Biodiversity and Phylogenetics of Metazoan Parasites Infecting Freshwater Turtles

Abstract

There are 356 extant turtle species (Testudines), including 60 polytypic taxa that add 122 subspecies. Among the more diverse groups of metazoan parasites that infect turtles are the turtle blood flukes (TBFs) (Digenea: Schistosomatoidea; 106 species; 24 genera). Polystomes (Monogenoidea: Polystomatidae; 61 species; 5 genera) are another underexplored group of parasites infecting turtles. They belong to a much larger group of flatworms that are, nearly without exception, fish ectoparasites and are further intriguing by infecting unusual sites (conjunctival sac, buccal cavity, urinary bladder) of turtles and frogs. Both of these taxonomic groups are understudied in North America. TBFs, especially of freshwater turtles, are largely ignored outside of North America. TBFs and polystomes infect members of both major turtle lineages, sub-order Pleurodira Cope, 1864 (side-necked turtles, withdraw neck by bending in horizontal plane; 93 species) and sub-order Cryptodira Cope, 1868 (hidden-necked turtles, withdraw head by bending neck in vertical plane; 263 species). Extant cryptodires range in the northern and southern hemispheres, whereas extant pleurodires range in southern hemisphere freshwater habitats only. Herein, I necropsied 86 turtles of 24 species (14 genera: 7 families; including cryptodires and pleurodires) from 3 continents (North America, Africa, Asia). In addition, I published a taxonomic description from TBFs collected previously by the Bullard Lab in South America (Peru). I used alpha taxonomy, light microscopy, nucleotide sequencing techniques (PCR; large subunit ribosomal DNA [28S], small subunit ribosomal DNA [18S], and Cytochrome c oxidase subunit I [CO1]), and molecular phylogenetic analyses (Baysian inferences) to (i) redescribe a species long-regarded as a species complex, (ii) emend a genus that lacked extant type material and described a new species of the genus, (iii) proposed two new genera and described two new species, and (iv) shed light on a particular taxonomically-troubling polystome; including the first record of this lineage of parasite in the alligator snapping turtle or from Mississippi. The turtle blood fluke work is published in The Journal of Parasitology, Folia Parasitologica, and Systematic Parasitology. The final chapter detailing the polystome was in review at the time of the defense of this thesis.