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Trypanosomatid diversity in Heteroptera was sampled using a culture-independent approach based on amplification and sequencing of Spliced Leader RNA gene repeats from environmental samples. By combining the data collected herein with that of previous work, the prevalence of parasites was found to be 22%-23%. Out of approximately 170 host species investigated nearly 60 were found to harbor trypanosomatids. The parasites found were grouped by cluster analysis into 48 typing units. Most of these were well separated from the known groups and, therefore, likely represent new trypanosomatid species. The sequences for each typing unit serve as barcodes to facilitate their recognition in the future. As the sampled host species represent a minor fraction of potential hosts, the entire trypanosomatid diversity is far greater than described thus far. Investigations of trypanosomatid diversity, host-specificity, and biogeography have become feasible using the approach described herein.

Leptomonas podlipaevi n. sp., a new trypanosomatid species, is described herein based on light microscopic, ultrastructural, and molecular phylogenetic data. The organism is pleomorphic both in host and culture, with two predominant forms-a typical promastigote with a long flagellum and a shorter promastigote with a small or barely extending flagellum. Several spliced leader RNA repeat sequences obtained from the original cultures and the clonal lines representing two types of cells were all nearly identical. These sequences formed a tight cluster in the neighbor-joining tree well separated from other trypanosomatid species. Glyceraldehyde phosphate dehydrogenase gene sequences were determined for L. podlipaevi and 10 previously described trypanosomatid species. Molecular phylogenetic analysis has demonstrated that the new species is most closely related to Leptomonas seymouri and Leptomonas pyrrhocoris. The analysis has also highlighted the polyphyly of the genus Leptomonas.

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