First report of molecular characterization and phylogeny of Trichuris fossor Hall, 1916 (Nematoda: Trichuridae)

Because species of Trichuris are morphologically similar and ranges of host preference are variable, using molecular data to evaluate species delineations is essential for properly quantifying biodiversity of and relationships within Trichuridae. Trichuris fossor has been reported from Thomomys spp. (Rodentia: Geomyidae, ‘pocket gophers’) hosts based on morphological features alone. Partial 18S rRNA sequences for specimens identified as T. fossor based on morphology, along with sequences from 26 additional taxa, were used for a phylogenetic analysis. Evolutionary histories were constructed using maximum likelihood and Bayesian inference. In both analyses, the specimens fell within the Trichuris clade with 100% support and formed a distinct subclade with 100% support. These results confirm that T. fossor is a distinct species and represent the first molecular report for it. Relatedness among species within the family were well resolved in the BI tree. This study represents an initial effort to obtain a more comprehensive view of Trichuridae by including a new clade member, T. fossor. A better understanding of Trichuridae phylogeny could contribute to further characterization of host-associations, including species that infect livestock and humans.