A New Amoeba with Protosteloid Fruiting: Luapeleamoeba hula n. g. n. sp. (Acanthamoebidae, Centramoebida, Amoebozoa)

We describe a new protosteloid amoeba, Luapeleamoeba hula. Protosteloid amoebae, sometimes called protostelids, are sporocarpic amoebae that make fruiting bodies that consist of a stalk and one to a few spores. This new taxon was cultured from dead leaves of mamaki (Pipturus albidus) from the Manuka Natural Area Reserve, Hawaii, USA. Light microscopic examination showed that this amoeba has a short, rigid stalk with a small apophysis and a spore that changes shape continuously until it is shed and crawls away from the stalk. In addition, this amoeba was initially observed to maintain a diurnal rhythm in which fruiting body formation occurred primarily in the late afternoon. This new species is unique in both its amoebal and fruiting body morphology. Spore deciduousness appears to be a result of shape changes in the spore itself. This is the fourth species of protosteloid amoeba described with a clearly described diurnal rhythm. In addition, previous molecular phylogenetic analyses suggested that this new species has SSU rRNA gene sequences that clearly separate it from any other protosteloid amoebae and place it as sister to Protacanthamoeba bohemica among the Acanthamoebidae family in Centramoebida of Amoebozoa. Because this new amoeba species does not fit into any of the centramoebid genera, we have proposed a new genus Luapeleamoeba.