title: Sexual differences in prevalence of a new species of trypanosome infecting túngara frogs.
abstract: Trypanosomes are a diverse group of protozoan parasites of vertebrates transmitted by a variety of hematophagous invertebrate vectors. Anuran trypanosomes and their vectors have received relatively little attention even though these parasites have been reported from frog and toad species worldwide. Blood samples collected from túngara frogs (Engystomops pustulosus), a Neotropical anuran species heavily preyed upon by eavesdropping frog-biting midges (Corethrella spp.), were examined for trypanosomes. Our results revealed sexual differences in trypanosome prevalence with female frogs being rarely infected (<1%). This finding suggests this protozoan parasite may be transmitted by frog-biting midges that find their host using the mating calls produced by male frogs. Following previous anuran trypanosome studies, we examined 18S ribosomal RNA gene to characterize and establish the phylogenetic relationship of the trypanosome species found in túngara frogs. A new species of giant trypanosome, Trypanosoma tungarae n. sp., is described in this study. Overall the morphometric data revealed that the trypomastigotes of T. tungarae n. sp. are similar to other giant trypanosomes such as Trypanosoma rotatorium and Trypanosoma ranarum. Despite its slender and long cell shape, however, 18S rRNA gene sequences revealed that T. tungarae n. sp. is sister to the rounded-bodied giant trypanosome, Trypanosoma chattoni. Therefore, morphological convergence explains similar morphology among members of two non-closely related groups of trypanosomes infecting frogs. The results from this study underscore the value of coupling morphological identification with molecular characterization of anuran trypanosomes.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA; Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Panama.
authors.forename: Ximena E
authors.initials: XE
authors.lastname: Bernal
authors.affiliation: Sackler Institute for Comparative Genomics and Department of Mammalogy, American Museum of Natural History, New York, NY, 10024, USA; Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador; Division of Mammals, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20004, USA.
authors.forename: C Miguel
authors.initials: CM
authors.lastname: Pinto
keywords: Corethrella; Engystomops pustulosus; Frog-biting midges; Panamá; Physalaemus; Species delimitation; Trypanosome phylogeny