Quantitative and comparative analysis of helminth diversity, distribution, and ecological factors in 12 Spanish anuran species

Abstract

The study of parasitic organisms in wild animals in Spain began in the late 19th century, yet information remains fragmented. For anurans, understanding parasite diversity is critical due to their ecological roles and influence on host populations. This study compiled data on helminth parasites of Spanish anurans from 61 scientific publications. The analysis revealed the highest parasite richness in Ranidae (66 species), followed by Bufonidae (19), Hylidae, and Alytidae (10 each), with Pelobatidae showing the lowest (2). Pelophylax perezi hosted the most parasite species (52), while Alytes cisternasii had the fewest (1). A total of 78 helminth species were identified across five groups: trematodes (41), nematodes (27), monogeneans (5), acanthocephalans (3), and cestodes (2). Cosmocerca ornata and Oswaldocruzia filiformis were the most frequently recorded, each cited five times. Habitat-activity interactions significantly influenced parasite richness (p < 0.01). Sørensen’s similarity index for anuran families ranged from 2.94% to 40.00%, while cluster analysis using Morisita’s index indicated heterogeneous groupings. Host-parasite networks showed greater complexity in terrestrial and arboreal hosts, with significant differences among habitat types and activity patterns (p < 0.001). Helminths in 61.29% of Spanish anuran species remain unidentified, highlighting research gaps. This review underscores the need for interdisciplinary collaboration to address habitat loss, climate change, and taxonomic uncertainties. Ectoparasitic arthropods and protozoa were excluded.