Phylogenetic evidence for a new genotype of Acanthamoeba (Amoebozoa, Acanthamoebida)

Acanthamoeba are widespread free-living amoebae, able to cause infection in animals, with keratitis and granulomatous encephalitis as major diseases in humans. Recent developments in the subgenus classification are based on the determination of the nucleotide sequence of the 18S rDNA. By this mean, Acanthamoeba have been clustered into 15 sequence types or genotypes, called T1 to T15. In this study, we analysed near full 18S rDNA of an Acanthamoeba recovered from an environmental sample and various unidentified Acanthamoeba sequences retrieved from GenBank. We provided phylogenetic evidence for a new genotype, which we proposed to name T16.