Phylogeny and taxonomy of new and re-examined strains of Tubulinea (Amoebozoa)

Morphological and molecular characterizations of three newly isolated tubulinean strains and re-examination of five strains formerly considered representatives of Saccamoeba and one strain formerly considered as Trichamoeba resulted in (a) the determination of strain BA02, isolated from a dripping rock ledge in Skansbukta (Billefjorden, Svalbard), as a new representative of Ptolemeba bulliensis Brown et al., 2014; (b) identification of strain ATCC® 50249™, deposited in the American Type Culture Collection as Trichamoeba, as the same species (P. bulliensis); (c) characterization of the new strain POHL into the Saccamoeba clade as a member closely related to S. lacustris; and (d) changing the generic residence of three strains formerly considered as representatives of Saccamoeba (strain PV67 to the P. bulliensis clade, and W187G and DP7 into the sister group of Ptolemeba noxubium Brown et al., 2014) whereas two other strains (MSED6, NTSHR) retain their original Saccamoeba clade position. Within the individual clades, the ultrastructure (especially the inner architecture of mitochondria) is congruent and thus of superior taxonomic value to that of light microscopic (morphometric) features.