Sistematica molecolare e coevoluzione parassita-ospite in specie del genere Contracaecum (Nematoda : Anisakidae), parassite di uccelli ittiofagi
Author(s)
Paoletti, Michela
Date Issued
June 24, 2009
Type
Doctoral Thesis
Abstract
Nematodes of genus Contracaecum are parasites of fish-eating birds and fishes, at adult and larval
stage respectively. The aim of this study has been to analyze the genetic variation of Contracaecum adult and larval populations, sampled in several species of fish-eating birds (Pelecanidae, Phalacrocoracidae, Ardeidae, Alcidae and Spheniscidae) and fishes, coming from the whole world.
The analyses were performed using two molecular markers, a nuclear one (20 enzyme loci) and a
mitochondrial cox-2 gene (sequences, 519 bp). The genetic survey has allowed identifying 12
species belonging to the genus Contracaecum, including 3 sibling species belonging to C.
multipapillatum (s.l.) complex and 2 new taxa, here named C. bioccai and Contracaecum sp.. Also,
it has been recognized the validity as biological species of C. rudolphii A and B, C. septentrionale,
C. microcephalum, C. micropapillatum, C. pelagicum and C. variegatum. Moreover, the larval
identification has concurred to clarify partially the life-cycle of some Contracaecum species, and
the relationships with the definitive host biology and ecology. Finally, molecular markers analyses evidenced some parallelisms between phylogenies of Contracaecum species and those of their definitive hosts (fish-eating birds), emphasizing possible parasite-host co-speciation.
Additional information
Dottorato di ricerca in Ecologia e gestione delle risorse biologiche
Subjects
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