Parasite assemblages of Zenopsis conchifer are characterised for the first known time in an ecotonal region.
Parasite communities are composed of species of different zoogeographical origin.
Repeatable distribution patterns of parasites were observed when different host species were analysed.
These patterns showed a tight correspondence with the existing zoogeographical classification in the region.
The utility of parasites as indicators of ecotonal regions in the marine environment is demonstrated.