Parasitology



Phylogenetic relationships of the family Campulidae (Trematoda) based on 18S rRNA sequences


M. FERNANDEZ a1a3c1p1, D. T. J. LITTLEWOOD a1, A. LATORRE a2, J. A. RAGA a3 and D. ROLLINSON a1
a1 Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK
a2 Departamento de Genética, Universitat de València, Dr Moliner, 50, 46100 Burjasot, Valencia, Spain
a3 Departamento de Biología Animal, Universitat de València, Dr Moliner, 50, 46100 Burjasot, Valencia, Spain

Abstract

Traditionally, the family Campulidae has been associated either with the family Fasciolidae, parasites of ruminants, or the Acanthocolpidae, parasites of fishes, based on morphological similarities. Since morphology does not seem to resolve clearly the problem of the relationships of campulids, we have used the sequences of the 18S rRNA gene of the campulids Zalophotrema hepaticum, Campula oblonga and Nasitrema globicephalae, the fasciolid Fasciola hepatica, the acanthocolpid Stephanostomum baccatum and the outgroup Schistosoma mansoni to infer a phylogeny. Maximum parsimony and neighbour-joining methods were applied. Both methods indicated that campulids are closer to acanthocolpids than fasciolids. In order to confirm this relationship, we generated a second phylogeny using all the partial sequences of the 18S published for trematodes: Lobatostoma manteri, Echinostoma caproni, Calicophoron calicophorum, Tetracerasta blepta, Gyliauchen sp. and Opistorchis viverrini, plus those mentioned above, and Dicrocoelium dendriticum. The aspidogastrean L. manteri was used as the outgroup. Results were identical to the first analysis. According to this and the most recent Digenean phylogeny, which considers campulids and acanthocolpids as sister groups, we suggest that a common origin for these 2 groups would imply a host-switching process. The life-cycle of acanthocolpids includes marine gastropods as first intermediate hosts, and fishes as second intermediate and definitive hosts. In this context, the hypothesis would be that trematodes whose cycle ended in fishes were able to switch to mammalian hosts.

(Received February 5 1998)
(Revised April 20 1998)
(Accepted April 24 1998)


Key Words: Campulidae; Fasciolidae; Acanthocolpidae; 18S rRNA; host switching.

Correspondence:
c1 Corresponding author.
p1 Current address: Departamento de Biología Animal, Universitat de València, Dr Moliner, 50, E-46100-Burjasot, Valencia, Spain. Tel: +34 96 398-3221. Fax: +34 96 3864372. E-mail: Mercedes.Fernandez@uv.es


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