On the life cycle and morphology of development stages of Paraspiralatus sakeri Gibbons et al., 2004 (Nematoda: Spiroidea, Spirocercidae), a heteroxenic stomach parasite of falcons.

Pitted darkling beetles (Adesmia cancellata) were infected with nematode eggs found in the alimentary tract of a gyrfalcon (Falco rusticolus) naturally infected with Paraspiralatus sakeri. Third-stage larvae in numbers between 1 and 84 were removed from the beetles 5 weeks postinfection and were used for morphological studies as well as to infect domestic chicken, yellow-bellied geckos (Hemidactylus flaviviridis) and fringe-toed lizards (Acanthodactylus schmidti). All experimental animals, necropsied 4-38 weeks later, were positive for spirally coiled nematode larvae located under the skin and in the interstitium of skeletal muscles. Despite similarities in general morphology, larvae from beetles and reptiles and chicken differed strikingly in the total body length and body width. Differences in length of the muscular oesophagus and distances of cervical papillae, nerve ring and excretory pore from the anterior end were less distinct. Morphology of these larvae matched with larvae found in subcutaneous cysts in naturally infected houbara bustards (Chlamydotis macqueeni) from Pakistan and UAE as well as with those detected in the muscles of an ocellated skink (Chalcides ocellatus).