. Journal Eukaryotic of Microbiology, 59(5), 429-514.

Alarcão, A. G., Sena-Souza, J. P., Maciel, B. L. O., Souza, C. A. & Kisaka, T. B., Santana, J. F. Vieira, L. C. G. (2014). A relevância de múltiplos grupos zooplanctônicos para o monitoramento ambiental no cerrado: estudo da estação ecológica Águas Emendadas. Espaço e Geografia, 17(1), 1-17.

Alves, G. M., Lansac-Tôha, F. A., Velho, L. F. M., Joko, C. Y., & Costa, D. M. (2007). New records of testate amoebae (Protozoa: Testacealobosea) for Upper Paraná River floodplain. Acta Limnologica Brasiliensia, 19(1), 175-195.

Arrieira, R. L., Alves, G. M., Schwind, L. T. F., & Lansac-Tôha, F. A. (2015). Local Factors Affecting the Testate Amoeba Community (Protozoa: Arcellinida; Euglyphida) in a Neotropical Floodplain. Journal of Limnology, 75(1), 23-40.

Bobrov, A., & Mazei, Y. (2004). Morphological Variability of Testate Amoebae (Rhizopoda: Testacealobosea: Testaceafilosea) in Natural Populations. Acta Protozoologica, 43(1), 133-146.

Cavalier-Smith, T., Chao, E. E. Y., & Oates, B. (2004). Molecular phylogeny of Amoebozoa and the evolutionary signicance of the unikont Phalansterium. European Journal Protistology, 40(1), 21-48.

Cunha, A. M. (1913). Contribuição para o conhecimento da fauna de protozoários do Brasil. Memórias do Instituto Oswaldo Cruz, 5(2), 101-122.

Dabés, M. B. G. S., & Velho, L. F. M. (2001). Assemblage of testate amoebae (Protozoa, Rhizopoda) associated to aquatic macrophytes stands in a marginal lake of the São Francisco river floodplain, Brazil. Acta Scientiarum Biological Sciences, 23(2), 415-422.

Deflandre, G. (1928). Le genre Arcella Ehrenberg. Morphologie-Biologie. Essai phylogénétique et systématique. Archiv fur. Protistenkunde, 64(2), 152-287.

Elmoor-Loureiro, L. M. A., Mendonça-Galvão, L., & Padovesi-Fonseca, C. (2004). New cladoceran records from lake Paranoá, central Brazil. Brazilian Journal of Biology, 64(3), 415-422.

Escobar, J., Brenner, M., Whitmore, T. J., Kenney, W. F., & Curtis, J. H. (2008). Ecology of testate amoebae (thecamoebians) in subtropical Florida lakes. Journal of Paleolimnology, 40(2), 715-731.

Esteves, F. A. (2011). Fundamentos de limnologia (3a ed.). Rio de janeiro-RJ: Interciência.

Ferrante, J. E. T., Rancan, L., & Netto, P. B. (2001). Meio físico. In Fonseca, F.O. Olhares sobre o lago Paranoá (p. 45-79). Brasília, DF: Secretaria de meio ambiente e recursos de meios hídricos.

Ferrer, G. G., & Del Negro, G. (2012). Unidade de Conservação Ambiental da Bacia do Lago Paranoá. Revista de estudantes de direito da UNB, 10(1), 365-399.

Fulone, L. J., Vieira, L. C. G., Velho, L. F. M., & Lima, A. F. (2005). Composição de amebas testáceas (Protozoa- Rhizopoda) de dois córregos do Estado de São Paulo, incluindo novos registros para o Brasil. Acta Scientiarum Biological Sciences, 27(2), 113-118.

Grospietsch, T. (1954). Die testaceen Rhizopoden der Hochmoore und ihre Bedeutung für die Moorforschung. Gewässer und Abwässe, 6(1), 5-19.

Grospietsch, T. (1958). Beiträge zur Rhizopodenfauna Deutschlands. I. Die The Kaniöben der Rhön. Hydrobiologia, 10(1), 305-322.

Grospietsch, T. (1972). Protozoa: A. Testacea und Heliozoa. In H. J. Elster, & W. Ohle Das Zooplankton der Binnengewässer (p. 1-30). Stuttgart-BW: Schweizerbart.

Kuczynska-Kippen, N. (2005). On body size and habitat selection in rotifers in a macrophye-dominated lake Budzynskie, Poland. Aquatic Ecology, 39(1), 447-454.

Lahr, D. J. G., & Lopes, S. G. B. C. (2009). Evaluating the taxonomic identity in four species of the lobose testate amoebae genus Arcella Ehrenberg, 1832. Acta Protozoologica, 48(2), 127-142.

Lansac-Tôha, F. A., Velho, L. F. M; Zimmermann-Callegari, M. C., & Bonecker, C. C. (2000). On the occurrence of testate amoebae (Protozoa, Rhizopoda) in Brazilian inland waters. I. Family Arcellidae. Acta Scientiarum. Biological Sciences, 22(2), 355-363.

Lansac-Tôha, F. A., Alves, G. M., Velho, L. F.M.; Robertson, B. A., & Joko, C. Y. (2008). Composition and occurrence of testate amebae in the Curuá-Una Resorvoir (State of Pará, Brazil). Acta Limnologica Brasiliensia, 20(3), 177-195.

Lansac-Tôha, F. A., Velho, L. F. M., Costa, D. M., Simões, N. R., & Alves, G.M. (2014). Structure of the Testate Amoebae Community in Different Habitats in a Neotropical Floodplain. Brazilian Journal of Biology, 74(1), 181-190.

Lansac-Tôha, F. A., Zimmermann-Callegari, M. C., Alves, G. M., Velho, L. F. M., & Fulone, L. J. (2007). Species richness and geographic distribution of testate amoebae (Rhizopoda) in Brazilian freshwater environments. Acta Scientiarum. Biological Sciences, 29(1), 185-195.

Lansac-Tôha, F. A.; Bonecker, C. C., Velho, L. F. M., Simões, N. R., Dias, J. D., Alves, G. M., & Takahashi, E. M. (2009) Biodiversity of zooplankton communities in the Upper Paraná River floodplain: interannual variation from long-term studies. Brazilian Journal of Biology, 69(1), 539-549.

Maia-Barbosa, P. M. M., Menedez, R. M., Pujoni, D. G. F., Aoki, A., & Barbosa, F. A. R. (2014). Zooplankton (Copepoda, Rotifera, Cladocera and Protozoa: Amoeba Testacea) from natural lakes of the middle Rio Doce basin, Minas Gerais, Brazil. Biota Neotropica, 14(1), 1-20.

Mattos, S. P., Altafin, I. G., Freitas, H. J., Cavalcanti, C. G., & Alvez, V. R. E. (1992). Integrated management plant for its restoration. Watter Poll, 27(1), 271-286.

Meerhoff, M., Iglesias, C., Mello, F. T., Clemente, J. M., Jensen, E., Lauridsen, T. L., & Jeppsen, E. (2007). Effects of habitat complexity on community structure and predator avoidance behaviour of littoral zooplankton in temperate versus subtropical shallow lakes. Freshwater Biology, 52(1), 1009-1021.

Meisterfeld, R. (2002). Order Arcellinida Kent, 1880. In J. J. Lee, G. F. Leedle, & P. Bradbury. An illustrated guide to the protozoa (p. 827-860). Society of Protozoologists. Lawrence-KS: Allen Press.

Mitchell, E. A. D., & Meisterfeld, R. (2005). Taxonomic confusion blurs the debate on cosmopolitanism versus local endemism of free-living protists. Protist, 156(1), 263-267.

Nikolaev, S. I., Mitchell, E. A. D., Petrov, N. B., Fahrni, J., & Pawlowski, J. (2005). The testate lobose amoebae (Order Arcellinida Kent, 1880) finally find their home within Amoebozoa. Protist, 156(1), 156-191.

Ogden, C. G., & Hedley, R. H. (1980). An atlas of freshwater testate amoebae. Oxford-UK: University Press.

Oliveira, T. M., & Hardoim, L. E. (2010). Study of testacean assemblages (Protozoa: Rhizopoda) in touristic waterfall regions of Chapada dos Guimarães National Park, Mato Grosso State, Brazil. Acta Scientiarum. Biological Sciences, 32(4), 387-395.

Oliveira, O. M. P., Mianzan, H., Migotto, A. E., & Marques, A. C. (2007). Chave de identificação dos Ctenophora da costa brasileira. Biota Neotropical, 7(3), 341-350.

Padovesi-Fonseca, C., Galvão, M. L., & Rocha, D. L. P. (2002). Temporal fluctuation ad reproduction of thermocyclops decipiens (Copepoda, Cyclopoida) in an eutrophic lake of central Brazil. Revista Biologia Tropical, 50(1), 57-68.

Padovesi-Fonseca, C., Philomeno, M. C., & Andreoni-Batista, C. (2009). Limnological features after a flushing event in Paranoá Reservoir, central Brazil Características limnológicas após um ‘flushing’ no Reservatório Paranoá, Brasil central. Acta Limnologica Brasiliensia, 21(3), 277-285.

Panarelli, E., Casanova, S. M. C., Nogueira, M. G., Mitsuka, P. M., & Henry, R. (2003) A comunidade zooplanctônica ao longo de gradientes longitudinais no Rio Paranapanema/Represa de Jurumirim (São Paulo, Brasil). In R. Henry. Ecótonos nas interfaces dos ecossistemas aquáticos (p. 129-160). São Paulo-SP: Rima.

Pénard, E. (1890). Études sur les Rhizopodes d’eau douce. Mémorias de lá Société de Physique d’ Histoire Naturelle de Géneve, 31(1), 1-230.

Pimpão, D. M., & Mansur, M. C. D. (2009). Chave pictórica para identificação dos bivalves do baixo Rio Aripuanã, Amazonas, Brasil (Sphaeriidae, Hyriidae e Mycetopodidae). Biota Neotropical, 9(3), 377-384.

Pinto-Coelho, R. M., & Giani, A. (1985). Variações sazonais do fitoplâncton e fatores físico-químicos da água no reservatório do Paranoá, Brasília, DF. Ciência e Cultura, 37(12), 2000-2006.

Porter, S. M., & Knoll, A. H. (2000). Testace amoebae in the Neoprotozoia Era: evidence from vase-shaped microfossils in the Chuar Group, Gram Cayon. Paleobiology, 26(3), 360-385.

Rhoden, R., & Pitoni, V. L. L. (1999). Amebas testaceas (Protista, Sarcomastigophora, Rhizopoda) em Sphagnum recurvo P.Beauev e Sphagnum perichartiale Hampe (turfeira), no município de São Francisco de Paula, Rio Grande do Sul, Brasil. Biociências, 7(1), 91-120.

Rolla, M. E., Dabés, M. B. G. S., França, R. C., & Ferreira, E. M. V. M. (1992). Inventário limnológico do rio Grande na área de influência da futura usina hidrelétrica (UHE) de Igarapava. Acta Limnologica Brasiliensia, 1(1), 139-162.

Schwind, L. T. F., Dias, J. D., Joko, C. Y., Bonecker, C. C., & Lansac-Tôha, F. A. (2013). Advances in studies on testate amoebae (Arcellinida and Euglyphida): a scientometric approach. Acta Scientiarum. Biological Sciences, 35(4), 549-555.

Schwind, L. T. F., Arrieira, R. L., Dias, J. D., Simões, N. R., Bonecker, C. C., & Lansac-Tôha, F. A. (2016). The structure of planktonic communities os testate amoeba (Arcellinida and Euglyphida) in three environments of the Upper Paraná River basin, Brasil. Journal of limnology,75(1), 78-89.

Smith, H., Bobrov, A., & Lara, E. (2008). Diversity and biogeography of testate amoebae. Biodiversity and Conservation, 17(2), 329-343.

Souza, G. M. B. (2008). Guia das tecamebas - bacia do rio Peruaçu- Minas Gerais: subsídio para conservação e monitoramento da bacia de rio São Francisco. Belo Horizonte-MG: UFMG.

Takahashi, E. M.; Lansac-Tôha, F. A., Dias, J. D., Bonecker, C. C., & Velho, L. F. M. (2009). Spatial variations in the zooplankton community from the Corumbá Reservoir, Goiás State, in distinct hydrological periods. Acta Scientiarum. Biological Sciences, 31(3), 227-234.

Tsyganov, A., & Mazzei, Y. (2006). Morphology and biometry of Arcella intermedia (Deflandre, 1928) comb. nov. from Russia and a review of hemispheric species of the genus Arcella (Testcealobosea, Arcellinida). Protistology, 4(1), 361-369.

Velho, L. F. M., Lansac-Tôha, F. A., & Serafim-Júnior, M. (1996). Testate amoebae (Rhizopodea-Sarcodina) from zooplankton of the high Paraná river floodplain, state of Mato Grosso do Sul, Brazil: I. Families Arcellidae and Centropyxidae. Studies Neotropical Fauna and Environment, 31(1), 35-50.

Vucetich, M. C. (1972). Tecamebianos del Eupleuston de cuerpos de Agua de la Provincia de Buenos Aires. Acta Zoologica Lilloana, 29(1), 272-284.

Vucetich, M. C. (1973). Estudio de tecamebianos argentinos, en especial los del dominio pampasico. Revista del Museu de La Plata, 1(108), 287-332.

Walter, D. E., & Winterton, S. (2007). Keys and the Crisis in Taxonomy: Extinction or Reinvention? Annual Review of Entomology, 52(1), 193-208.

Author notes

marianalessac@gmail.com

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