ABSTRACT Biogeography is known to have shaped the diversity and evolutionary history of avian haemosporidian parasites across the Neotropics. However, a paucity of information exists for the temperate Neotropics and especially from nonpasserine hosts. To understand the effect of biogeography in the temperate Neotropics on haemosporidians of nonpasserine hosts we screened ducks (Anseriformes) from central Chile for the presence of these parasites. Forty-two individuals of 4 duck species ( Anas flavirostris , Anas georgica , Mareca sibilatrix , Spatula cyanoptera cyanoptera ) were collected and assessed for haemosporidian parasite infections by real-time polymerase chain reaction screening and subsequent sequencing of the mitochondrial cytochrome b gene. Haemoproteus (subgenus Haemoproteus ) and Plasmodium were detected in 2 host species, A. georgica and S. c. cyanoptera , with no Leucocytozoon found. Overall haemosporidian prevalence was low (14.2%), with the prevalence of Plasmodium (11.9%) being substantially greater than that of Haemoproteus (4.8%). Six haemosporidian cytochrome b lineages were recovered, 2 Haemoproteus and 4 Plasmodium , with all 6 lineages identified for the first time. In phylogenetic reconstruction, the Chilean Plasmodium lineages were more closely related to South American lineages from passerine birds than to known lineages from anseriforms. The subgenus Haemoproteus known from nonpasseriformes has never been identified from any anseriform host; however, we recovered 2 lineages from this subgenus, one from each A. georgica and S. c. cyanoptera . Further work is needed to determine if this presents true parasitism in ducks or only a spillover infection. The results of phylogenetic reconstruction demonstrate a unique evolutionary history of these Chilean parasites, differing from what is known for this host group. The unique geography of Chile, with a large part of the country being relatively isolated by the Atacama Desert in the north and the Andes in the east and south, would present opportunities for parasite diversification. Further work is needed to investigate how strongly the biogeographical isolation has shaped the haemosporidian parasites of this area. Our results add to the growing body of evidence that nonpasserine hosts support unique lineages of haemosporidian parasites, while also demonstrating the role of biogeography in haemosporidian parasite diversity in the temperate Neotropics.

ABSTRACT Birds harbor a diverse group of haemosporidian parasites that reproduce and develop in the host blood cells, muscle tissue, and various organs, which can cause negative effects on the survival and reproduction of their avian hosts. Characterization of the diversity, distribution, host specificity, prevalence patterns, and phylogenetic relationships of these parasites is critical to the study of avian host–parasite ecology and evolution and for understanding and preventing epidemics in wild bird populations. Here, we tested whether muscle and liver samples collected as part of standard ornithological museum expeditions can be examined to study the diversity and distributions of haemosporidians in the same way as blood collected from individual birds that are typically banded and released. We used a standard molecular diagnostic screening method for mitochondrial DNA (cytochrome b ) of the parasites and found that blood, muscle, and liver collected from the same host individual provide similar estimates of prevalence and diversity of haemosporidians from the genera Parahaemoproteus and Leucocytozoon . Although we found higher prevalence for the genus Plasmodium when we screened blood vs. liver and muscle samples, the estimates of the diversity of Plasmodium from different tissue types are not affected at the community level. Given these results, we conclude that for several reasons existing museum genetic resources collections are valuable data sources for the study of haemosporidians. First, ornithological museum collections around the world house tens of thousands of vouchered tissue samples collected from remote regions of the world. Second, the host specimens are vouchered and thus host identification and phenotype are permanently documented in databased archives with a diversity of associated ancillary data. Thus, not only can identifications be confirmed but also a diversity of morphological measurements and data can be measured and accessed for these host specimens in perpetuity.

A new species, Crepidostomum affine n. sp., is described from Hiodon tergisus in Mississippi, and morphological data are provided for Crepidostomum auritum from Aplodinotus grunniens in Mississippi and for Crepidostomum illinoiense from Hiodon alosoides in Minnesota. The new species is most similar morphologically to C. illinoiense , but has a shorter intertesticular space, measuring 0–74 μm (mean = 19.3 ± 23.1 SD in 73 specimens) compared with 0–229 μm (mean = 57.3 ± 56.7 SD in 34 specimens), and the distance between the ovary and the anterior testis is relatively shorter in the new species, representing 2.6–7.9% of overall body length compared with 4.1–12.4% in C. illinoiense . Fragments of nuclear ribosomal as well as mitochondrial DNA are compared among C. affine n. sp., C. illinoiense , C. auritum and Crepidostomum cornutum . Crepidostomum affine n. sp. and C. illinoiense are most similar, having between 19 and 20 variable bases (1.29–1.36%) in the amplified nuclear ribosomal RNA fragment comprising the complete ITS2 spacer and partial 28S gene, and between 35 and 39 variable bases (8.62–9.61%) in the amplified fragment of the COI region. Specimens of C. illinoiense from the Missouri River in North Dakota and Red Lake River in Minnesota differed by 1 base (0.07%) in the rRNA fragment and 4 bases (0.95%) in COI fragment. Crepidostomum cornutum and C. auritum also have 19 (1.29%) variable bases in the amplified ITS2 and partial 28S regions and 50 (12.32%) variable bases in the amplified COI region. Both C. cornutum and C. auritum demonstrated much greater levels of differences compared to C. affine n. sp. These results add to previously published data reporting species of fish digeneans that might be endemic to the Pearl and Pascagoula river basins in Mississippi.