![]() ![]() The evolutionary relationships among genera and species within Amoebozoa continue to be controversial (e.g. Establishment of robust phylogenetic relationships among taxa is necessary if we are to rely on testate amoebae as bioindicators (Gomaa et al., 2012, Payne, 2011). Additionally, recent studies have assessed the relationship between testate amoeba abundance and changing environmental conditions (Chapman et al., 2003, Tsyganov et al., 2012). ![]() For instance, testate amoebae are relied upon to reconstruct paleoenvironmental conditions (Elliott et al., 2012, Mitchell et al., 2008, Warner and Charman, 1994). Testate amoebae are regarded as important biological indicator species and commonly used as monitors of environmental variability (Lamentowicz et al., 2011, Sullivan and Booth, 2011). These microbes are found commonly in soils, leaf-litter, mosses and freshwater habitats (Meisterfeld 2002). One clade of mostly uncultured microbes is the lobose testate (shelled) amoebae (Amoebozoa: Arcellinida). Schmeisser et al., 2007, Torsvik and Ovreas, 2002), making it challenging to estimate levels of genetic diversity and the ecological role of microbes within ecosystems (Curtis and Sloan, 2004, Staley, 2010). Very little of this diversity is culturable (e.g. ![]() Microbes are found almost everywhere in nature and comprise a majority of the Earth's biomass and biodiversity (e.g. Our results suggest the morphological plasticity of testate amoebae across evolutionary time scales and that a combination of morphology and molecular analyses is needed to understand the biodiversity of these taxa. Moreover, inclusion of up to 24 specimens per species indicates non-monophyly of the morphospecies Hyalosphenia papilio and Hyalosphenia elegans. Our analyses confirm this pattern and further suggest that other Nebela genera and morphospecies are not monophyletic. Previous SSU-rDNA work on a limited sample of these species showed non-monophyly in the genus Hyalosphenia. An SSU-rDNA phylogeny including 20 specimens from GenBank and 63 from this study reveals diversity within and among morphospecies and low resolution among some Nebela spp. Here, we assess the biodiversity and relationships among eight morphospecies: Hyalosphenia elegans, Hyalosphenia papilio, Nebela carinata, Nebela flabellulum, Nebela militaris, Nebela tincta, Nebela tubulosa, and Quadrulella symmetrica using small subunit ribosomal DNA (SSU-rDNA). The recent application of molecular tools has revealed a greater complexity than morphology suggests, including multiple cryptic species. siliceous, proteinaceous, agglutinated, or even calcareous). Test morphology is standardly used to identify morphospecies as tests have varying shapes and compositions (e.g. Test ovoid or elongated elliptic, L/B = 1.3–1.Testate (shelled) amoebae are abundant and diverse in Sphagnum -rich areas of bogs and fens. With short neck (4.6 ± 0.2 high), with linear wide aperture 24–26 µm With protruding neck and narrow aperture 19–23 µm, up twisted Test without lateral ridge, pyriform, with very short (2.7 ± 0.9 µm high or almost absent) neck, with aperture slightly or strongly curved, or sometimes linear, 28–32 µm Test with lateral ridge, wide ovoid, with wide linear aperture 24–27 µm 90–133 µm, strongly flattened, with short neck Key to the Nebela collaris-tincta group 1 Granoreticulose – Naked amoeboid organisms with branched filopodia over which numerous granules move extremely quickly in both directions and which can form an extensive network (reticulum).Pseudopodia usually appressed to the substratum. Granules are evenly distributed and move slowly or not at all. Granofilose – Naked amoeboid organisms with granular filose pseudopodia.Filose – Naked amoeboid organisms with filamentous pseudopodia.Some species have subpseudopodia, small extensions of a hyaline anterior zone. Lobose – Naked amoebae with finger-shaped, tubular pseudopodia.Granuloreticulose – Testate amoeboid organisms with branched filopodia over which numerous grains move extremely quickly in both directions and which can form an extensive network (reticulum).Test and pseudopodia appressed to the substratum. Granofilose – Testate amoeboids with granular filose pseudopodia.Filose – Testate amoebae with filose (filamentous) pseudopodia.Lobose – Testate amoebae with finger-shaped, tubular pseudopodia. ![]()
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