Molecular evidence for new sibling species of Contracaecum rudolphii complex (Nematoda: Anisakidae) parasites of cormorants from the Austral hemisphere, and genetic relationships with congeners

S. MATTIUCCI; M. PAOLETTI; L. GARBIN; F. FONTANEAU; C. TACCARI; L. RUGGIERO; G. NASCETTI; D. GONZÁLEZ ACUÑA

La Plata

Congreso; V Congreso Argentino de Parasitología; 2009

Fac. Cs. Nat y Museo, UNLP

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:IT; mso-fareast-language:IT;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Adult nematodes of the genus Contracaecum Railliet & Henry, 1912 have been reported as parasites of fish-eating birds and seals throughout the world. Considered as valid, C. rudolphii (Hartwich, 1964) is reported as a parasite of several fish-eating birds from the southern and northern hemisphere. Object is to report the detection of new sibling species belonging to the C. rudolphii complex from cormorants of the Southern hemisphere. Genetic variation inferred from nuclear markers (18 allozyme loci) and mitochondrial gene sequence analysis (519 bp mtDNA cox) was analyzed in C. rudolphii (s.l.) specimens collected from Ph. brasilianus from the Santa Elena Lagoon, Chile, and Ph. verrucosus from Kerguelen Islands (subantarctic region). Genetic divergence and relationships inferred at the nuclear and mitochondrial level between the samples of C. rudolphii collected from Phalacrocoracidae of the Austral region with respect to the other Contracaecum spp. from waterbirds, previously characterized genetically (i.e. C. septentrionale, C. bioccai, C. microcephalum, C. micropapillatum, C. pelagicum, C. variegatum, and the complex C. multipapillatum A, B andC) have been estimated. Distinct fixed allele differences were found at some allozyme loci in both samples of C. rudolphii from Ph. brasilianus and Ph. verrucosus. MP and NJ trees inferred from mtDNA cox2 have shown concordant and supported topologies in depicting all the specimens from Ph. brasilianus and those from Ph. verrucosus as forming two separated lineages, well distinct from those formed by other congeners. Results support the existence of two new sibling species of the C. rudolphii complex.