A synopsis of cosmopolitan, rare and new Frustulia species (Bacillariophyceae) from ombrotrophic peat bogs and minerotrophic swamps in New Zealand
Beier, Tanja; Lange-Bertalot, Horst
Eight Frustulia taxa from lowland wetlands on the south-western coast of the New Zealand South Island were examined by light microscopy (LM) and scanning electron microscopy (SEM). Four taxa are described as new species. Frustulia aotearoa, which is distinguished from F. bahlsii Edlund & Brant, occurred exclusively in ombrotrophic peat bogs, whereas F. cassieae, F. gondwana, and F. maoriana were restricted to slightly acidic, minerotrophic swamps. Frustulia cassieae has been recorded in the past in eastern Australia and New Zealand's North Island but was erroneously identified as F. rhomboides var. elongatissima Manguin. Frustulia gondwana resembles populations from other regions of the southern hemisphere and the Neotropics. These populations, however, were not specified in detail. In contrast, F. maoriana has not been observed elsewhere and may provisionally, like F. aotearoa, be regarded as an endemic element of the New Zealand diatom flora. So far, F. pangaeopsis Lange-Bertalot was known only from Central Europe, but turns out to be cosmopolitan since its counterpart in the wetlands studied could not be differentiated from it by any of the observed morphological or ecological features. Conspecificity of F. magaliesmontana Cholnoky from South Africa with the New Zealand population remains questionable, however. In contrast to F. pangaeopsis, which is limited to highly acidic, ombrotrophic ecosystems, F. magaliesmontana occupies a wider ecological niche and is associated with the cosmopolitan species F. crassinervia (Brébisson) Lange-Bertalot and F. saxonica Rabenhorst.