Acanthocephala Species of Mammals in Türkiye and A New Species Record from Foxes.

Acanthocephaliasis is a zoonotic parasitic infection of vertebrates. The phylum Acanthocephala contains nearly 1500 acanthocephalan species. The Archiacanthocephala class is observed in terrestrial habitats and usually has a large, spineless trunk. Acanthocephalans are parasitic worms that use insects as intermediate hosts in their two-host life cycles. Insects, millipedes, and crustaceans in terrestrial areas serve as intermediate hosts and birds and mammals as definitive hosts. Acanthocephalans collected from the red fox ( Vulpes vulpes ) found dead on the road to Sarıkamış-Kars in 1995 and stored in formaldehyde were kept in Ondokuz Mays University Faculty of Veterinary Medicine, Veterinary Parasitology Laboratory Museum until 2023 after our parasitological study found an infected red fox with Pachysentis sp. This study provides the anatomy of the acanthocephalans and the laboratory practice necessary for a good and reliable diagnosis. This study reports a new species, Pachysentis sp., of acanthocephalan (thorny-headed worm) found in red foxes for Türkiye. On the basis of relevant articles, we have created a key to Acanthocephala species occurring in mammals. Keywords: Acanthocephala, Pachysentis, Türkiye, Vulpes vulpes.