SSUrDNA analysis reveals the existence of a second Naegleria sp with dividing flagellates:: N-robinsoni sp nov.

A new vahlkampfiid amoeboflagellate that forms flagellates which can divide has been isolated from freshwater on Kangaroo Island in Australia. It was deduced from partial small subunit ribosomal DNA (SSUrDNA) sequence comparisons that the isolate belongs to the genus Naegleria. The SSUrDNA sequence of the new isolate (strain NG944) differs by 2.4% from its closest relative, N. galeacystis, The ribosomal internal transcribed spacer region 1 (ITS1) sequence of strain NG944 is identical to that of the reference strain of N. galeacystis, while there are two base pair differences between them within the 175 bp of the 5.8S rDNA sequence. Both strains have shore inserts within the ITS2 which differ by 26%, Strain NG944 is described as a new species: N. robinsoni. This is only the second species of the genus Naegleria in which dividing flagellates have been observed; the flagellates of the other 15 described Naegleria spp. do nor divide. In the family Vahlkampfiidae, the loss of the ability to divide in the flagellate stage seems to be unique to the genus Naegleria as in all the other vahlkampfiid species in which the amoebae can differentiate into flagellates these flagellates have the ability to divide.