Parasite diversity in sea turtles of the temperate SW Atlantic: a bridge between systematics and ecology

Abstract

Parasite studies can provide insights into important aspects of host ecology, which can be particularly important for species of conservation concern. This research focused on the parasite diversity of two sea turtle species —the loggerhead Caretta caretta and the leatherback Dermochelys coriacea— in the temperate South West Atlantic, a region and species relatively understudied. Over a 15-year period (2008–2023), 30 sea turtles were sampled from the northern coast of Argentina. Through morphological and molecular tools, we identified five parasite species (the digeneans Pyelosomum renicapite and Pleurogonius longiusculus, the nematodes Kathlania leptura and Sulcascaris sulcata and the leech Ozobranchus margoi) in loggerheads and two digeneans (P. renicapite and Orchidasma amphiorchis) in leatherbacks. All the species constitute the first report of the parasite in Argentina, and O. amphiorchis represents a new host-parasite association for leatherbacks. Comparative biogeographic analysis using the Regional Management Unit (RMU) framework suggested that parasites could reveal connectivity between RMUs, although there are several information gaps. An increasing number of parasite studies can help understand sea turtle feeding ecology, ontogenetic shifts and health status and thus enhance conservation strategies for sea turtles globally.