Molecular and New Morphological Data on Nematode Hedruris dratini Found Parasitizing Pseudis minuta (Anura: Hylidae)

Abstract

Hedruris has a worldwide distribution, parasitizing lampreys, fishes, frogs, and lizards. In SouthAmerica, 4 species have been reported on frogs (Hedruris heyeri, Hedruris juninensis, Hedruris mon-iezi, and Hedruris mucronifer), 3 on fishes (Hedruris basilichtensis, Hedruris orestiae, and Hedrurissuttonae), and 1 on turtles (Hedruris dratini). We examined a frog (Pseudis minuta) found dead inthe Pescado stream, Argentina, searching for parasites. A Hedruris sp. was found and subsequentlysubjected to integrative analyses. The 18S rDNA was sequenced, and specimens were examinedusing electron and optical microscopy. Genetic analysis grouped this nematode with H. dratini. Itsmorphology was similar to that species but differed in having bifid derid in frogs, compared to asimple deirid in turtles. This difference could result from various causes, such as host-parasite inter-action or a teratological feature, or it could indicate high morphological variability. To resolvethis, molecular analysis of all described Hedruris species is necessary, in addition to morphologicalstudies. According to the prevalence and intensity of infection reported in the literature, the defini-tive host of H. dratini is likely the turtle. However, the nematode may use different hosts, or thefrog may have ingested an amphipod harboring the parasite’s intermediate stage. This is the firstHedruris parasite of frogs to be sequenced and represents, after H. mucronifer, the second report ofthe genus in anurans from Argentina.