Xth EMOP, August 2008

Genetic relationships among species of Contracaecum Railliet & Henry, 1912 and Phocascaris Höst, 1932 (Nematoda: Anisakidae) from pinnipeds inferred from mitochondrial cox2 sequences, and congruence with allozyme data

¹ Department of Public Health Sciences (DSSP), Section of Parasitology, “Sapienza” - University of Rome, Italy
² Department of Ecology and Sustainable Economic Development (DECOS), Tuscia University, Viterbo, Italy
³ Cawthron Institute, Nelson, New Zealand
⁴ Laboratorio de Parasitologia, Departamento de Biologia, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes, Argentina
⁵ Institutt for Biologi, Universitetet i Bergen, Norway

^* Correspondence: Simonetta Mattiucci, Department of Public Health Sciences, Section of Parasitology, “Sapienza” – University of Rome, Ple Aldo Moro, 5, 00185 Rome, Italy. Tel. & fax: ++39 06 49914894. E-mail: simonetta.mattiucci@uniroma1.it

Abstract

The genetic relationships among 11 taxa, belonging to the genus Contracaecum (C. osculatum A, C. osculatum B, C. osculatum (s.s.), C. osculatum D, C. osculatum E, C. osculatum baicalensis, C. mirounga, C. radiatum, C. ogmorhini (s.s.), C. margolisi) and Phocascaris (Phocascaris cystophorae), parasites as adults of seals, were inferred from sequence analysis (519 bp) of the mitochondrial cytochrome c oxidase subunit II (mtDNA cox2) gene. Phylogenetic analyses obtained from Parsimony (MP) and Neighbour-Joining (NJ) K2P distance values generated similar topologies, each well supported at major nodes. All analyses delineated two main clades: the first encompassing the parasites of the phocid seals, i.e. the C. osculatum species complex, C. osculatum baicalensis, C. mirounga and C. radiatum, with the latter two species forming a separate subclade; the second including the parasites of otarids, i.e. C. ogmorhini (s.s.) and C. margolisi. An overall high congruence between mtDNA inferred tree topologies and those produced from nuclear data sets (20 allozyme loci) was observed. Comparison of the phylogenetic hypothesis here produced for Contracaecum spp. plus Phocascaris with those currently available for their definitive hosts (pinnipeds) suggests parallelism between hosts and parasite phylogenetic tree topologies.