Genus Ovalopodium Sawyer, 1980

 

Diagnosis: amoeba broadly discoid or spherical in shape with a central or post-central hump and spine-like posterior uroidal filaments; cell completely surrounded by a more or less distinctive hyaline margin, smooth or rippled, without subpseudopodia; cytoplasm granular with numerous clear vesicles; nucleus vesicular, with a large nucleolus.

 

Ecology: marine

 

Type species: Ovalopodium carriikeri Saywer, 1980.

 

 

Ovalopodium desertum Kudryavtsev, Wylezich and Pawlowski, 2011

 

Diagnosis: Amoeba resembles a small Cochliopodium in the light microscope, but has a dorsal fibrous cell coat without scales.

Ecology: weakly saline semi-desert pond in Kazakhstan

Remarks: Phylogenetic analysis of the SSU rRNA gene sequences of the new species and four Cochliopodium spp. sequenced additionally shows that Ovalopodium desertum is a sister clade to a robustly monophyletic Cochliopodium. The close relationship between Ovalopodium and Cochliopodium is also confirmed by the analysis of SSU rRNA secondary structure showing the specific helices in the region V5 in all species of both genera. Analysis of actin gene sequences fails to resolve the position of Ovalopodium but demonstrates that Parvamoeba Rogerson, 1993 is probably related to Cochliopodium. The position of Cochliopodiidae within Amoebozoa remains unresolved, despite our efforts to resolve it using broader taxonomic sampling of Amoebozoa, testing alternative tree topologies and removing the fast-evolving sites. Among sequenced genera, Parvamoeba and Endostelium Olive et al., 1984 are probable relatives to Cochliopodiidae. Molecular trees weakly support an inclusion of the family in Flabellinia (Discosea), but more phylogenomic data are necessary to test this hypothesis (Kudryavtsev et al, 2011)