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 focuses on the parasite diversity of two sea turtle species —the loggerhead Caretta caretta and leatherback Dermochelys coriacea sea turtles— in the temperate Southwest 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 P. longiusculus, the nematodes Kathlania leptura and Sulcascaris sulcata and the leech Ozobranchus margoi) in loggerheads; and two digeneans (P. renicapite and O. amphiorchis) in leatherbacks. All 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 framework revealed that parasites could reveal connectivity between RMUs, though there are several information gaps. Increasing parasite studies can help understand sea turtle feeding ecology, ontogenetic shift and health status, and thus enhance conservation strategies for sea turtles globally.