Related Experiment Video
Updated: Jun 25, 2026

Visualizing Bacteria in Nematodes using Fluorescent Microscopy
Published on: October 19, 2012
Phylogenetic Relationships Among Xiphinema and Xiphidorus Nematode Species from Brazil Inferred from 18S rDNA
Abstract:
Maximum likelihood trees produced from 18S rDNA sequences separated 14 Xiphinema and five Xiphidorus nematode species from Brazil into distinct groups that concurred with their current morphological taxonomic status. Species belonging to the X. americanum group (X. brevicolle, X. diffusum, X. oxycaudatum, and X. peruvianum) formed a single group that was clearly separated from the other Xiphinema species. As with previous taxonomic studies that noted only minor morphological differences between putative X. americanum group species, separation of these species based upon 18S rDNA sequences was inconclusive. Thus it is probable that instead of comprising distinct species, the X. americanum group may in fact represent numerous morphotypes with large inter- and intra- population morphological variability that may be environmentally driven. Within the cluster representing non X. americanum group species, there was little statistical support to clearly separate species. However, three subgroups, comprising (i) the X. setariae/vulgare complex, (ii) X. ifacolum and X. paritaliae, and (iii) X. brasiliense and X. ensiculiferum were well resolved.
Related Concept Videos
Evolutionary Relationships through Genome Comparisons
Diversity of Protists I
Microbial Phylogeny
Diversity of Protists III
Phylogeny
Phylogenetic Species Concept in Microbiology

