Paravannella minima n. g. n. sp. (Discosea, Vannellidae) and distinction of the genera in the vannellid amoebae.
Paravannella minima n. g. n. sp. (Amoebozoa, Vannellidae) isolated from a freshwater aquarium, possesses all light-microscopic and ultrastructural characteristics of the genus Vannella, being one of the smallest species among the vannellid amoebae (cell size during locomotion usually between 4.5 and 10μm). At the same time, sequence analysis of the genes encoding for nuclear SSU rRNA, actin and mitochondrial Cox1 shows this species as the earliest-branching vannellid that appears to be sister to the rest of this clade. This is correlated with the presence of some plesiomorphic characters; in particular, the secondary structure of the hypervariable helices E23-1-E23-7 in the studied species is shared with Vannella and most of the genera of Dactylopodida. The cell coat structure of the studied species corresponds to the hypothesis that vannellid amoebae were ancestrally enclosed in a cell coat consisting of pentagonal glycostyles that have undergone multiple independent losses in various clades of Vannellidae.
Department of Invertebrate Zoology, Faculty of Biology and Soil Science, St-Petersburg State University, Universitetskaja nab. 7/9, 199034 St-Petersburg, Russia. Electronic address: a.kudryavtsev@bio.spbu.ru.
Alexander
A
Kudryavtsev
D000656:Amoeba / Q000145:classification* / Q000166:cytology / Q000235:genetics / Q000648:ultrastructure; D005618:Fresh Water / Q000469:parasitology; D017125:Genes, Protozoan / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D013045:Species Specificity
D012337:RNA, Ribosomal, 18S
Amoebozoa; Molecular phylogeny; Paravannella minima n. g. n. sp.; Taxonomy; Ultrastructure; Vannellidae