Endoparasites of Crotalus tzabcan (Serpentes: Viperidae), with a checklist in rattlesnakes.

The helminth and pentastomid fauna of 50 specimens of Crotalus tzabcan from the Yucatán Peninsula, Mexico is documented. The examination revealed the presence of three nematode species (Hastospiculum onchocercum, Hexametra boddaertii, and Travassosascaris araujoi), and one pentastomid (Porocephalus crotali). The threee nematode species had the same prevalence (2%), while the pentastomid had a higher prevalence (8%). The pentastomid P. crotali was the most abundant and intense parasite, although it was only found in four snake hosts. Crotalus tzabcan acts as definitive host for the adult helminths and pentastomids, with rodents as the probable intermediate hosts. This work represents the first systematic survey on the parasitic helminth and pentastomid fauna of C. tzabcan, and includes four new geographical records. Additionally, a checklist of helminths and pentastomids reported for Crotalus and Sistrurus is provided. To date, a total of 32 helminth and 7 pentastomid species have been recorded as parasites of rattlesnakes. Nematoda possessed the highest species richness. The genera with the highest number of host species were Mesocestoides and Hexametra, followed by Kalicephalus. The rattlesnake species with the highest number of reported parasites was C. durissus (18 nematodes and 2 pentastomids).