| A survey and inventory of Guatemalan herpetofauna was conducted during 1998–2000. Almost 1500 hosts were collected and 573 were examined for eimeriid parasites. Ninety-one host individuals had Eimeria oocysts in the intestine. From these hosts, 29 new Eimeria species are described here, and a re-description and new geographic record is given for Eimeria lepidophyma Telford, 1998.; Molecular sequence data from 18S ribosomal DNA of a subset of 17 Eimeria species found in squamate reptiles was used in a phylogenetic analysis to determine if multiple lineages of reptile Eimeria could be defined by either host phylogeny or the morphology of the parasite's sporulated oocysts. It was found that these species form three clades, for which the phylogenetic relationship is defined by neither host phylogeny nor oocyst morphology. These data also indicate that Choleoeimeria is not a monophyletic group. Species with the oocyst morphology characteristic of Choleoeimeria and endogenous stages found within the gall bladder were shown to belong to two of these three clades.; Molecular sequence data from Eimeria and Goussia species infecting fish, amphibians, reptiles, birds, and mammals were used in a phylogenetic analysis to examine the evolutionary relationship between Eimeria and Eimeria-like species of these major vertebrate lineages. 18S rDNA sequences from Eimeria species from these reptiles and two Goussia species isolated from piscine hosts add considerably to the available molecular data which, to the present, had been collected almost entirely from coccidians of rodents and domestic animals. Three distinct lineages are formed by 13 reptile Eimeria and the Goussia species. These lineages are basal to the clade containing the other eimeriid species, including four reptile Eimeria. Divergence dates for these three lineages were approximated based on published dates for the divergence between Eimeriidae and Sarcocystidae, 500 million years ago (m.y.a.), and for the radiation of the Apicomplexans, 350–824 m.y.a. These data indicate that Eimeria species may have radiated with their reptile hosts during the Paleozoic and Mesozoic, undergoing several host switching events from reptiles into mammals and birds during the last 70–178 m.y. |
