New publication in *Parasitology*

Life cycles are extremely important for understanding the parasites around us. But even in the case of large, easily visible species, the life cycles of their parasites are often poorly understood, which also leaves their impact on the food web unclear. Marliese Truter from the North West University in South Africa and Annabell Hüsken from the University of Duisburg-Essen have now shed light on this and succeeded in mapping the life cycle of a parasite of a charismatic apex predator.

Neofibricola smiti is a fluke that was only described in 2022 from the gut of the Nile crocodile (Crocodylus niloticus) in South Africa. The adult specimens from the crocodile matched genetically with metacercariae from the large clawed frog (Xenopus muelleri). Truter, Hüsken and their colleagues have now been able to identify further hosts of the trematode through phylogenetic analyses of sporocysts, cercariae and metacercariae from snails and fish. With the identification of freshwater snails of the genus Bulinus as the first intermediate host, it has thus been possible for the first time to fully reconstruct the life cycle of a trematode from African crocodiles.

The metacercaria recovered from the eyes of the African catfish (Clarias gariepinus) also reveals a significantly wider range of potential second intermediate hosts, or points to more complex transmission patterns such as the use of paratenic hosts. The paper impressively demonstrates how a combination of molecular and morphological methods can reveal the life cycles of enigmatic parasites, and how little is actually known about the parasites themselves, even in species that are relatively easy to observe.