20708961
not annotated - annotated - LINNAEUS only
Facing unknowns: living cultures (Pirum gemmata gen. nov., sp. nov., and Abeoforma whisleri, gen. nov., sp. nov.) from invertebrate digestive tracts represent an undescribed clade within the unicellular Opisthokont lineage ichthyosporea (Mesomycetozoea).
During a culture-based survey of opisthokonts living in marine invertebrate digestive tracts, we isolated two new eukaryotes that differed from described taxa by more than 10% in their small subunit ribosomal DNA sequences. Phylogenetic analysis showed that the two isolates represented a divergent clade of ichthyosporeans known previously only from environmental clone sequences. We used light and electron microscopy to describe the isolates as new genera and species Pirum gemmata and Abeoforma whisleri. A. whisleri had a complex life cycle that remains incompletely known but involved walled spherical cells, plasmodia and amoebae. Asexual reproduction occurred via dispersal amoebae, endospores, binary fission and budding. In contrast P. gemmata had a less complex life cycle with no amoeboid or plasmodial stages. Both species had membrane-bound tubular extensions of the cytoplasm embedded in the inner layers of their cell walls. By comparing P. gemmata and A. whisleri to other ichthyosporea we speculate on the characters that may have been present in the ancestral ichthyosporean. P. gemmata and A. whisleri illustrate the unique and diverse forms that can be found by capturing taxa belonging to divergent and uncultured lineages.
Ann file
T1 Species 34 47 Pirum gemmata
N1 Reference T1 Taxonomy:749231
T2 Species 73 91 Abeoforma whisleri
N2 Reference T2 Taxonomy:749232
T3 Species 728 741 Pirum gemmata
N3 Reference T3 Taxonomy:749231
T4 Species 746 764 Abeoforma whisleri
N4 Reference T4 Taxonomy:749232
T5 Species 766 777 A. whisleri
N5 Reference T5 Taxonomy:749232
T6 Species 1000 1010 P. gemmata
N6 Reference T6 Taxonomy:749231
T7 Species 1211 1221 P. gemmata
N7 Reference T7 Taxonomy:749231
T8 Species 1226 1237 A. whisleri
N8 Reference T8 Taxonomy:749232
T9 Species 1352 1362 P. gemmata
N9 Reference T9 Taxonomy:749231
T10 Species 1367 1378 A. whisleri
N10 Reference T10 Taxonomy:749232