Diet and helminth parasites of freshwater turtles Mesoclemmys tuberculata, Phrynops geoffroanus (Pleurodira: Chelidae) and Kinosternon scorpioides (Criptodyra: Kinosternidae) in a semiarid region, Northeast of Brazil

In this study, the Kinosternon scorpioides, Mesoclemmys tuberculata and Phrynops geoffroanus freshwater turtles collected in the Cariús River, State of Ceará, were analysed as to their diet composition and presence of helminths. Among the 63 examined turtles 55 (87.3%) were parasitized. We found three Nematoda species (Physaloptera retusa, Serpinema monospiculatus and Spiroxys figueiredoi) and one Trematoda species (Gorgoderina sp.). Phrynops geoffroanus had the highest indexes of prevalence (97.56%) and mean intensity of infection (33.5), followed by M. tuberculata (70% and 12.64, respectively) and K. scorpioides (50% and three, respectively). Host body size was positively related to helminths abundance in both male and female Chelidae species. A significant difference in helminths abundance between the sexes was found only in P. geoffroanus, where females had more parasites than males. Regarding diet, the main food items ingested by M. tuberculata were Odonata nymphs (Aeshnidae and Libellulidae), whilst P. geoffroanus feeds mainly on Diptera larvae (Chironomidae), Odonata nymph (Aeshnidae) and Notonectidae, and only seeds were found in the stomach contents of K. scorpioides. Here, we present the first record of S. monospiculatus parasitizing K. scorpioides, Gorgoderina sp. and P. retusa were reported for the first time in P. geoffroanus, and M. tuberculata represents a new host to P. retusa and S. figueiredoi