Revision der vogelparasitischen Nematoden Mitteleuropas I. Die Gattung Porrocaecum Railliet & Henry, 1912 (Ascaridoidea)

The ascaridoid nematodes of rodents with a redescription ofPorrocaecum ratti

“…The above description leaves no doubt that this species belongs within the genus Porrocaecum sensu Hartwich, 1957. There are 35 or more species in the genus Porrocaecum but, except for the revision by Hartwich (1959) of the mid-European species, this genus has not been the subject of a critical review. Moreover, the morphological features which were considered by Hartwich to be significant in terms of subdivision of the genus are not mentioned in the descrip- Fig.…”

“…Nevertheless, it can be said that, apart from P. herpestum,* which should probably be excluded from the genus because it has no interlabia, P. ratti and P. pennanti appear to be the only species recorded from mammals, all other species being from birds. With regard to the grouping proposed by Hartwich (1959) the two rodent species fall most nearly into the group which occurs in birds of prey, as they have no posterior processes on the anterior prolongations of the labial pulp. In the grouping proposed by Osche (1959), based on studies of the lifehistory of Porrocaecum species, the species which occur in raptorial birds and which are acquired by the definitive host through the ingestion of insectivores and rodents are regarded as more highly evolved than those occurring in invertebrateor fish-eating birds.…”

“…The specimens have features characteristic of the genus Porrocaecum, including bilateral excretory system, excretory pore behind the nerve ring, ventriculus without appendix, intestinal caecum, alate spicules, and postcloacal papillae of male distributed somewhat irregularly on the ventral surface of the tail. On the other hand, they do not have interlabia and consequently should not be included in the genus Porrocaecum, as defined by Hartwich (1959). Sprent (1957) in Rattus fuscipes ( = assimilis) in Queensland, Australia, and placed in the genus Toxocara by Warren (1971).…”