Mattiucci, S. and Cianchi, R. and Nascetti, G. and Paggi, L. and Sardella, N. and Timi, J. and Webb, S.C. and Bastida, R. and Rodriguez, D. and Bullini, L.
Genetic evidence of two sibling species within the Contracoecum ogmorhini Johnson & Mawson 1941 complex (Nematoda; Anisakidae) from otariid seals in boreal and austral regions.
Systematic Parasitology, 54(1),
Genetic variation of Contracaecum ogmorhini (sensu lato) populations from different otariid seals of the northern
and southern hemisphere was studied on the basis of 18 enzyme loci as well as preliminary sequence analysis of
the mitochondrial cyt b gene (260 bp). Samples were collected from Zalophus californianus in the boreal region
and from Arctocephalus pusillus pusillus, A. pusillus doriferus and A. australis from the austral region. Marked
genetic heterogeneity was found between C. ogmorhini (sensu lato) samples from the boreal and austral region,
respectively. Two loci (Mdh-2 and NADHdh) showed fixed differences and a further three loci (Iddh, Mdh-1 and
6Pgdh) were highly differentiated between boreal and austral samples. Their average genetic distance was DNei =
0.36 at isozyme level. At mitochondrial DNA level, an average proportion of nucleotide substitution of 3.7% was
observed. These findings support the existence of two distinct sibling species, for which the names C. ogmorhini
(sensu stricto) and C. margolisi n. sp., respectively, for the austral and boreal taxon, are proposed. A description
for C. margolisi n. sp. is provided. No diagnostic morphological characters have so far been detected; on the other hand, two enzyme loci, Mdh-2 and NADHdh, fully diagnostic between the two species, can be used for the routine identification of males, females and larval stages. Mirounga leonina was found to host C. ogmorhini (s.s.) inmixed infections with C. osculatum (s.l.) (of which C. ogmorhini (s.l.) was in the past considered to be a synonym)
and C. miroungae; no hybrid genotypes were found,confirming the reproductive isolation of these three anisakid species. The hosts and geographical range so far recorded for C. margolisi n. sp. and C. ogmorhini (s.s.) are given.
||Genetic evidence of two sibling species within the Contracoecum ogmorhini Johnson & Mawson 1941 complex (Nematoda; Anisakidae) from otariid seals in boreal and austral regions
|Journal or Publication Title:
||Universidad Nacional de Mar del Plata
||02 Oct 2012 16:33
||02 Oct 2012 16:33
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